Merge commit '91820d46b5f3065c2fded3cdf65d305715b33bb1' into HEAD

6 files changed, 1286 insertions, 395 deletions

diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index 033d981..6d48ab7 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -37,6 +37,8 @@
 #include <media/stagefright/MetaData.h>
 #include <media/stagefright/Utils.h>
 
+#include <utils/Mutex.h>
+
 #include <ctype.h>
 #include <inttypes.h>
 #include <openssl/aes.h>
@@ -58,32 +60,57 @@ LiveSession::LiveSession(
                     : 0)),
       mPrevBandwidthIndex(-1),
       mStreamMask(0),
+      mNewStreamMask(0),
+      mSwapMask(0),
       mCheckBandwidthGeneration(0),
+      mSwitchGeneration(0),
       mLastDequeuedTimeUs(0ll),
       mRealTimeBaseUs(0ll),
       mReconfigurationInProgress(false),
-      mDisconnectReplyID(0) {
+      mSwitchInProgress(false),
+      mDisconnectReplyID(0),
+      mSeekReplyID(0) {
     if (mUIDValid) {
         mHTTPDataSource->setUID(mUID);
     }
 
-    mPacketSources.add(
-            STREAMTYPE_AUDIO, new AnotherPacketSource(NULL /* meta */));
-
-    mPacketSources.add(
-            STREAMTYPE_VIDEO, new AnotherPacketSource(NULL /* meta */));
+    mStreams[kAudioIndex] = StreamItem("audio");
+    mStreams[kVideoIndex] = StreamItem("video");
+    mStreams[kSubtitleIndex] = StreamItem("subtitles");
 
-    mPacketSources.add(
-            STREAMTYPE_SUBTITLES, new AnotherPacketSource(NULL /* meta */));
+    for (size_t i = 0; i < kMaxStreams; ++i) {
+        mPacketSources.add(indexToType(i), new AnotherPacketSource(NULL /* meta */));
+        mPacketSources2.add(indexToType(i), new AnotherPacketSource(NULL /* meta */));
+    }
 }
 
 LiveSession::~LiveSession() {
 }
 
+sp<ABuffer> LiveSession::createFormatChangeBuffer(bool swap) {
+    ABuffer *discontinuity = new ABuffer(0);
+    discontinuity->meta()->setInt32("discontinuity", ATSParser::DISCONTINUITY_FORMATCHANGE);
+    discontinuity->meta()->setInt32("swapPacketSource", swap);
+    discontinuity->meta()->setInt32("switchGeneration", mSwitchGeneration);
+    discontinuity->meta()->setInt64("timeUs", -1);
+    return discontinuity;
+}
+
+void LiveSession::swapPacketSource(StreamType stream) {
+    sp<AnotherPacketSource> &aps = mPacketSources.editValueFor(stream);
+    sp<AnotherPacketSource> &aps2 = mPacketSources2.editValueFor(stream);
+    sp<AnotherPacketSource> tmp = aps;
+    aps = aps2;
+    aps2 = tmp;
+    aps2->clear();
+}
+
 status_t LiveSession::dequeueAccessUnit(
         StreamType stream, sp<ABuffer> *accessUnit) {
     if (!(mStreamMask & stream)) {
-        return UNKNOWN_ERROR;
+        // return -EWOULDBLOCK to avoid halting the decoder
+        // when switching between audio/video and audio only.
+        return -EWOULDBLOCK;
     }
 
     sp<AnotherPacketSource> packetSource = mPacketSources.valueFor(stream);
@@ -123,6 +150,25 @@ status_t LiveSession::dequeueAccessUnit(
               streamStr,
               type,
               extra == NULL ? "NULL" : extra->debugString().c_str());
+
+        int32_t swap;
+        if (type == ATSParser::DISCONTINUITY_FORMATCHANGE
+                && (*accessUnit)->meta()->findInt32("swapPacketSource", &swap)
+                && swap) {
+
+            int32_t switchGeneration;
+            CHECK((*accessUnit)->meta()->findInt32("switchGeneration", &switchGeneration));
+            {
+                Mutex::Autolock lock(mSwapMutex);
+                if (switchGeneration == mSwitchGeneration) {
+                    swapPacketSource(stream);
+                    sp<AMessage> msg = new AMessage(kWhatSwapped, id());
+                    msg->setInt32("stream", stream);
+                    msg->setInt32("switchGeneration", switchGeneration);
+                    msg->post();
+                }
+            }
+        }
     } else if (err == OK) {
         if (stream == STREAMTYPE_AUDIO || stream == STREAMTYPE_VIDEO) {
             int64_t timeUs;
@@ -144,6 +190,7 @@ status_t LiveSession::dequeueAccessUnit(
 }
 
 status_t LiveSession::getStreamFormat(StreamType stream, sp<AMessage> *format) {
+    // No swapPacketSource race condition; called from the same thread as dequeueAccessUnit.
     if (!(mStreamMask & stream)) {
         return UNKNOWN_ERROR;
     }
@@ -189,6 +236,10 @@ status_t LiveSession::seekTo(int64_t timeUs) {
     sp<AMessage> response;
     status_t err = msg->postAndAwaitResponse(&response);
 
+    uint32_t replyID;
+    CHECK(response == mSeekReply && 0 != mSeekReplyID);
+    mSeekReply.clear();
+    mSeekReplyID = 0;
     return err;
 }
 
@@ -214,15 +265,12 @@ void LiveSession::onMessageReceived(const sp<AMessage> &msg) {
 
         case kWhatSeek:
         {
-            uint32_t replyID;
-            CHECK(msg->senderAwaitsResponse(&replyID));
+            CHECK(msg->senderAwaitsResponse(&mSeekReplyID));
 
             status_t err = onSeek(msg);
 
-            sp<AMessage> response = new AMessage;
-            response->setInt32("err", err);
-
-            response->postReply(replyID);
+            mSeekReply = new AMessage;
+            mSeekReply->setInt32("err", err);
             break;
         }
 
@@ -240,13 +288,23 @@ void LiveSession::onMessageReceived(const sp<AMessage> &msg) {
                     if (what == PlaylistFetcher::kWhatStopped) {
                         AString uri;
                         CHECK(msg->findString("uri", &uri));
-                        mFetcherInfos.removeItem(uri);
+                        if (mFetcherInfos.removeItem(uri) < 0) {
+                            // ignore duplicated kWhatStopped messages.
+                            break;
+                        }
+
+                        tryToFinishBandwidthSwitch();
                     }
 
                     if (mContinuation != NULL) {
                         CHECK_GT(mContinuationCounter, 0);
                         if (--mContinuationCounter == 0) {
                             mContinuation->post();
+
+                            if (mSeekReplyID != 0) {
+                                CHECK(mSeekReply != NULL);
+                                mSeekReply->postReply(mSeekReplyID);
+                            }
                         }
                     }
                     break;
@@ -276,6 +334,8 @@ void LiveSession::onMessageReceived(const sp<AMessage> &msg) {
                         postPrepared(err);
                     }
 
+                    cancelBandwidthSwitch();
+
                     mPacketSources.valueFor(STREAMTYPE_AUDIO)->signalEOS(err);
 
                     mPacketSources.valueFor(STREAMTYPE_VIDEO)->signalEOS(err);
@@ -314,6 +374,27 @@ void LiveSession::onMessageReceived(const sp<AMessage> &msg) {
                     break;
                 }
 
+                case PlaylistFetcher::kWhatStartedAt:
+                {
+                    int32_t switchGeneration;
+                    CHECK(msg->findInt32("switchGeneration", &switchGeneration));
+
+                    if (switchGeneration != mSwitchGeneration) {
+                        break;
+                    }
+
+                    // Resume fetcher for the original variant; the resumed fetcher should
+                    // continue until the timestamps found in msg, which is stored by the
+                    // new fetcher to indicate where the new variant has started buffering.
+                    for (size_t i = 0; i < mFetcherInfos.size(); i++) {
+                        const FetcherInfo info = mFetcherInfos.valueAt(i);
+                        if (info.mToBeRemoved) {
+                            info.mFetcher->resumeUntilAsync(msg);
+                        }
+                    }
+                    break;
+                }
+
                 default:
                     TRESPASS();
             }
@@ -358,6 +439,11 @@ void LiveSession::onMessageReceived(const sp<AMessage> &msg) {
             break;
         }
 
+        case kWhatSwapped:
+        {
+            onSwapped(msg);
+            break;
+        }
         default:
             TRESPASS();
             break;
@@ -375,6 +461,12 @@ int LiveSession::SortByBandwidth(const BandwidthItem *a, const BandwidthItem *b)
     return 1;
 }
 
+// static
+LiveSession::StreamType LiveSession::indexToType(int idx) {
+    CHECK(idx >= 0 && idx < kMaxStreams);
+    return (StreamType)(1 << idx);
+}
+
 void LiveSession::onConnect(const sp<AMessage> &msg) {
     AString url;
     CHECK(msg->findString("url", &url));
@@ -462,6 +554,10 @@ void LiveSession::finishDisconnect() {
     // during disconnection either.
     cancelCheckBandwidthEvent();
 
+    // Protect mPacketSources from a swapPacketSource race condition through disconnect.
+    // (finishDisconnect, onFinishDisconnect2)
+    cancelBandwidthSwitch();
+
     for (size_t i = 0; i < mFetcherInfos.size(); ++i) {
         mFetcherInfos.valueAt(i).mFetcher->stopAsync();
     }
@@ -501,11 +597,13 @@ sp<PlaylistFetcher> LiveSession::addFetcher(const char *uri) {
 
     sp<AMessage> notify = new AMessage(kWhatFetcherNotify, id());
     notify->setString("uri", uri);
+    notify->setInt32("switchGeneration", mSwitchGeneration);
 
     FetcherInfo info;
     info.mFetcher = new PlaylistFetcher(notify, this, uri);
     info.mDurationUs = -1ll;
     info.mIsPrepared = false;
+    info.mToBeRemoved = false;
     looper()->registerHandler(info.mFetcher);
 
     mFetcherInfos.add(uri, info);
@@ -513,54 +611,82 @@ sp<PlaylistFetcher> LiveSession::addFetcher(const char *uri) {
     return info.mFetcher;
 }
 
-status_t LiveSession::fetchFile(
+/*
+ * Illustration of parameters:
+ *
+ * 0      `range_offset`
+ * +------------+-------------------------------------------------------+--+--+
+ * |            |                                 | next block to fetch |  |  |
+ * |            | `source` handle => `out` buffer |                     |  |  |
+ * | `url` file |<--------- buffer size --------->|<--- `block_size` -->|  |  |
+ * |            |<----------- `range_length` / buffer capacity ----------->|  |
+ * |<------------------------------ file_size ------------------------------->|
+ *
+ * Special parameter values:
+ * - range_length == -1 means entire file
+ * - block_size == 0 means entire range
+ *
+ */
+ssize_t LiveSession::fetchFile(
         const char *url, sp<ABuffer> *out,
         int64_t range_offset, int64_t range_length,
+        uint32_t block_size, /* download block size */
+        sp<DataSource> *source, /* to return and reuse source */
         String8 *actualUrl) {
-    *out = NULL;
+    off64_t size;
+    sp<DataSource> temp_source;
+    if (source == NULL) {
+        source = &temp_source;
+    }
 
-    sp<DataSource> source;
+    if (*source == NULL) {
+        if (!strncasecmp(url, "file://", 7)) {
+            *source = new FileSource(url + 7);
+        } else if (strncasecmp(url, "http://", 7)
+                && strncasecmp(url, "https://", 8)) {
+            return ERROR_UNSUPPORTED;
+        } else {
+            KeyedVector<String8, String8> headers = mExtraHeaders;
+            if (range_offset > 0 || range_length >= 0) {
+                headers.add(
+                        String8("Range"),
+                        String8(
+                            StringPrintf(
+                                "bytes=%lld-%s",
+                                range_offset,
+                                range_length < 0
+                                    ? "" : StringPrintf("%lld",
+                                            range_offset + range_length - 1).c_str()).c_str()));
+            }
+            status_t err = mHTTPDataSource->connect(url, &headers);
 
-    if (!strncasecmp(url, "file://", 7)) {
-        source = new FileSource(url + 7);
-    } else if (strncasecmp(url, "http://", 7)
-            && strncasecmp(url, "https://", 8)) {
-        return ERROR_UNSUPPORTED;
-    } else {
-        KeyedVector<String8, String8> headers = mExtraHeaders;
-        if (range_offset > 0 || range_length >= 0) {
-            headers.add(
-                    String8("Range"),
-                    String8(
-                        StringPrintf(
-                            "bytes=%lld-%s",
-                            range_offset,
-                            range_length < 0
-                                ? "" : StringPrintf("%lld", range_offset + range_length - 1).c_str()).c_str()));
-        }
-        status_t err = mHTTPDataSource->connect(url, &headers);
+            if (err != OK) {
+                return err;
+            }
 
-        if (err != OK) {
-            return err;
+            *source = mHTTPDataSource;
         }
-
-        source = mHTTPDataSource;
     }
 
-    off64_t size;
-    status_t err = source->getSize(&size);
-
-    if (err != OK) {
+    status_t getSizeErr = (*source)->getSize(&size);
+    if (getSizeErr != OK) {
         size = 65536;
     }
 
-    sp<ABuffer> buffer = new ABuffer(size);
-    buffer->setRange(0, 0);
+    sp<ABuffer> buffer = *out != NULL ? *out : new ABuffer(size);
+    if (*out == NULL) {
+        buffer->setRange(0, 0);
+    }
 
+    ssize_t bytesRead = 0;
+    // adjust range_length if only reading partial block
+    if (block_size > 0 && (range_length == -1 || buffer->size() + block_size < range_length)) {
+        range_length = buffer->size() + block_size;
+    }
     for (;;) {
+        // Only resize when we don't know the size.
         size_t bufferRemaining = buffer->capacity() - buffer->size();
-
-        if (bufferRemaining == 0) {
+        if (bufferRemaining == 0 && getSizeErr != OK) {
             bufferRemaining = 32768;
 
             ALOGV("increasing download buffer to %zu bytes",
@@ -585,7 +711,9 @@ status_t LiveSession::fetchFile(
             }
         }
 
-        ssize_t n = source->readAt(
+        // The DataSource is responsible for informing us of error (n < 0) or eof (n == 0)
+        // to help us break out of the loop.
+        ssize_t n = (*source)->readAt(
                 buffer->size(), buffer->data() + buffer->size(),
                 maxBytesToRead);
 
@@ -598,17 +726,18 @@ status_t LiveSession::fetchFile(
         }
 
         buffer->setRange(0, buffer->size() + (size_t)n);
+        bytesRead += n;
     }
 
     *out = buffer;
     if (actualUrl != NULL) {
-        *actualUrl = source->getUri();
+        *actualUrl = (*source)->getUri();
         if (actualUrl->isEmpty()) {
             *actualUrl = url;
         }
     }
 
-    return OK;
+    return bytesRead;
 }
 
 sp<M3UParser> LiveSession::fetchPlaylist(
@@ -619,9 +748,9 @@ sp<M3UParser> LiveSession::fetchPlaylist(
 
     sp<ABuffer> buffer;
     String8 actualUrl;
-    status_t err = fetchFile(url, &buffer, 0, -1, &actualUrl);
+    ssize_t  err = fetchFile(url, &buffer, 0, -1, 0, NULL, &actualUrl);
 
-    if (err != OK) {
+    if (err <= 0) {
         return NULL;
     }
 
@@ -816,8 +945,25 @@ status_t LiveSession::selectTrack(size_t index, bool select) {
     return err;
 }
 
+bool LiveSession::canSwitchUp() {
+    // Allow upwards bandwidth switch when a stream has buffered at least 10 seconds.
+    status_t err = OK;
+    for (size_t i = 0; i < mPacketSources.size(); ++i) {
+        sp<AnotherPacketSource> source = mPacketSources.valueAt(i);
+        int64_t dur = source->getBufferedDurationUs(&err);
+        if (err == OK && dur > 10000000) {
+            return true;
+        }
+    }
+    return false;
+}
+
 void LiveSession::changeConfiguration(
         int64_t timeUs, size_t bandwidthIndex, bool pickTrack) {
+    // Protect mPacketSources from a swapPacketSource race condition through reconfiguration.
+    // (changeConfiguration, onChangeConfiguration2, onChangeConfiguration3).
+    cancelBandwidthSwitch();
+
     CHECK(!mReconfigurationInProgress);
     mReconfigurationInProgress = true;
 
@@ -833,21 +979,14 @@ void LiveSession::changeConfiguration(
     CHECK_LT(bandwidthIndex, mBandwidthItems.size());
     const BandwidthItem &item = mBandwidthItems.itemAt(bandwidthIndex);
 
-    uint32_t streamMask = 0;
-
-    AString audioURI;
-    if (mPlaylist->getAudioURI(item.mPlaylistIndex, &audioURI)) {
-        streamMask |= STREAMTYPE_AUDIO;
-    }
-
-    AString videoURI;
-    if (mPlaylist->getVideoURI(item.mPlaylistIndex, &videoURI)) {
-        streamMask |= STREAMTYPE_VIDEO;
-    }
+    uint32_t streamMask = 0; // streams that should be fetched by the new fetcher
+    uint32_t resumeMask = 0; // streams that should be fetched by the original fetcher
 
-    AString subtitleURI;
-    if (mPlaylist->getSubtitleURI(item.mPlaylistIndex, &subtitleURI)) {
-        streamMask |= STREAMTYPE_SUBTITLES;
+    AString URIs[kMaxStreams];
+    for (size_t i = 0; i < kMaxStreams; ++i) {
+        if (mPlaylist->getTypeURI(item.mPlaylistIndex, mStreams[i].mType, &URIs[i])) {
+            streamMask |= indexToType(i);
+        }
     }
 
     // Step 1, stop and discard fetchers that are no longer needed.
@@ -859,10 +998,15 @@ void LiveSession::changeConfiguration(
 
         // If we're seeking all current fetchers are discarded.
         if (timeUs < 0ll) {
-            if (((streamMask & STREAMTYPE_AUDIO) && uri == audioURI)
-                    || ((streamMask & STREAMTYPE_VIDEO) && uri == videoURI)
-                    || ((streamMask & STREAMTYPE_SUBTITLES) && uri == subtitleURI)) {
-                discardFetcher = false;
+            // delay fetcher removal
+            discardFetcher = false;
+
+            for (size_t j = 0; j < kMaxStreams; ++j) {
+                StreamType type = indexToType(j);
+                if ((streamMask & type) && uri == URIs[j]) {
+                    resumeMask |= type;
+                    streamMask &= ~type;
+                }
             }
         }
 
@@ -873,17 +1017,20 @@ void LiveSession::changeConfiguration(
         }
     }
 
-    sp<AMessage> msg = new AMessage(kWhatChangeConfiguration2, id());
+    sp<AMessage> msg;
+    if (timeUs < 0ll) {
+        // skip onChangeConfiguration2 (decoder destruction) if switching.
+        msg = new AMessage(kWhatChangeConfiguration3, id());
+    } else {
+        msg = new AMessage(kWhatChangeConfiguration2, id());
+    }
     msg->setInt32("streamMask", streamMask);
+    msg->setInt32("resumeMask", resumeMask);
     msg->setInt64("timeUs", timeUs);
-    if (streamMask & STREAMTYPE_AUDIO) {
-        msg->setString("audioURI", audioURI.c_str());
-    }
-    if (streamMask & STREAMTYPE_VIDEO) {
-        msg->setString("videoURI", videoURI.c_str());
-    }
-    if (streamMask & STREAMTYPE_SUBTITLES) {
-        msg->setString("subtitleURI", subtitleURI.c_str());
+    for (size_t i = 0; i < kMaxStreams; ++i) {
+        if (streamMask & indexToType(i)) {
+            msg->setString(mStreams[i].uriKey().c_str(), URIs[i].c_str());
+        }
     }
 
     // Every time a fetcher acknowledges the stopAsync or pauseAsync request
@@ -895,6 +1042,11 @@ void LiveSession::changeConfiguration(
 
     if (mContinuationCounter == 0) {
         msg->post();
+
+        if (mSeekReplyID != 0) {
+            CHECK(mSeekReply != NULL);
+            mSeekReply->postReply(mSeekReplyID);
+        }
     }
 }
 
@@ -914,18 +1066,13 @@ void LiveSession::onChangeConfiguration2(const sp<AMessage> &msg) {
     uint32_t streamMask;
     CHECK(msg->findInt32("streamMask", (int32_t *)&streamMask));
 
-    AString audioURI, videoURI, subtitleURI;
-    if (streamMask & STREAMTYPE_AUDIO) {
-        CHECK(msg->findString("audioURI", &audioURI));
-        ALOGV("audioURI = '%s'", audioURI.c_str());
-    }
-    if (streamMask & STREAMTYPE_VIDEO) {
-        CHECK(msg->findString("videoURI", &videoURI));
-        ALOGV("videoURI = '%s'", videoURI.c_str());
-    }
-    if (streamMask & STREAMTYPE_SUBTITLES) {
-        CHECK(msg->findString("subtitleURI", &subtitleURI));
-        ALOGV("subtitleURI = '%s'", subtitleURI.c_str());
+    AString URIs[kMaxStreams];
+    for (size_t i = 0; i < kMaxStreams; ++i) {
+        if (streamMask & indexToType(i)) {
+            const AString &uriKey = mStreams[i].uriKey();
+            CHECK(msg->findString(uriKey.c_str(), &URIs[i]));
+            ALOGV("%s = '%s'", uriKey.c_str(), URIs[i].c_str());
+        }
     }
 
     // Determine which decoders to shutdown on the player side,
@@ -935,15 +1082,12 @@ void LiveSession::onChangeConfiguration2(const sp<AMessage> &msg) {
     // 2) its streamtype was already active and still is but the URI
     //    has changed.
     uint32_t changedMask = 0;
-    if (((mStreamMask & streamMask & STREAMTYPE_AUDIO)
-                && !(audioURI == mAudioURI))
-        || (mStreamMask & ~streamMask & STREAMTYPE_AUDIO)) {
-        changedMask |= STREAMTYPE_AUDIO;
-    }
-    if (((mStreamMask & streamMask & STREAMTYPE_VIDEO)
-                && !(videoURI == mVideoURI))
-        || (mStreamMask & ~streamMask & STREAMTYPE_VIDEO)) {
-        changedMask |= STREAMTYPE_VIDEO;
+    for (size_t i = 0; i < kMaxStreams && i != kSubtitleIndex; ++i) {
+        if (((mStreamMask & streamMask & indexToType(i))
+                && !(URIs[i] == mStreams[i].mUri))
+                || (mStreamMask & ~streamMask & indexToType(i))) {
+            changedMask |= indexToType(i);
+        }
     }
 
     if (changedMask == 0) {
@@ -969,68 +1113,54 @@ void LiveSession::onChangeConfiguration2(const sp<AMessage> &msg) {
 }
 
 void LiveSession::onChangeConfiguration3(const sp<AMessage> &msg) {
+    mContinuation.clear();
     // All remaining fetchers are still suspended, the player has shutdown
     // any decoders that needed it.
 
-    uint32_t streamMask;
+    uint32_t streamMask, resumeMask;
     CHECK(msg->findInt32("streamMask", (int32_t *)&streamMask));
+    CHECK(msg->findInt32("resumeMask", (int32_t *)&resumeMask));
 
-    AString audioURI, videoURI, subtitleURI;
-    if (streamMask & STREAMTYPE_AUDIO) {
-        CHECK(msg->findString("audioURI", &audioURI));
-    }
-    if (streamMask & STREAMTYPE_VIDEO) {
-        CHECK(msg->findString("videoURI", &videoURI));
-    }
-    if (streamMask & STREAMTYPE_SUBTITLES) {
-        CHECK(msg->findString("subtitleURI", &subtitleURI));
+    for (size_t i = 0; i < kMaxStreams; ++i) {
+        if (streamMask & indexToType(i)) {
+            CHECK(msg->findString(mStreams[i].uriKey().c_str(), &mStreams[i].mUri));
+        }
     }
 
     int64_t timeUs;
+    bool switching = false;
     CHECK(msg->findInt64("timeUs", &timeUs));
 
     if (timeUs < 0ll) {
         timeUs = mLastDequeuedTimeUs;
+        switching = true;
     }
     mRealTimeBaseUs = ALooper::GetNowUs() - timeUs;
 
-    mStreamMask = streamMask;
-    mAudioURI = audioURI;
-    mVideoURI = videoURI;
-    mSubtitleURI = subtitleURI;
+    mNewStreamMask = streamMask;
 
-    // Resume all existing fetchers and assign them packet sources.
+    // Of all existing fetchers:
+    // * Resume fetchers that are still needed and assign them original packet sources.
+    // * Mark otherwise unneeded fetchers for removal.
+    ALOGV("resuming fetchers for mask 0x%08x", resumeMask);
     for (size_t i = 0; i < mFetcherInfos.size(); ++i) {
         const AString &uri = mFetcherInfos.keyAt(i);
 
-        uint32_t resumeMask = 0;
-
-        sp<AnotherPacketSource> audioSource;
-        if ((streamMask & STREAMTYPE_AUDIO) && uri == audioURI) {
-            audioSource = mPacketSources.valueFor(STREAMTYPE_AUDIO);
-            resumeMask |= STREAMTYPE_AUDIO;
-        }
-
-        sp<AnotherPacketSource> videoSource;
-        if ((streamMask & STREAMTYPE_VIDEO) && uri == videoURI) {
-            videoSource = mPacketSources.valueFor(STREAMTYPE_VIDEO);
-            resumeMask |= STREAMTYPE_VIDEO;
+        sp<AnotherPacketSource> sources[kMaxStreams];
+        for (size_t j = 0; j < kMaxStreams; ++j) {
+            if ((resumeMask & indexToType(j)) && uri == mStreams[j].mUri) {
+                sources[j] = mPacketSources.valueFor(indexToType(j));
+            }
         }
 
-        sp<AnotherPacketSource> subtitleSource;
-        if ((streamMask & STREAMTYPE_SUBTITLES) && uri == subtitleURI) {
-            subtitleSource = mPacketSources.valueFor(STREAMTYPE_SUBTITLES);
-            resumeMask |= STREAMTYPE_SUBTITLES;
+        FetcherInfo &info = mFetcherInfos.editValueAt(i);
+        if (sources[kAudioIndex] != NULL || sources[kVideoIndex] != NULL
+                || sources[kSubtitleIndex] != NULL) {
+            info.mFetcher->startAsync(
+                    sources[kAudioIndex], sources[kVideoIndex], sources[kSubtitleIndex]);
+        } else {
+            info.mToBeRemoved = true;
         }
-
-        CHECK_NE(resumeMask, 0u);
-
-        ALOGV("resuming fetchers for mask 0x%08x", resumeMask);
-
-        streamMask &= ~resumeMask;
-
-        mFetcherInfos.valueAt(i).mFetcher->startAsync(
-                audioSource, videoSource, subtitleSource);
     }
 
     // streamMask now only contains the types that need a new fetcher created.
@@ -1039,52 +1169,65 @@ void LiveSession::onChangeConfiguration3(const sp<AMessage> &msg) {
         ALOGV("creating new fetchers for mask 0x%08x", streamMask);
     }
 
-    while (streamMask != 0) {
-        StreamType streamType = (StreamType)(streamMask & ~(streamMask - 1));
+    // Find out when the original fetchers have buffered up to and start the new fetchers
+    // at a later timestamp.
+    for (size_t i = 0; i < kMaxStreams; i++) {
+        if (!(indexToType(i) & streamMask)) {
+            continue;
+        }
 
         AString uri;
-        switch (streamType) {
-            case STREAMTYPE_AUDIO:
-                uri = audioURI;
-                break;
-            case STREAMTYPE_VIDEO:
-                uri = videoURI;
-                break;
-            case STREAMTYPE_SUBTITLES:
-                uri = subtitleURI;
-                break;
-            default:
-                TRESPASS();
-        }
+        uri = mStreams[i].mUri;
 
         sp<PlaylistFetcher> fetcher = addFetcher(uri.c_str());
         CHECK(fetcher != NULL);
 
-        sp<AnotherPacketSource> audioSource;
-        if ((streamMask & STREAMTYPE_AUDIO) && uri == audioURI) {
-            audioSource = mPacketSources.valueFor(STREAMTYPE_AUDIO);
-            audioSource->clear();
-
-            streamMask &= ~STREAMTYPE_AUDIO;
-        }
-
-        sp<AnotherPacketSource> videoSource;
-        if ((streamMask & STREAMTYPE_VIDEO) && uri == videoURI) {
-            videoSource = mPacketSources.valueFor(STREAMTYPE_VIDEO);
-            videoSource->clear();
-
-            streamMask &= ~STREAMTYPE_VIDEO;
-        }
+        int32_t latestSeq = -1;
+        int64_t latestTimeUs = 0ll;
+        sp<AnotherPacketSource> sources[kMaxStreams];
+
+        // TRICKY: looping from i as earlier streams are already removed from streamMask
+        for (size_t j = i; j < kMaxStreams; ++j) {
+            if ((streamMask & indexToType(j)) && uri == mStreams[j].mUri) {
+                sources[j] = mPacketSources.valueFor(indexToType(j));
+
+                if (!switching) {
+                    sources[j]->clear();
+                } else {
+                    int32_t type, seq;
+                    int64_t srcTimeUs;
+                    sp<AMessage> meta = sources[j]->getLatestMeta();
+
+                    if (meta != NULL && !meta->findInt32("discontinuity", &type)) {
+                        CHECK(meta->findInt32("seq", &seq));
+                        if (seq > latestSeq) {
+                            latestSeq = seq;
+                        }
+                        CHECK(meta->findInt64("timeUs", &srcTimeUs));
+                        if (srcTimeUs > latestTimeUs) {
+                            latestTimeUs = srcTimeUs;
+                        }
+                    }
 
-        sp<AnotherPacketSource> subtitleSource;
-        if ((streamMask & STREAMTYPE_SUBTITLES) && uri == subtitleURI) {
-            subtitleSource = mPacketSources.valueFor(STREAMTYPE_SUBTITLES);
-            subtitleSource->clear();
+                    sources[j] = mPacketSources2.valueFor(indexToType(j));
+                    sources[j]->clear();
+                    uint32_t extraStreams = mNewStreamMask & (~mStreamMask);
+                    if (extraStreams & indexToType(j)) {
+                        sources[j]->queueAccessUnit(createFormatChangeBuffer(/* swap = */ false));
+                    }
+                }
 
-            streamMask &= ~STREAMTYPE_SUBTITLES;
+                streamMask &= ~indexToType(j);
+            }
         }
 
-        fetcher->startAsync(audioSource, videoSource, subtitleSource, timeUs);
+        fetcher->startAsync(
+                sources[kAudioIndex],
+                sources[kVideoIndex],
+                sources[kSubtitleIndex],
+                timeUs,
+                latestTimeUs /* min start time(us) */,
+                latestSeq >= 0 ? latestSeq + 1 : -1 /* starting sequence number hint */ );
     }
 
     // All fetchers have now been started, the configuration change
@@ -1093,14 +1236,61 @@ void LiveSession::onChangeConfiguration3(const sp<AMessage> &msg) {
     scheduleCheckBandwidthEvent();
 
     ALOGV("XXX configuration change completed.");
-
     mReconfigurationInProgress = false;
+    if (switching) {
+        mSwitchInProgress = true;
+    } else {
+        mStreamMask = mNewStreamMask;
+    }
 
     if (mDisconnectReplyID != 0) {
         finishDisconnect();
     }
 }
 
+void LiveSession::onSwapped(const sp<AMessage> &msg) {
+    int32_t switchGeneration;
+    CHECK(msg->findInt32("switchGeneration", &switchGeneration));
+    if (switchGeneration != mSwitchGeneration) {
+        return;
+    }
+
+    int32_t stream;
+    CHECK(msg->findInt32("stream", &stream));
+    mSwapMask |= stream;
+    if (mSwapMask != mStreamMask) {
+        return;
+    }
+
+    // Check if new variant contains extra streams.
+    uint32_t extraStreams = mNewStreamMask & (~mStreamMask);
+    while (extraStreams) {
+        StreamType extraStream = (StreamType) (extraStreams & ~(extraStreams - 1));
+        swapPacketSource(extraStream);
+        extraStreams &= ~extraStream;
+    }
+
+    tryToFinishBandwidthSwitch();
+}
+
+// Mark switch done when:
+//   1. all old buffers are swapped out, AND
+//   2. all old fetchers are removed.
+void LiveSession::tryToFinishBandwidthSwitch() {
+    bool needToRemoveFetchers = false;
+    for (size_t i = 0; i < mFetcherInfos.size(); ++i) {
+        if (mFetcherInfos.valueAt(i).mToBeRemoved) {
+            needToRemoveFetchers = true;
+            break;
+        }
+    }
+    if (!needToRemoveFetchers && mSwapMask == mStreamMask) {
+        mStreamMask = mNewStreamMask;
+        mSwitchInProgress = false;
+        mSwapMask = 0;
+    }
+}
+
 void LiveSession::scheduleCheckBandwidthEvent() {
     sp<AMessage> msg = new AMessage(kWhatCheckBandwidth, id());
     msg->setInt32("generation", mCheckBandwidthGeneration);
@@ -1111,16 +1301,37 @@ void LiveSession::cancelCheckBandwidthEvent() {
     ++mCheckBandwidthGeneration;
 }
 
-void LiveSession::onCheckBandwidth() {
-    if (mReconfigurationInProgress) {
-        scheduleCheckBandwidthEvent();
-        return;
+void LiveSession::cancelBandwidthSwitch() {
+    Mutex::Autolock lock(mSwapMutex);
+    mSwitchGeneration++;
+    mSwitchInProgress = false;
+    mSwapMask = 0;
+}
+
+bool LiveSession::canSwitchBandwidthTo(size_t bandwidthIndex) {
+    if (mReconfigurationInProgress || mSwitchInProgress) {
+        return false;
     }
 
+    if (mPrevBandwidthIndex < 0) {
+        return true;
+    }
+
+    if (bandwidthIndex == (size_t)mPrevBandwidthIndex) {
+        return false;
+    } else if (bandwidthIndex > (size_t)mPrevBandwidthIndex) {
+        return canSwitchUp();
+    } else {
+        return true;
+    }
+}
+
+void LiveSession::onCheckBandwidth() {
     size_t bandwidthIndex = getBandwidthIndex();
-    if (mPrevBandwidthIndex < 0
-            || bandwidthIndex != (size_t)mPrevBandwidthIndex) {
+    if (canSwitchBandwidthTo(bandwidthIndex)) {
         changeConfiguration(-1ll /* timeUs */, bandwidthIndex);
+    } else {
+        scheduleCheckBandwidthEvent();
     }
 
     // Handling the kWhatCheckBandwidth even here does _not_ automatically
diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index 8f6a4ea..3f8fee5 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -42,10 +42,17 @@ struct LiveSession : public AHandler {
             const sp<AMessage> &notify,
             uint32_t flags = 0, bool uidValid = false, uid_t uid = 0);
 
+    enum StreamIndex {
+        kAudioIndex    = 0,
+        kVideoIndex    = 1,
+        kSubtitleIndex = 2,
+        kMaxStreams    = 3,
+    };
+
     enum StreamType {
-        STREAMTYPE_AUDIO        = 1,
-        STREAMTYPE_VIDEO        = 2,
-        STREAMTYPE_SUBTITLES    = 4,
+        STREAMTYPE_AUDIO        = 1 << kAudioIndex,
+        STREAMTYPE_VIDEO        = 1 << kVideoIndex,
+        STREAMTYPE_SUBTITLES    = 1 << kSubtitleIndex,
     };
     status_t dequeueAccessUnit(StreamType stream, sp<ABuffer> *accessUnit);
 
@@ -74,6 +81,11 @@ struct LiveSession : public AHandler {
         kWhatPreparationFailed,
     };
 
+    // create a format-change discontinuity
+    //
+    // swap:
+    //   whether is format-change discontinuity should trigger a buffer swap
+    sp<ABuffer> createFormatChangeBuffer(bool swap = true);
 protected:
     virtual ~LiveSession();
 
@@ -92,6 +104,7 @@ private:
         kWhatChangeConfiguration2       = 'chC2',
         kWhatChangeConfiguration3       = 'chC3',
         kWhatFinishDisconnect2          = 'fin2',
+        kWhatSwapped                    = 'swap',
     };
 
     struct BandwidthItem {
@@ -103,8 +116,22 @@ private:
         sp<PlaylistFetcher> mFetcher;
         int64_t mDurationUs;
         bool mIsPrepared;
+        bool mToBeRemoved;
     };
 
+    struct StreamItem {
+        const char *mType;
+        AString mUri;
+        StreamItem() : mType("") {}
+        StreamItem(const char *type) : mType(type) {}
+        AString uriKey() {
+            AString key(mType);
+            key.append("URI");
+            return key;
+        }
+    };
+    StreamItem mStreams[kMaxStreams];
+
     sp<AMessage> mNotify;
     uint32_t mFlags;
     bool mUIDValid;
@@ -123,21 +150,40 @@ private:
     sp<M3UParser> mPlaylist;
 
     KeyedVector<AString, FetcherInfo> mFetcherInfos;
-    AString mAudioURI, mVideoURI, mSubtitleURI;
     uint32_t mStreamMask;
 
+    // Masks used during reconfiguration:
+    // mNewStreamMask: streams in the variant playlist we're switching to;
+    // we don't want to immediately overwrite the original value.
+    uint32_t mNewStreamMask;
+
+    // mSwapMask: streams that have started to playback content in the new variant playlist;
+    // we use this to track reconfiguration progress.
+    uint32_t mSwapMask;
+
     KeyedVector<StreamType, sp<AnotherPacketSource> > mPacketSources;
+    // A second set of packet sources that buffer content for the variant we're switching to.
+    KeyedVector<StreamType, sp<AnotherPacketSource> > mPacketSources2;
+
+    // A mutex used to serialize two sets of events:
+    // * the swapping of packet sources in dequeueAccessUnit on the player thread, AND
+    // * a forced bandwidth switch termination in cancelSwitch on the live looper.
+    Mutex mSwapMutex;
 
     int32_t mCheckBandwidthGeneration;
+    int32_t mSwitchGeneration;
 
     size_t mContinuationCounter;
     sp<AMessage> mContinuation;
+    sp<AMessage> mSeekReply;
 
     int64_t mLastDequeuedTimeUs;
     int64_t mRealTimeBaseUs;
 
     bool mReconfigurationInProgress;
+    bool mSwitchInProgress;
     uint32_t mDisconnectReplyID;
+    uint32_t mSeekReplyID;
 
     sp<PlaylistFetcher> addFetcher(const char *uri);
 
@@ -145,9 +191,25 @@ private:
     status_t onSeek(const sp<AMessage> &msg);
     void onFinishDisconnect2();
 
-    status_t fetchFile(
+    // If given a non-zero block_size (default 0), it is used to cap the number of
+    // bytes read in from the DataSource. If given a non-NULL buffer, new content
+    // is read into the end.
+    //
+    // The DataSource we read from is responsible for signaling error or EOF to help us
+    // break out of the read loop. The DataSource can be returned to the caller, so
+    // that the caller can reuse it for subsequent fetches (within the initially
+    // requested range).
+    //
+    // For reused HTTP sources, the caller must download a file sequentially without
+    // any overlaps or gaps to prevent reconnection.
+    ssize_t fetchFile(
             const char *url, sp<ABuffer> *out,
+            /* request/open a file starting at range_offset for range_length bytes */
             int64_t range_offset = 0, int64_t range_length = -1,
+            /* download block size */
+            uint32_t block_size = 0,
+            /* reuse DataSource if doing partial fetch */
+            sp<DataSource> *source = NULL,
             String8 *actualUrl = NULL);
 
     sp<M3UParser> fetchPlaylist(
@@ -156,22 +218,34 @@ private:
     size_t getBandwidthIndex();
 
     static int SortByBandwidth(const BandwidthItem *, const BandwidthItem *);
+    static StreamType indexToType(int idx);
 
     void changeConfiguration(
             int64_t timeUs, size_t bandwidthIndex, bool pickTrack = false);
     void onChangeConfiguration(const sp<AMessage> &msg);
     void onChangeConfiguration2(const sp<AMessage> &msg);
     void onChangeConfiguration3(const sp<AMessage> &msg);
+    void onSwapped(const sp<AMessage> &msg);
+    void tryToFinishBandwidthSwitch();
 
     void scheduleCheckBandwidthEvent();
     void cancelCheckBandwidthEvent();
 
+    // cancelBandwidthSwitch is atomic wrt swapPacketSource; call it to prevent packet sources
+    // from being swapped out on stale discontinuities while manipulating
+    // mPacketSources/mPacketSources2.
+    void cancelBandwidthSwitch();
+
+    bool canSwitchBandwidthTo(size_t bandwidthIndex);
     void onCheckBandwidth();
 
     void finishDisconnect();
 
     void postPrepared(status_t err);
 
+    void swapPacketSource(StreamType stream);
+    bool canSwitchUp();
+
     DISALLOW_EVIL_CONSTRUCTORS(LiveSession);
 };
 
diff --git a/media/libstagefright/httplive/M3UParser.cpp b/media/libstagefright/httplive/M3UParser.cpp
index b2a7010..20c3a76 100644
--- a/media/libstagefright/httplive/M3UParser.cpp
+++ b/media/libstagefright/httplive/M3UParser.cpp
@@ -24,6 +24,7 @@
 #include <media/stagefright/foundation/ADebug.h>
 #include <media/stagefright/foundation/AMessage.h>
 #include <media/stagefright/MediaErrors.h>
+#include <media/stagefright/Utils.h>
 #include <media/mediaplayer.h>
 
 namespace android {
@@ -352,9 +353,28 @@ bool M3UParser::getTypeURI(size_t index, const char *key, AString *uri) const {
     if (!meta->findString(key, &groupID)) {
         *uri = mItems.itemAt(index).mURI;
 
-        // Assume media without any more specific attribute contains
-        // audio and video, but no subtitles.
-        return !strcmp("audio", key) || !strcmp("video", key);
+        AString codecs;
+        if (!meta->findString("codecs", &codecs)) {
+            // Assume media without any more specific attribute contains
+            // audio and video, but no subtitles.
+            return !strcmp("audio", key) || !strcmp("video", key);
+        } else {
+            // Split the comma separated list of codecs.
+            size_t offset = 0;
+            ssize_t commaPos = -1;
+            codecs.append(',');
+            while ((commaPos = codecs.find(",", offset)) >= 0) {
+                AString codec(codecs, offset, commaPos - offset);
+                codec.trim();
+                // return true only if a codec of type `key` ("audio"/"video")
+                // is found.
+                if (codecIsType(codec, key)) {
+                    return true;
+                }
+                offset = commaPos + 1;
+            }
+            return false;
+        }
     }
 
     sp<MediaGroup> group = mMediaGroups.valueFor(groupID);
@@ -369,18 +389,6 @@ bool M3UParser::getTypeURI(size_t index, const char *key, AString *uri) const {
     return true;
 }
 
-bool M3UParser::getAudioURI(size_t index, AString *uri) const {
-    return getTypeURI(index, "audio", uri);
-}
-
-bool M3UParser::getVideoURI(size_t index, AString *uri) const {
-    return getTypeURI(index, "video", uri);
-}
-
-bool M3UParser::getSubtitleURI(size_t index, AString *uri) const {
-    return getTypeURI(index, "subtitles", uri);
-}
-
 static bool MakeURL(const char *baseURL, const char *url, AString *out) {
     out->clear();
 
@@ -694,12 +702,22 @@ status_t M3UParser::parseStreamInf(
                 *meta = new AMessage;
             }
             (*meta)->setInt32("bandwidth", x);
+        } else if (!strcasecmp("codecs", key.c_str())) {
+            if (!isQuotedString(val)) {
+                ALOGE("Expected quoted string for %s attribute, "
+                      "got '%s' instead.",
+                      key.c_str(), val.c_str());;
+
+                return ERROR_MALFORMED;
+            }
+
+            key.tolower();
+            const AString &codecs = unquoteString(val);
+            (*meta)->setString(key.c_str(), codecs.c_str());
         } else if (!strcasecmp("audio", key.c_str())
                 || !strcasecmp("video", key.c_str())
                 || !strcasecmp("subtitles", key.c_str())) {
-            if (val.size() < 2
-                    || val.c_str()[0] != '"'
-                    || val.c_str()[val.size() - 1] != '"') {
+            if (!isQuotedString(val)) {
                 ALOGE("Expected quoted string for %s attribute, "
                       "got '%s' instead.",
                       key.c_str(), val.c_str());
@@ -707,7 +725,7 @@ status_t M3UParser::parseStreamInf(
                 return ERROR_MALFORMED;
             }
 
-            AString groupID(val, 1, val.size() - 2);
+            const AString &groupID = unquoteString(val);
             ssize_t groupIndex = mMediaGroups.indexOfKey(groupID);
 
             if (groupIndex < 0) {
@@ -1095,4 +1113,121 @@ status_t M3UParser::ParseDouble(const char *s, double *x) {
     return OK;
 }
 
+// static
+bool M3UParser::isQuotedString(const AString &str) {
+    if (str.size() < 2
+            || str.c_str()[0] != '"'
+            || str.c_str()[str.size() - 1] != '"') {
+        return false;
+    }
+    return true;
+}
+
+// static
+AString M3UParser::unquoteString(const AString &str) {
+     if (!isQuotedString(str)) {
+         return str;
+     }
+     return AString(str, 1, str.size() - 2);
+}
+
+// static
+bool M3UParser::codecIsType(const AString &codec, const char *type) {
+    if (codec.size() < 4) {
+        return false;
+    }
+    const char *c = codec.c_str();
+    switch (FOURCC(c[0], c[1], c[2], c[3])) {
+        // List extracted from http://www.mp4ra.org/codecs.html
+        case 'ac-3':
+        case 'alac':
+        case 'dra1':
+        case 'dtsc':
+        case 'dtse':
+        case 'dtsh':
+        case 'dtsl':
+        case 'ec-3':
+        case 'enca':
+        case 'g719':
+        case 'g726':
+        case 'm4ae':
+        case 'mlpa':
+        case 'mp4a':
+        case 'raw ':
+        case 'samr':
+        case 'sawb':
+        case 'sawp':
+        case 'sevc':
+        case 'sqcp':
+        case 'ssmv':
+        case 'twos':
+        case 'agsm':
+        case 'alaw':
+        case 'dvi ':
+        case 'fl32':
+        case 'fl64':
+        case 'ima4':
+        case 'in24':
+        case 'in32':
+        case 'lpcm':
+        case 'Qclp':
+        case 'QDM2':
+        case 'QDMC':
+        case 'ulaw':
+        case 'vdva':
+            return !strcmp("audio", type);
+
+        case 'avc1':
+        case 'avc2':
+        case 'avcp':
+        case 'drac':
+        case 'encv':
+        case 'mjp2':
+        case 'mp4v':
+        case 'mvc1':
+        case 'mvc2':
+        case 'resv':
+        case 's263':
+        case 'svc1':
+        case 'vc-1':
+        case 'CFHD':
+        case 'civd':
+        case 'DV10':
+        case 'dvh5':
+        case 'dvh6':
+        case 'dvhp':
+        case 'DVOO':
+        case 'DVOR':
+        case 'DVTV':
+        case 'DVVT':
+        case 'flic':
+        case 'gif ':
+        case 'h261':
+        case 'h263':
+        case 'HD10':
+        case 'jpeg':
+        case 'M105':
+        case 'mjpa':
+        case 'mjpb':
+        case 'png ':
+        case 'PNTG':
+        case 'rle ':
+        case 'rpza':
+        case 'Shr0':
+        case 'Shr1':
+        case 'Shr2':
+        case 'Shr3':
+        case 'Shr4':
+        case 'SVQ1':
+        case 'SVQ3':
+        case 'tga ':
+        case 'tiff':
+        case 'WRLE':
+            return !strcmp("video", type);
+
+        default:
+            return false;
+    }
+}
+
 }  // namespace android
diff --git a/media/libstagefright/httplive/M3UParser.h b/media/libstagefright/httplive/M3UParser.h
index 5248004..ccd6556 100644
--- a/media/libstagefright/httplive/M3UParser.h
+++ b/media/libstagefright/httplive/M3UParser.h
@@ -45,9 +45,7 @@ struct M3UParser : public RefBase {
     status_t getTrackInfo(Parcel* reply) const;
     ssize_t getSelectedIndex() const;
 
-    bool getAudioURI(size_t index, AString *uri) const;
-    bool getVideoURI(size_t index, AString *uri) const;
-    bool getSubtitleURI(size_t index, AString *uri) const;
+    bool getTypeURI(size_t index, const char *key, AString *uri) const;
 
 protected:
     virtual ~M3UParser();
@@ -95,11 +93,13 @@ private:
 
     status_t parseMedia(const AString &line);
 
-    bool getTypeURI(size_t index, const char *key, AString *uri) const;
-
     static status_t ParseInt32(const char *s, int32_t *x);
     static status_t ParseDouble(const char *s, double *x);
 
+    static bool isQuotedString(const AString &str);
+    static AString unquoteString(const AString &str);
+    static bool codecIsType(const AString &codec, const char *type);
+
     DISALLOW_EVIL_CONSTRUCTORS(M3UParser);
 };
 
diff --git a/media/libstagefright/httplive/PlaylistFetcher.cpp b/media/libstagefright/httplive/PlaylistFetcher.cpp
index 57bf7db..513f114 100644
--- a/media/libstagefright/httplive/PlaylistFetcher.cpp
+++ b/media/libstagefright/httplive/PlaylistFetcher.cpp
@@ -48,26 +48,35 @@ namespace android {
 
 // static
 const int64_t PlaylistFetcher::kMinBufferedDurationUs = 10000000ll;
+const int64_t PlaylistFetcher::kMaxMonitorDelayUs = 3000000ll;
+const int32_t PlaylistFetcher::kDownloadBlockSize = 192;
+const int32_t PlaylistFetcher::kNumSkipFrames = 10;
 
 PlaylistFetcher::PlaylistFetcher(
         const sp<AMessage> &notify,
         const sp<LiveSession> &session,
         const char *uri)
     : mNotify(notify),
+      mStartTimeUsNotify(notify->dup()),
       mSession(session),
       mURI(uri),
       mStreamTypeMask(0),
       mStartTimeUs(-1ll),
+      mMinStartTimeUs(0ll),
+      mStopParams(NULL),
       mLastPlaylistFetchTimeUs(-1ll),
       mSeqNumber(-1),
       mNumRetries(0),
       mStartup(true),
+      mPrepared(false),
       mNextPTSTimeUs(-1ll),
       mMonitorQueueGeneration(0),
       mRefreshState(INITIAL_MINIMUM_RELOAD_DELAY),
       mFirstPTSValid(false),
       mAbsoluteTimeAnchorUs(0ll) {
     memset(mPlaylistHash, 0, sizeof(mPlaylistHash));
+    mStartTimeUsNotify->setInt32("what", kWhatStartedAt);
+    mStartTimeUsNotify->setInt32("streamMask", 0);
 }
 
 PlaylistFetcher::~PlaylistFetcher() {
@@ -104,10 +113,16 @@ int64_t PlaylistFetcher::getSegmentStartTimeUs(int32_t seqNumber) const {
     return segmentStartUs;
 }
 
-bool PlaylistFetcher::timeToRefreshPlaylist(int64_t nowUs) const {
-    if (mPlaylist == NULL) {
+int64_t PlaylistFetcher::delayUsToRefreshPlaylist() const {
+    int64_t nowUs = ALooper::GetNowUs();
+
+    if (mPlaylist == NULL || mLastPlaylistFetchTimeUs < 0ll) {
         CHECK_EQ((int)mRefreshState, (int)INITIAL_MINIMUM_RELOAD_DELAY);
-        return true;
+        return 0ll;
+    }
+
+    if (mPlaylist->isComplete()) {
+        return (~0llu >> 1);
     }
 
     int32_t targetDurationSecs;
@@ -158,11 +173,13 @@ bool PlaylistFetcher::timeToRefreshPlaylist(int64_t nowUs) const {
             break;
     }
 
-    return mLastPlaylistFetchTimeUs + minPlaylistAgeUs <= nowUs;
+    int64_t delayUs = mLastPlaylistFetchTimeUs + minPlaylistAgeUs - nowUs;
+    return delayUs > 0ll ? delayUs : 0ll;
 }
 
 status_t PlaylistFetcher::decryptBuffer(
-        size_t playlistIndex, const sp<ABuffer> &buffer) {
+        size_t playlistIndex, const sp<ABuffer> &buffer,
+        bool first) {
     sp<AMessage> itemMeta;
     bool found = false;
     AString method;
@@ -180,6 +197,7 @@ status_t PlaylistFetcher::decryptBuffer(
     if (!found) {
         method = "NONE";
     }
+    buffer->meta()->setString("cipher-method", method.c_str());
 
     if (method == "NONE") {
         return OK;
@@ -200,9 +218,9 @@ status_t PlaylistFetcher::decryptBuffer(
     if (index >= 0) {
         key = mAESKeyForURI.valueAt(index);
     } else {
-        status_t err = mSession->fetchFile(keyURI.c_str(), &key);
+        ssize_t err = mSession->fetchFile(keyURI.c_str(), &key);
 
-        if (err != OK) {
+        if (err < 0) {
             ALOGE("failed to fetch cipher key from '%s'.", keyURI.c_str());
             return ERROR_IO;
         } else if (key->size() != 16) {
@@ -219,63 +237,89 @@ status_t PlaylistFetcher::decryptBuffer(
         return UNKNOWN_ERROR;
     }
 
-    unsigned char aes_ivec[16];
+    size_t n = buffer->size();
+    if (!n) {
+        return OK;
+    }
+    CHECK(n % 16 == 0);
 
-    AString iv;
-    if (itemMeta->findString("cipher-iv", &iv)) {
-        if ((!iv.startsWith("0x") && !iv.startsWith("0X"))
-                || iv.size() != 16 * 2 + 2) {
-            ALOGE("malformed cipher IV '%s'.", iv.c_str());
-            return ERROR_MALFORMED;
-        }
+    if (first) {
+        // If decrypting the first block in a file, read the iv from the manifest
+        // or derive the iv from the file's sequence number.
 
-        memset(aes_ivec, 0, sizeof(aes_ivec));
-        for (size_t i = 0; i < 16; ++i) {
-            char c1 = tolower(iv.c_str()[2 + 2 * i]);
-            char c2 = tolower(iv.c_str()[3 + 2 * i]);
-            if (!isxdigit(c1) || !isxdigit(c2)) {
+        AString iv;
+        if (itemMeta->findString("cipher-iv", &iv)) {
+            if ((!iv.startsWith("0x") && !iv.startsWith("0X"))
+                    || iv.size() != 16 * 2 + 2) {
                 ALOGE("malformed cipher IV '%s'.", iv.c_str());
                 return ERROR_MALFORMED;
             }
-            uint8_t nibble1 = isdigit(c1) ? c1 - '0' : c1 - 'a' + 10;
-            uint8_t nibble2 = isdigit(c2) ? c2 - '0' : c2 - 'a' + 10;
 
-            aes_ivec[i] = nibble1 << 4 | nibble2;
+            memset(mAESInitVec, 0, sizeof(mAESInitVec));
+            for (size_t i = 0; i < 16; ++i) {
+                char c1 = tolower(iv.c_str()[2 + 2 * i]);
+                char c2 = tolower(iv.c_str()[3 + 2 * i]);
+                if (!isxdigit(c1) || !isxdigit(c2)) {
+                    ALOGE("malformed cipher IV '%s'.", iv.c_str());
+                    return ERROR_MALFORMED;
+                }
+                uint8_t nibble1 = isdigit(c1) ? c1 - '0' : c1 - 'a' + 10;
+                uint8_t nibble2 = isdigit(c2) ? c2 - '0' : c2 - 'a' + 10;
+
+                mAESInitVec[i] = nibble1 << 4 | nibble2;
+            }
+        } else {
+            memset(mAESInitVec, 0, sizeof(mAESInitVec));
+            mAESInitVec[15] = mSeqNumber & 0xff;
+            mAESInitVec[14] = (mSeqNumber >> 8) & 0xff;
+            mAESInitVec[13] = (mSeqNumber >> 16) & 0xff;
+            mAESInitVec[12] = (mSeqNumber >> 24) & 0xff;
         }
-    } else {
-        memset(aes_ivec, 0, sizeof(aes_ivec));
-        aes_ivec[15] = mSeqNumber & 0xff;
-        aes_ivec[14] = (mSeqNumber >> 8) & 0xff;
-        aes_ivec[13] = (mSeqNumber >> 16) & 0xff;
-        aes_ivec[12] = (mSeqNumber >> 24) & 0xff;
     }
 
     AES_cbc_encrypt(
             buffer->data(), buffer->data(), buffer->size(),
-            &aes_key, aes_ivec, AES_DECRYPT);
-
-    // hexdump(buffer->data(), buffer->size());
+            &aes_key, mAESInitVec, AES_DECRYPT);
 
-    size_t n = buffer->size();
-    CHECK_GT(n, 0u);
+    return OK;
+}
 
-    size_t pad = buffer->data()[n - 1];
+status_t PlaylistFetcher::checkDecryptPadding(const sp<ABuffer> &buffer) {
+    status_t err;
+    AString method;
+    CHECK(buffer->meta()->findString("cipher-method", &method));
+    if (method == "NONE") {
+        return OK;
+    }
 
-    CHECK_GT(pad, 0u);
-    CHECK_LE(pad, 16u);
-    CHECK_GE((size_t)n, pad);
-    for (size_t i = 0; i < pad; ++i) {
-        CHECK_EQ((unsigned)buffer->data()[n - 1 - i], pad);
+    uint8_t padding = 0;
+    if (buffer->size() > 0) {
+        padding = buffer->data()[buffer->size() - 1];
     }
 
-    n -= pad;
+    if (padding > 16) {
+        return ERROR_MALFORMED;
+    }
 
-    buffer->setRange(buffer->offset(), n);
+    for (size_t i = buffer->size() - padding; i < padding; i++) {
+        if (buffer->data()[i] != padding) {
+            return ERROR_MALFORMED;
+        }
+    }
 
+    buffer->setRange(buffer->offset(), buffer->size() - padding);
     return OK;
 }
 
-void PlaylistFetcher::postMonitorQueue(int64_t delayUs) {
+void PlaylistFetcher::postMonitorQueue(int64_t delayUs, int64_t minDelayUs) {
+    int64_t maxDelayUs = delayUsToRefreshPlaylist();
+    if (maxDelayUs < minDelayUs) {
+        maxDelayUs = minDelayUs;
+    }
+    if (delayUs > maxDelayUs) {
+        ALOGV("Need to refresh playlist in %lld", maxDelayUs);
+        delayUs = maxDelayUs;
+    }
     sp<AMessage> msg = new AMessage(kWhatMonitorQueue, id());
     msg->setInt32("generation", mMonitorQueueGeneration);
     msg->post(delayUs);
@@ -289,7 +333,9 @@ void PlaylistFetcher::startAsync(
         const sp<AnotherPacketSource> &audioSource,
         const sp<AnotherPacketSource> &videoSource,
         const sp<AnotherPacketSource> &subtitleSource,
-        int64_t startTimeUs) {
+        int64_t startTimeUs,
+        int64_t minStartTimeUs,
+        int32_t startSeqNumberHint) {
     sp<AMessage> msg = new AMessage(kWhatStart, id());
 
     uint32_t streamTypeMask = 0ul;
@@ -311,6 +357,8 @@ void PlaylistFetcher::startAsync(
 
     msg->setInt32("streamTypeMask", streamTypeMask);
     msg->setInt64("startTimeUs", startTimeUs);
+    msg->setInt64("minStartTimeUs", minStartTimeUs);
+    msg->setInt32("startSeqNumberHint", startSeqNumberHint);
     msg->post();
 }
 
@@ -318,8 +366,16 @@ void PlaylistFetcher::pauseAsync() {
     (new AMessage(kWhatPause, id()))->post();
 }
 
-void PlaylistFetcher::stopAsync() {
-    (new AMessage(kWhatStop, id()))->post();
+void PlaylistFetcher::stopAsync(bool selfTriggered) {
+    sp<AMessage> msg = new AMessage(kWhatStop, id());
+    msg->setInt32("selfTriggered", selfTriggered);
+    msg->post();
+}
+
+void PlaylistFetcher::resumeUntilAsync(const sp<AMessage> &params) {
+    AMessage* msg = new AMessage(kWhatResumeUntil, id());
+    msg->setMessage("params", params);
+    msg->post();
 }
 
 void PlaylistFetcher::onMessageReceived(const sp<AMessage> &msg) {
@@ -347,7 +403,7 @@ void PlaylistFetcher::onMessageReceived(const sp<AMessage> &msg) {
 
         case kWhatStop:
         {
-            onStop();
+            onStop(msg);
 
             sp<AMessage> notify = mNotify->dup();
             notify->setInt32("what", kWhatStopped);
@@ -356,6 +412,7 @@ void PlaylistFetcher::onMessageReceived(const sp<AMessage> &msg) {
         }
 
         case kWhatMonitorQueue:
+        case kWhatDownloadNext:
         {
             int32_t generation;
             CHECK(msg->findInt32("generation", &generation));
@@ -365,7 +422,17 @@ void PlaylistFetcher::onMessageReceived(const sp<AMessage> &msg) {
                 break;
             }
 
-            onMonitorQueue();
+            if (msg->what() == kWhatMonitorQueue) {
+                onMonitorQueue();
+            } else {
+                onDownloadNext();
+            }
+            break;
+        }
+
+        case kWhatResumeUntil:
+        {
+            onResumeUntil(msg);
             break;
         }
 
@@ -381,7 +448,10 @@ status_t PlaylistFetcher::onStart(const sp<AMessage> &msg) {
     CHECK(msg->findInt32("streamTypeMask", (int32_t *)&streamTypeMask));
 
     int64_t startTimeUs;
+    int32_t startSeqNumberHint;
     CHECK(msg->findInt64("startTimeUs", &startTimeUs));
+    CHECK(msg->findInt64("minStartTimeUs", (int64_t *) &mMinStartTimeUs));
+    CHECK(msg->findInt32("startSeqNumberHint", &startSeqNumberHint));
 
     if (streamTypeMask & LiveSession::STREAMTYPE_AUDIO) {
         void *ptr;
@@ -416,6 +486,11 @@ status_t PlaylistFetcher::onStart(const sp<AMessage> &msg) {
     if (mStartTimeUs >= 0ll) {
         mSeqNumber = -1;
         mStartup = true;
+        mPrepared = false;
+    }
+
+    if (startSeqNumberHint >= 0) {
+        mSeqNumber = startSeqNumberHint;
     }
 
     postMonitorQueue();
@@ -425,22 +500,83 @@ status_t PlaylistFetcher::onStart(const sp<AMessage> &msg) {
 
 void PlaylistFetcher::onPause() {
     cancelMonitorQueue();
-
-    mPacketSources.clear();
-    mStreamTypeMask = 0;
 }
 
-void PlaylistFetcher::onStop() {
+void PlaylistFetcher::onStop(const sp<AMessage> &msg) {
     cancelMonitorQueue();
 
-    for (size_t i = 0; i < mPacketSources.size(); ++i) {
-        mPacketSources.valueAt(i)->clear();
+    int32_t selfTriggered;
+    CHECK(msg->findInt32("selfTriggered", &selfTriggered));
+    if (!selfTriggered) {
+        // Self triggered stops only happen during switching, in which case we do not want
+        // to clear the discontinuities queued at the end of packet sources.
+        for (size_t i = 0; i < mPacketSources.size(); i++) {
+            sp<AnotherPacketSource> packetSource = mPacketSources.valueAt(i);
+            packetSource->clear();
+        }
     }
 
     mPacketSources.clear();
     mStreamTypeMask = 0;
 }
 
+// Resume until we have reached the boundary timestamps listed in `msg`; when
+// the remaining time is too short (within a resume threshold) stop immediately
+// instead.
+status_t PlaylistFetcher::onResumeUntil(const sp<AMessage> &msg) {
+    sp<AMessage> params;
+    CHECK(msg->findMessage("params", &params));
+
+    bool stop = false;
+    for (size_t i = 0; i < mPacketSources.size(); i++) {
+        sp<AnotherPacketSource> packetSource = mPacketSources.valueAt(i);
+
+        const char *stopKey;
+        int streamType = mPacketSources.keyAt(i);
+        switch (streamType) {
+        case LiveSession::STREAMTYPE_VIDEO:
+            stopKey = "timeUsVideo";
+            break;
+
+        case LiveSession::STREAMTYPE_AUDIO:
+            stopKey = "timeUsAudio";
+            break;
+
+        case LiveSession::STREAMTYPE_SUBTITLES:
+            stopKey = "timeUsSubtitle";
+            break;
+
+        default:
+            TRESPASS();
+        }
+
+        // Don't resume if we would stop within a resume threshold.
+        int64_t latestTimeUs = 0, stopTimeUs = 0;
+        sp<AMessage> latestMeta = packetSource->getLatestMeta();
+        if (latestMeta != NULL
+                && (latestMeta->findInt64("timeUs", &latestTimeUs)
+                && params->findInt64(stopKey, &stopTimeUs))) {
+            int64_t diffUs = stopTimeUs - latestTimeUs;
+            if (diffUs < resumeThreshold(latestMeta)) {
+                stop = true;
+            }
+        }
+    }
+
+    if (stop) {
+        for (size_t i = 0; i < mPacketSources.size(); i++) {
+            mPacketSources.valueAt(i)->queueAccessUnit(mSession->createFormatChangeBuffer());
+        }
+        stopAsync(/* selfTriggered = */ true);
+        return OK;
+    }
+
+    mStopParams = params;
+    postMonitorQueue();
+
+    return OK;
+}
+
 void PlaylistFetcher::notifyError(status_t err) {
     sp<AMessage> notify = mNotify->dup();
     notify->setInt32("what", kWhatError);
@@ -457,41 +593,70 @@ void PlaylistFetcher::queueDiscontinuity(
 
 void PlaylistFetcher::onMonitorQueue() {
     bool downloadMore = false;
+    refreshPlaylist();
+
+    int32_t targetDurationSecs;
+    int64_t targetDurationUs = kMinBufferedDurationUs;
+    if (mPlaylist != NULL) {
+        CHECK(mPlaylist->meta()->findInt32("target-duration", &targetDurationSecs));
+        targetDurationUs = targetDurationSecs * 1000000ll;
+    }
 
-    status_t finalResult;
+    // buffer at least 3 times the target duration, or up to 10 seconds
+    int64_t durationToBufferUs = targetDurationUs * 3;
+    if (durationToBufferUs > kMinBufferedDurationUs)  {
+        durationToBufferUs = kMinBufferedDurationUs;
+    }
+
+    int64_t bufferedDurationUs = 0ll;
+    status_t finalResult = NOT_ENOUGH_DATA;
     if (mStreamTypeMask == LiveSession::STREAMTYPE_SUBTITLES) {
         sp<AnotherPacketSource> packetSource =
             mPacketSources.valueFor(LiveSession::STREAMTYPE_SUBTITLES);
 
-        int64_t bufferedDurationUs =
+        bufferedDurationUs =
                 packetSource->getBufferedDurationUs(&finalResult);
-
-        downloadMore = (bufferedDurationUs < kMinBufferedDurationUs);
         finalResult = OK;
     } else {
-        bool first = true;
-        int64_t minBufferedDurationUs = 0ll;
-
+        // Use max stream duration to prevent us from waiting on a non-existent stream;
+        // when we cannot make out from the manifest what streams are included in a playlist
+        // we might assume extra streams.
         for (size_t i = 0; i < mPacketSources.size(); ++i) {
             if ((mStreamTypeMask & mPacketSources.keyAt(i)) == 0) {
                 continue;
             }
 
-            int64_t bufferedDurationUs =
+            int64_t bufferedStreamDurationUs =
                 mPacketSources.valueAt(i)->getBufferedDurationUs(&finalResult);
-
-            if (first || bufferedDurationUs < minBufferedDurationUs) {
-                minBufferedDurationUs = bufferedDurationUs;
-                first = false;
+            ALOGV("buffered %lld for stream %d",
+                    bufferedStreamDurationUs, mPacketSources.keyAt(i));
+            if (bufferedStreamDurationUs > bufferedDurationUs) {
+                bufferedDurationUs = bufferedStreamDurationUs;
             }
         }
+    }
+    downloadMore = (bufferedDurationUs < durationToBufferUs);
+
+    // signal start if buffered up at least the target size
+    if (!mPrepared && bufferedDurationUs > targetDurationUs && downloadMore) {
+        mPrepared = true;
 
-        downloadMore =
-            !first && (minBufferedDurationUs < kMinBufferedDurationUs);
+        ALOGV("prepared, buffered=%lld > %lld",
+                bufferedDurationUs, targetDurationUs);
+        sp<AMessage> msg = mNotify->dup();
+        msg->setInt32("what", kWhatTemporarilyDoneFetching);
+        msg->post();
     }
 
     if (finalResult == OK && downloadMore) {
-        onDownloadNext();
+        ALOGV("monitoring, buffered=%lld < %lld",
+                bufferedDurationUs, durationToBufferUs);
+        // delay the next download slightly; hopefully this gives other concurrent fetchers
+        // a better chance to run.
+        // onDownloadNext();
+        sp<AMessage> msg = new AMessage(kWhatDownloadNext, id());
+        msg->setInt32("generation", mMonitorQueueGeneration);
+        msg->post(1000l);
     } else {
         // Nothing to do yet, try again in a second.
 
@@ -499,15 +664,17 @@ void PlaylistFetcher::onMonitorQueue() {
         msg->setInt32("what", kWhatTemporarilyDoneFetching);
         msg->post();
 
-        postMonitorQueue(1000000ll);
+        int64_t delayUs = mPrepared ? kMaxMonitorDelayUs : targetDurationUs / 2;
+        ALOGV("pausing for %lld, buffered=%lld > %lld",
+                delayUs, bufferedDurationUs, durationToBufferUs);
+        // :TRICKY: need to enforce minimum delay because the delay to
+        // refresh the playlist will become 0
+        postMonitorQueue(delayUs, mPrepared ? targetDurationUs * 2 : 0);
     }
 }
 
-void PlaylistFetcher::onDownloadNext() {
-    int64_t nowUs = ALooper::GetNowUs();
-
-    if (mLastPlaylistFetchTimeUs < 0ll
-            || (!mPlaylist->isComplete() && timeToRefreshPlaylist(nowUs))) {
+status_t PlaylistFetcher::refreshPlaylist() {
+    if (delayUsToRefreshPlaylist() <= 0) {
         bool unchanged;
         sp<M3UParser> playlist = mSession->fetchPlaylist(
                 mURI.c_str(), mPlaylistHash, &unchanged);
@@ -523,7 +690,7 @@ void PlaylistFetcher::onDownloadNext() {
             } else {
                 ALOGE("failed to load playlist at url '%s'", mURI.c_str());
                 notifyError(ERROR_IO);
-                return;
+                return ERROR_IO;
             }
         } else {
             mRefreshState = INITIAL_MINIMUM_RELOAD_DELAY;
@@ -536,6 +703,18 @@ void PlaylistFetcher::onDownloadNext() {
 
         mLastPlaylistFetchTimeUs = ALooper::GetNowUs();
     }
+    return OK;
+}
+
+// static
+bool PlaylistFetcher::bufferStartsWithTsSyncByte(const sp<ABuffer>& buffer) {
+    return buffer->size() > 0 && buffer->data()[0] == 0x47;
+}
+
+void PlaylistFetcher::onDownloadNext() {
+    if (refreshPlaylist() != OK) {
+        return;
+    }
 
     int32_t firstSeqNumberInPlaylist;
     if (mPlaylist->meta() == NULL || !mPlaylist->meta()->findInt32(
@@ -549,17 +728,29 @@ void PlaylistFetcher::onDownloadNext() {
     const int32_t lastSeqNumberInPlaylist =
         firstSeqNumberInPlaylist + (int32_t)mPlaylist->size() - 1;
 
+    if (mStartup && mSeqNumber >= 0
+            && (mSeqNumber < firstSeqNumberInPlaylist || mSeqNumber > lastSeqNumberInPlaylist)) {
+        // in case we guessed wrong during reconfiguration, try fetching the latest content.
+        mSeqNumber = lastSeqNumberInPlaylist;
+    }
+
     if (mSeqNumber < 0) {
         CHECK_GE(mStartTimeUs, 0ll);
 
         if (mPlaylist->isComplete() || mPlaylist->isEvent()) {
             mSeqNumber = getSeqNumberForTime(mStartTimeUs);
+            ALOGV("Initial sequence number for time %lld is %ld from (%ld .. %ld)",
+                    mStartTimeUs, mSeqNumber, firstSeqNumberInPlaylist,
+                    lastSeqNumberInPlaylist);
         } else {
             // If this is a live session, start 3 segments from the end.
             mSeqNumber = lastSeqNumberInPlaylist - 3;
             if (mSeqNumber < firstSeqNumberInPlaylist) {
                 mSeqNumber = firstSeqNumberInPlaylist;
             }
+            ALOGV("Initial sequence number for live event %ld from (%ld .. %ld)",
+                    mSeqNumber, firstSeqNumberInPlaylist,
+                    lastSeqNumberInPlaylist);
         }
 
         mStartTimeUs = -1ll;
@@ -571,16 +762,34 @@ void PlaylistFetcher::onDownloadNext() {
             ++mNumRetries;
 
             if (mSeqNumber > lastSeqNumberInPlaylist) {
-                mLastPlaylistFetchTimeUs = -1;
-                postMonitorQueue(3000000ll);
+                // refresh in increasing fraction (1/2, 1/3, ...) of the
+                // playlist's target duration or 3 seconds, whichever is less
+                int32_t targetDurationSecs;
+                CHECK(mPlaylist->meta()->findInt32(
+                        "target-duration", &targetDurationSecs));
+                int64_t delayUs = mPlaylist->size() * targetDurationSecs *
+                        1000000ll / (1 + mNumRetries);
+                if (delayUs > kMaxMonitorDelayUs) {
+                    delayUs = kMaxMonitorDelayUs;
+                }
+                ALOGV("sequence number high: %ld from (%ld .. %ld), monitor in %lld (retry=%d)",
+                        mSeqNumber, firstSeqNumberInPlaylist,
+                        lastSeqNumberInPlaylist, delayUs, mNumRetries);
+                postMonitorQueue(delayUs);
                 return;
             }
 
             // we've missed the boat, let's start from the lowest sequence
             // number available and signal a discontinuity.
 
-            ALOGI("We've missed the boat, restarting playback.");
-            mSeqNumber = lastSeqNumberInPlaylist;
+            ALOGI("We've missed the boat, restarting playback."
+                  "  mStartup=%d, was  looking for %d in %d-%d",
+                    mStartup, mSeqNumber, firstSeqNumberInPlaylist,
+                    lastSeqNumberInPlaylist);
+            mSeqNumber = lastSeqNumberInPlaylist - 3;
+            if (mSeqNumber < firstSeqNumberInPlaylist) {
+                mSeqNumber = firstSeqNumberInPlaylist;
+            }
             explicitDiscontinuity = true;
 
             // fall through
@@ -621,50 +830,160 @@ void PlaylistFetcher::onDownloadNext() {
 
     ALOGV("fetching '%s'", uri.c_str());
 
-    sp<ABuffer> buffer;
-    status_t err = mSession->fetchFile(
-            uri.c_str(), &buffer, range_offset, range_length);
-
-    if (err != OK) {
-        ALOGE("failed to fetch .ts segment at url '%s'", uri.c_str());
-        notifyError(err);
-        return;
+    sp<DataSource> source;
+    sp<ABuffer> buffer, tsBuffer;
+    // decrypt a junk buffer to prefetch key; since a session uses only one http connection,
+    // this avoids interleaved connections to the key and segment file.
+    {
+        sp<ABuffer> junk = new ABuffer(16);
+        junk->setRange(0, 16);
+        status_t err = decryptBuffer(mSeqNumber - firstSeqNumberInPlaylist, junk,
+                true /* first */);
+        if (err != OK) {
+            notifyError(err);
+            return;
+        }
     }
 
-    CHECK(buffer != NULL);
+    // block-wise download
+    ssize_t bytesRead;
+    do {
+        bytesRead = mSession->fetchFile(
+                uri.c_str(), &buffer, range_offset, range_length, kDownloadBlockSize, &source);
+
+        if (bytesRead < 0) {
+            status_t err = bytesRead;
+            ALOGE("failed to fetch .ts segment at url '%s'", uri.c_str());
+            notifyError(err);
+            return;
+        }
 
-    err = decryptBuffer(mSeqNumber - firstSeqNumberInPlaylist, buffer);
+        CHECK(buffer != NULL);
 
-    if (err != OK) {
-        ALOGE("decryptBuffer failed w/ error %d", err);
+        size_t size = buffer->size();
+        // Set decryption range.
+        buffer->setRange(size - bytesRead, bytesRead);
+        status_t err = decryptBuffer(mSeqNumber - firstSeqNumberInPlaylist, buffer,
+                buffer->offset() == 0 /* first */);
+        // Unset decryption range.
+        buffer->setRange(0, size);
 
-        notifyError(err);
-        return;
-    }
+        if (err != OK) {
+            ALOGE("decryptBuffer failed w/ error %d", err);
 
-    if (mStartup || seekDiscontinuity || explicitDiscontinuity) {
-        // Signal discontinuity.
+            notifyError(err);
+            return;
+        }
 
-        if (mPlaylist->isComplete() || mPlaylist->isEvent()) {
-            // If this was a live event this made no sense since
-            // we don't have access to all the segment before the current
-            // one.
-            mNextPTSTimeUs = getSegmentStartTimeUs(mSeqNumber);
+        if (mStartup || seekDiscontinuity || explicitDiscontinuity) {
+            // Signal discontinuity.
+
+            if (mPlaylist->isComplete() || mPlaylist->isEvent()) {
+                // If this was a live event this made no sense since
+                // we don't have access to all the segment before the current
+                // one.
+                mNextPTSTimeUs = getSegmentStartTimeUs(mSeqNumber);
+            }
+
+            if (seekDiscontinuity || explicitDiscontinuity) {
+                ALOGI("queueing discontinuity (seek=%d, explicit=%d)",
+                     seekDiscontinuity, explicitDiscontinuity);
+
+                queueDiscontinuity(
+                        explicitDiscontinuity
+                            ? ATSParser::DISCONTINUITY_FORMATCHANGE
+                            : ATSParser::DISCONTINUITY_SEEK,
+                        NULL /* extra */);
+            }
+        }
+
+        err = OK;
+        if (bufferStartsWithTsSyncByte(buffer)) {
+            // Incremental extraction is only supported for MPEG2 transport streams.
+            if (tsBuffer == NULL) {
+                tsBuffer = new ABuffer(buffer->data(), buffer->capacity());
+                tsBuffer->setRange(0, 0);
+            } else if (tsBuffer->capacity() != buffer->capacity()) {
+                size_t tsOff = tsBuffer->offset(), tsSize = tsBuffer->size();
+                tsBuffer = new ABuffer(buffer->data(), buffer->capacity());
+                tsBuffer->setRange(tsOff, tsSize);
+            }
+            tsBuffer->setRange(tsBuffer->offset(), tsBuffer->size() + bytesRead);
+
+            err = extractAndQueueAccessUnitsFromTs(tsBuffer);
+        }
+
+        if (err == -EAGAIN) {
+            // bad starting sequence number hint
+            postMonitorQueue();
+            return;
         }
 
-        if (seekDiscontinuity || explicitDiscontinuity) {
-            ALOGI("queueing discontinuity (seek=%d, explicit=%d)",
-                 seekDiscontinuity, explicitDiscontinuity);
+        if (err == ERROR_OUT_OF_RANGE) {
+            // reached stopping point
+            stopAsync(/* selfTriggered = */ true);
+            return;
+        }
 
-            queueDiscontinuity(
-                    explicitDiscontinuity
-                        ? ATSParser::DISCONTINUITY_FORMATCHANGE
-                        : ATSParser::DISCONTINUITY_SEEK,
-                    NULL /* extra */);
+        if (err != OK) {
+            notifyError(err);
+            return;
         }
+
+        mStartup = false;
+    } while (bytesRead != 0);
+
+    if (bufferStartsWithTsSyncByte(buffer)) {
+        // If we still don't see a stream after fetching a full ts segment mark it as
+        // nonexistent.
+        const size_t kNumTypes = ATSParser::NUM_SOURCE_TYPES;
+        ATSParser::SourceType srcTypes[kNumTypes] =
+                { ATSParser::VIDEO, ATSParser::AUDIO };
+        LiveSession::StreamType streamTypes[kNumTypes] =
+                { LiveSession::STREAMTYPE_VIDEO, LiveSession::STREAMTYPE_AUDIO };
+
+        for (size_t i = 0; i < kNumTypes; i++) {
+            ATSParser::SourceType srcType = srcTypes[i];
+            LiveSession::StreamType streamType = streamTypes[i];
+
+            sp<AnotherPacketSource> source =
+                static_cast<AnotherPacketSource *>(
+                    mTSParser->getSource(srcType).get());
+
+            if (source == NULL) {
+                ALOGW("MPEG2 Transport stream does not contain %s data.",
+                      srcType == ATSParser::VIDEO ? "video" : "audio");
+
+                mStreamTypeMask &= ~streamType;
+                mPacketSources.removeItem(streamType);
+            }
+        }
+
+    }
+
+    if (checkDecryptPadding(buffer) != OK) {
+        ALOGE("Incorrect padding bytes after decryption.");
+        notifyError(ERROR_MALFORMED);
+        return;
     }
 
-    err = extractAndQueueAccessUnits(buffer, itemMeta);
+    status_t err = OK;
+    if (tsBuffer != NULL) {
+        AString method;
+        CHECK(buffer->meta()->findString("cipher-method", &method));
+        if ((tsBuffer->size() > 0 && method == "NONE")
+                || tsBuffer->size() > 16) {
+            ALOGE("MPEG2 transport stream is not an even multiple of 188 "
+                    "bytes in length.");
+            notifyError(ERROR_MALFORMED);
+            return;
+        }
+    }
+
+    // bulk extract non-ts files
+    if (tsBuffer == NULL) {
+      err = extractAndQueueAccessUnits(buffer, itemMeta);
+    }
 
     if (err != OK) {
         notifyError(err);
@@ -674,8 +993,6 @@ void PlaylistFetcher::onDownloadNext() {
     ++mSeqNumber;
 
     postMonitorQueue();
-
-    mStartup = false;
 }
 
 int32_t PlaylistFetcher::getSeqNumberForTime(int64_t timeUs) const {
@@ -710,95 +1027,163 @@ int32_t PlaylistFetcher::getSeqNumberForTime(int64_t timeUs) const {
     return firstSeqNumberInPlaylist + index;
 }
 
-status_t PlaylistFetcher::extractAndQueueAccessUnits(
-        const sp<ABuffer> &buffer, const sp<AMessage> &itemMeta) {
-    if (buffer->size() > 0 && buffer->data()[0] == 0x47) {
-        // Let's assume this is an MPEG2 transport stream.
+status_t PlaylistFetcher::extractAndQueueAccessUnitsFromTs(const sp<ABuffer> &buffer) {
+    if (mTSParser == NULL) {
+        // Use TS_TIMESTAMPS_ARE_ABSOLUTE so pts carry over between fetchers.
+        mTSParser = new ATSParser(ATSParser::TS_TIMESTAMPS_ARE_ABSOLUTE);
+    }
 
-        if ((buffer->size() % 188) != 0) {
-            ALOGE("MPEG2 transport stream is not an even multiple of 188 "
-                  "bytes in length.");
-            return ERROR_MALFORMED;
-        }
+    if (mNextPTSTimeUs >= 0ll) {
+        sp<AMessage> extra = new AMessage;
+        // Since we are using absolute timestamps, signal an offset of 0 to prevent
+        // ATSParser from skewing the timestamps of access units.
+        extra->setInt64(IStreamListener::kKeyMediaTimeUs, 0);
 
-        if (mTSParser == NULL) {
-            mTSParser = new ATSParser;
-        }
+        mTSParser->signalDiscontinuity(
+                ATSParser::DISCONTINUITY_SEEK, extra);
 
-        if (mNextPTSTimeUs >= 0ll) {
-            sp<AMessage> extra = new AMessage;
-            extra->setInt64(IStreamListener::kKeyMediaTimeUs, mNextPTSTimeUs);
+        mNextPTSTimeUs = -1ll;
+    }
 
-            mTSParser->signalDiscontinuity(
-                    ATSParser::DISCONTINUITY_SEEK, extra);
+    size_t offset = 0;
+    while (offset + 188 <= buffer->size()) {
+        status_t err = mTSParser->feedTSPacket(buffer->data() + offset, 188);
 
-            mNextPTSTimeUs = -1ll;
+        if (err != OK) {
+            return err;
         }
 
-        size_t offset = 0;
-        while (offset < buffer->size()) {
-            status_t err = mTSParser->feedTSPacket(buffer->data() + offset, 188);
+        offset += 188;
+    }
+    // setRange to indicate consumed bytes.
+    buffer->setRange(buffer->offset() + offset, buffer->size() - offset);
+
+    status_t err = OK;
+    for (size_t i = mPacketSources.size(); i-- > 0;) {
+        sp<AnotherPacketSource> packetSource = mPacketSources.valueAt(i);
+
+        const char *key;
+        ATSParser::SourceType type;
+        const LiveSession::StreamType stream = mPacketSources.keyAt(i);
+        switch (stream) {
+            case LiveSession::STREAMTYPE_VIDEO:
+                type = ATSParser::VIDEO;
+                key = "timeUsVideo";
+                break;
+
+            case LiveSession::STREAMTYPE_AUDIO:
+                type = ATSParser::AUDIO;
+                key = "timeUsAudio";
+                break;
 
-            if (err != OK) {
-                return err;
+            case LiveSession::STREAMTYPE_SUBTITLES:
+            {
+                ALOGE("MPEG2 Transport streams do not contain subtitles.");
+                return ERROR_MALFORMED;
+                break;
             }
 
-            offset += 188;
+            default:
+                TRESPASS();
         }
 
-        for (size_t i = mPacketSources.size(); i-- > 0;) {
-            sp<AnotherPacketSource> packetSource = mPacketSources.valueAt(i);
+        sp<AnotherPacketSource> source =
+            static_cast<AnotherPacketSource *>(
+                    mTSParser->getSource(type).get());
 
-            ATSParser::SourceType type;
-            switch (mPacketSources.keyAt(i)) {
-                case LiveSession::STREAMTYPE_VIDEO:
-                    type = ATSParser::VIDEO;
-                    break;
+        if (source == NULL) {
+            continue;
+        }
 
-                case LiveSession::STREAMTYPE_AUDIO:
-                    type = ATSParser::AUDIO;
+        int64_t timeUs;
+        sp<ABuffer> accessUnit;
+        status_t finalResult;
+        while (source->hasBufferAvailable(&finalResult)
+                && source->dequeueAccessUnit(&accessUnit) == OK) {
+
+            CHECK(accessUnit->meta()->findInt64("timeUs", &timeUs));
+            if (mMinStartTimeUs > 0) {
+                if (timeUs < mMinStartTimeUs) {
+                    // TODO untested path
+                    // try a later ts
+                    int32_t targetDuration;
+                    mPlaylist->meta()->findInt32("target-duration", &targetDuration);
+                    int32_t incr = (mMinStartTimeUs - timeUs) / 1000000 / targetDuration;
+                    if (incr == 0) {
+                        // increment mSeqNumber by at least one
+                        incr = 1;
+                    }
+                    mSeqNumber += incr;
+                    err = -EAGAIN;
                     break;
+                } else {
+                    int64_t startTimeUs;
+                    if (mStartTimeUsNotify != NULL
+                            && !mStartTimeUsNotify->findInt64(key, &startTimeUs)) {
+                        mStartTimeUsNotify->setInt64(key, timeUs);
+
+                        uint32_t streamMask = 0;
+                        mStartTimeUsNotify->findInt32("streamMask", (int32_t *) &streamMask);
+                        streamMask |= mPacketSources.keyAt(i);
+                        mStartTimeUsNotify->setInt32("streamMask", streamMask);
+
+                        if (streamMask == mStreamTypeMask) {
+                            mStartTimeUsNotify->post();
+                            mStartTimeUsNotify.clear();
+                        }
+                    }
+                }
+            }
 
-                case LiveSession::STREAMTYPE_SUBTITLES:
-                {
-                    ALOGE("MPEG2 Transport streams do not contain subtitles.");
-                    return ERROR_MALFORMED;
+            if (mStopParams != NULL) {
+                // Queue discontinuity in original stream.
+                int64_t stopTimeUs;
+                if (!mStopParams->findInt64(key, &stopTimeUs) || timeUs >= stopTimeUs) {
+                    packetSource->queueAccessUnit(mSession->createFormatChangeBuffer());
+                    mStreamTypeMask &= ~stream;
+                    mPacketSources.removeItemsAt(i);
                     break;
                 }
-
-                default:
-                    TRESPASS();
             }
 
-            sp<AnotherPacketSource> source =
-                static_cast<AnotherPacketSource *>(
-                        mTSParser->getSource(type).get());
-
-            if (source == NULL) {
-                ALOGW("MPEG2 Transport stream does not contain %s data.",
-                      type == ATSParser::VIDEO ? "video" : "audio");
+            // Note that we do NOT dequeue any discontinuities except for format change.
 
-                mStreamTypeMask &= ~mPacketSources.keyAt(i);
-                mPacketSources.removeItemsAt(i);
-                continue;
+            // for simplicity, store a reference to the format in each unit
+            sp<MetaData> format = source->getFormat();
+            if (format != NULL) {
+                accessUnit->meta()->setObject("format", format);
             }
 
-            sp<ABuffer> accessUnit;
-            status_t finalResult;
-            while (source->hasBufferAvailable(&finalResult)
-                    && source->dequeueAccessUnit(&accessUnit) == OK) {
-                // Note that we do NOT dequeue any discontinuities.
+            // Stash the sequence number so we can hint future playlist where to start at.
+            accessUnit->meta()->setInt32("seq", mSeqNumber);
+            packetSource->queueAccessUnit(accessUnit);
+        }
 
-                packetSource->queueAccessUnit(accessUnit);
-            }
+        if (err != OK) {
+            break;
+        }
+    }
 
-            if (packetSource->getFormat() == NULL) {
-                packetSource->setFormat(source->getFormat());
-            }
+    if (err != OK) {
+        for (size_t i = mPacketSources.size(); i-- > 0;) {
+            sp<AnotherPacketSource> packetSource = mPacketSources.valueAt(i);
+            packetSource->clear();
         }
+        return err;
+    }
 
-        return OK;
-    } else if (buffer->size() >= 7 && !memcmp("WEBVTT\n", buffer->data(), 7)) {
+    if (!mStreamTypeMask) {
+        // Signal gap is filled between original and new stream.
+        ALOGV("ERROR OUT OF RANGE");
+        return ERROR_OUT_OF_RANGE;
+    }
+
+    return OK;
+}
+
+status_t PlaylistFetcher::extractAndQueueAccessUnits(
+        const sp<ABuffer> &buffer, const sp<AMessage> &itemMeta) {
+    if (buffer->size() >= 7 && !memcmp("WEBVTT\n", buffer->data(), 7)) {
         if (mStreamTypeMask != LiveSession::STREAMTYPE_SUBTITLES) {
             ALOGE("This stream only contains subtitles.");
             return ERROR_MALFORMED;
@@ -811,6 +1196,7 @@ status_t PlaylistFetcher::extractAndQueueAccessUnits(
         CHECK(itemMeta->findInt64("durationUs", &durationUs));
         buffer->meta()->setInt64("timeUs", getSegmentStartTimeUs(mSeqNumber));
         buffer->meta()->setInt64("durationUs", durationUs);
+        buffer->meta()->setInt32("seq", mSeqNumber);
 
         packetSource->queueAccessUnit(buffer);
         return OK;
@@ -936,6 +1322,18 @@ status_t PlaylistFetcher::extractAndQueueAccessUnits(
             | (adtsHeader[4] << 3)
             | (adtsHeader[5] >> 5);
 
+        if (aac_frame_length == 0) {
+            const uint8_t *id3Header = adtsHeader;
+            if (!memcmp(id3Header, "ID3", 3)) {
+                ID3 id3(id3Header, buffer->size() - offset, true);
+                if (id3.isValid()) {
+                    offset += id3.rawSize();
+                    continue;
+                };
+            }
+            return ERROR_MALFORMED;
+        }
+
         CHECK_LE(offset + aac_frame_length, buffer->size());
 
         sp<ABuffer> unit = new ABuffer(aac_frame_length);
@@ -947,6 +1345,7 @@ status_t PlaylistFetcher::extractAndQueueAccessUnits(
         // Each AAC frame encodes 1024 samples.
         numSamples += 1024;
 
+        unit->meta()->setInt32("seq", mSeqNumber);
         packetSource->queueAccessUnit(unit);
 
         offset += aac_frame_length;
@@ -974,4 +1373,33 @@ void PlaylistFetcher::updateDuration() {
     msg->post();
 }
 
+int64_t PlaylistFetcher::resumeThreshold(const sp<AMessage> &msg) {
+    int64_t durationUs, threshold;
+    if (msg->findInt64("durationUs", &durationUs)) {
+        return kNumSkipFrames * durationUs;
+    }
+
+    sp<RefBase> obj;
+    msg->findObject("format", &obj);
+    MetaData *format = static_cast<MetaData *>(obj.get());
+
+    const char *mime;
+    CHECK(format->findCString(kKeyMIMEType, &mime));
+    bool audio = !strncasecmp(mime, "audio/", 6);
+    if (audio) {
+        // Assumes 1000 samples per frame.
+        int32_t sampleRate;
+        CHECK(format->findInt32(kKeySampleRate, &sampleRate));
+        return kNumSkipFrames  /* frames */ * 1000 /* samples */
+                * (1000000 / sampleRate) /* sample duration (us) */;
+    } else {
+        int32_t frameRate;
+        if (format->findInt32(kKeyFrameRate, &frameRate) && frameRate > 0) {
+            return kNumSkipFrames * (1000000 / frameRate);
+        }
+    }
+
+    return 500000ll;
+}
+
 }  // namespace android
diff --git a/media/libstagefright/httplive/PlaylistFetcher.h b/media/libstagefright/httplive/PlaylistFetcher.h
index 1648e02..7e21523 100644
--- a/media/libstagefright/httplive/PlaylistFetcher.h
+++ b/media/libstagefright/httplive/PlaylistFetcher.h
@@ -43,6 +43,7 @@ struct PlaylistFetcher : public AHandler {
         kWhatTemporarilyDoneFetching,
         kWhatPrepared,
         kWhatPreparationFailed,
+        kWhatStartedAt,
     };
 
     PlaylistFetcher(
@@ -56,11 +57,15 @@ struct PlaylistFetcher : public AHandler {
             const sp<AnotherPacketSource> &audioSource,
             const sp<AnotherPacketSource> &videoSource,
             const sp<AnotherPacketSource> &subtitleSource,
-            int64_t startTimeUs = -1ll);
+            int64_t startTimeUs = -1ll,
+            int64_t minStartTimeUs = 0ll /* start after this timestamp */,
+            int32_t startSeqNumberHint = -1 /* try starting at this sequence number */);
 
     void pauseAsync();
 
-    void stopAsync();
+    void stopAsync(bool selfTriggered = false);
+
+    void resumeUntilAsync(const sp<AMessage> &params);
 
 protected:
     virtual ~PlaylistFetcher();
@@ -76,16 +81,28 @@ private:
         kWhatPause          = 'paus',
         kWhatStop           = 'stop',
         kWhatMonitorQueue   = 'moni',
+        kWhatResumeUntil    = 'rsme',
+        kWhatDownloadNext   = 'dlnx',
     };
 
     static const int64_t kMinBufferedDurationUs;
+    static const int64_t kMaxMonitorDelayUs;
+    static const int32_t kDownloadBlockSize;
+    static const int32_t kNumSkipFrames;
+
+    static bool bufferStartsWithTsSyncByte(const sp<ABuffer>& buffer);
 
+    // notifications to mSession
     sp<AMessage> mNotify;
+    sp<AMessage> mStartTimeUsNotify;
+
     sp<LiveSession> mSession;
     AString mURI;
 
     uint32_t mStreamTypeMask;
     int64_t mStartTimeUs;
+    int64_t mMinStartTimeUs; // start fetching no earlier than this value
+    sp<AMessage> mStopParams; // message containing the latest timestamps we should fetch.
 
     KeyedVector<LiveSession::StreamType, sp<AnotherPacketSource> >
         mPacketSources;
@@ -97,6 +114,7 @@ private:
     int32_t mSeqNumber;
     int32_t mNumRetries;
     bool mStartup;
+    bool mPrepared;
     int64_t mNextPTSTimeUs;
 
     int32_t mMonitorQueueGeneration;
@@ -117,13 +135,29 @@ private:
     uint64_t mFirstPTS;
     int64_t mAbsoluteTimeAnchorUs;
 
+    // Stores the initialization vector to decrypt the next block of cipher text, which can
+    // either be derived from the sequence number, read from the manifest, or copied from
+    // the last block of cipher text (cipher-block chaining).
+    unsigned char mAESInitVec[16];
+
+    // Set first to true if decrypting the first segment of a playlist segment. When
+    // first is true, reset the initialization vector based on the available
+    // information in the manifest; otherwise, use the initialization vector as
+    // updated by the last call to AES_cbc_encrypt.
+    //
+    // For the input to decrypt correctly, decryptBuffer must be called on
+    // consecutive byte ranges on block boundaries, e.g. 0..15, 16..47, 48..63,
+    // and so on.
     status_t decryptBuffer(
-            size_t playlistIndex, const sp<ABuffer> &buffer);
+            size_t playlistIndex, const sp<ABuffer> &buffer,
+            bool first = true);
+    status_t checkDecryptPadding(const sp<ABuffer> &buffer);
 
-    void postMonitorQueue(int64_t delayUs = 0);
+    void postMonitorQueue(int64_t delayUs = 0, int64_t minDelayUs = 0);
     void cancelMonitorQueue();
 
-    bool timeToRefreshPlaylist(int64_t nowUs) const;
+    int64_t delayUsToRefreshPlaylist() const;
+    status_t refreshPlaylist();
 
     // Returns the media time in us of the segment specified by seqNumber.
     // This is computed by summing the durations of all segments before it.
@@ -131,10 +165,15 @@ private:
 
     status_t onStart(const sp<AMessage> &msg);
     void onPause();
-    void onStop();
+    void onStop(const sp<AMessage> &msg);
     void onMonitorQueue();
     void onDownloadNext();
 
+    // Resume a fetcher to continue until the stopping point stored in msg.
+    status_t onResumeUntil(const sp<AMessage> &msg);
+
+    status_t extractAndQueueAccessUnitsFromTs(const sp<ABuffer> &buffer);
+
     status_t extractAndQueueAccessUnits(
             const sp<ABuffer> &buffer, const sp<AMessage> &itemMeta);
 
@@ -147,6 +186,10 @@ private:
 
     void updateDuration();
 
+    // Before resuming a fetcher in onResume, check the remaining duration is longer than that
+    // returned by resumeThreshold.
+    int64_t resumeThreshold(const sp<AMessage> &msg);
+
     DISALLOW_EVIL_CONSTRUCTORS(PlaylistFetcher);
 };