Properly identify how much metadata we need to cache in order to instantiate

the extractor without blocking (and therefore be able to abort).

Change-Id: Id2acdde897e02baaeabadae70b7c95b66c9041b3
related-to-bug: 5666532

3 files changed, 136 insertions, 41 deletions

diff --git a/media/libstagefright/AwesomePlayer.cpp b/media/libstagefright/AwesomePlayer.cpp
index f6d054d..18dd8ef 100644
--- a/media/libstagefright/AwesomePlayer.cpp
+++ b/media/libstagefright/AwesomePlayer.cpp
@@ -1949,6 +1949,8 @@ status_t AwesomePlayer::finishSetDataSource_l() {
         mUri = newURI;
     }
 
+    AString sniffedMIME;
+
     if (!strncasecmp("http://", mUri.string(), 7)
             || !strncasecmp("https://", mUri.string(), 8)
             || isWidevineStreaming) {
@@ -1998,7 +2000,6 @@ status_t AwesomePlayer::finishSetDataSource_l() {
 
         mConnectingDataSource.clear();
 
-
         String8 contentType = dataSource->getMIMEType();
 
         if (strncasecmp(contentType.string(), "audio/", 6)) {
@@ -2020,16 +2021,51 @@ status_t AwesomePlayer::finishSetDataSource_l() {
 
                 mLock.unlock();
 
+                // Initially make sure we have at least 128 bytes for the sniff
+                // to complete without blocking.
+                static const size_t kMinBytesForSniffing = 128;
+
+                off64_t metaDataSize = -1ll;
                 for (;;) {
                     status_t finalStatus;
                     size_t cachedDataRemaining =
                         mCachedSource->approxDataRemaining(&finalStatus);
 
-                    if (finalStatus != OK || cachedDataRemaining >= kHighWaterMarkBytes
+                    if (finalStatus != OK
+                            || (metaDataSize >= 0
+                                && cachedDataRemaining >= metaDataSize)
                             || (mFlags & PREPARE_CANCELLED)) {
                         break;
                     }
 
+                    LOGV("now cached %d bytes of data", cachedDataRemaining);
+
+                    if (metaDataSize < 0
+                            && cachedDataRemaining >= kMinBytesForSniffing) {
+                        String8 tmp;
+                        float confidence;
+                        sp<AMessage> meta;
+                        if (!dataSource->sniff(&tmp, &confidence, &meta)) {
+                            mLock.lock();
+                            return UNKNOWN_ERROR;
+                        }
+
+                        // We successfully identified the file's extractor to
+                        // be, remember this mime type so we don't have to
+                        // sniff it again when we call MediaExtractor::Create()
+                        // below.
+                        sniffedMIME = tmp.string();
+
+                        if (meta == NULL
+                                || !meta->findInt64(
+                                    "meta-data-size", &metaDataSize)) {
+                            metaDataSize = kHighWaterMarkBytes;
+                        }
+
+                        CHECK_GE(metaDataSize, 0ll);
+                        LOGV("metaDataSize = %lld bytes", metaDataSize);
+                    }
+
                     usleep(200000);
                 }
 
@@ -2067,7 +2103,8 @@ status_t AwesomePlayer::finishSetDataSource_l() {
         mWVMExtractor->setAdaptiveStreamingMode(true);
         extractor = mWVMExtractor;
     } else {
-        extractor = MediaExtractor::Create(dataSource);
+        extractor = MediaExtractor::Create(
+                dataSource, sniffedMIME.empty() ? NULL : sniffedMIME.c_str());
 
         if (extractor == NULL) {
             return UNKNOWN_ERROR;
diff --git a/media/libstagefright/MPEG4Extractor.cpp b/media/libstagefright/MPEG4Extractor.cpp
index 1ebf0a8..f6b06c7 100644
--- a/media/libstagefright/MPEG4Extractor.cpp
+++ b/media/libstagefright/MPEG4Extractor.cpp
@@ -30,6 +30,7 @@
 #include <string.h>
 
 #include <media/stagefright/foundation/ADebug.h>
+#include <media/stagefright/foundation/AMessage.h>
 #include <media/stagefright/DataSource.h>
 #include <media/stagefright/MediaBuffer.h>
 #include <media/stagefright/MediaBufferGroup.h>
@@ -2301,51 +2302,121 @@ static bool isCompatibleBrand(uint32_t fourcc) {
 
 // Attempt to actually parse the 'ftyp' atom and determine if a suitable
 // compatible brand is present.
+// Also try to identify where this file's metadata ends
+// (end of the 'moov' atom) and report it to the caller as part of
+// the metadata.
 static bool BetterSniffMPEG4(
-        const sp<DataSource> &source, String8 *mimeType, float *confidence) {
-    uint8_t header[12];
-    if (source->readAt(0, header, 12) != 12
-            || memcmp("ftyp", &header[4], 4)) {
-        return false;
-    }
+        const sp<DataSource> &source, String8 *mimeType, float *confidence,
+        sp<AMessage> *meta) {
+    // We scan up to 128 bytes to identify this file as an MP4.
+    static const off64_t kMaxScanOffset = 128ll;
 
-    size_t atomSize = U32_AT(&header[0]);
-    if (atomSize < 16 || (atomSize % 4) != 0) {
-        return false;
-    }
+    off64_t offset = 0ll;
+    bool foundGoodFileType = false;
+    off64_t moovAtomEndOffset = -1ll;
+    bool done = false;
 
-    bool success = false;
-    if (isCompatibleBrand(U32_AT(&header[8]))) {
-        success = true;
-    } else {
-        size_t numCompatibleBrands = (atomSize - 16) / 4;
-        for (size_t i = 0; i < numCompatibleBrands; ++i) {
-            uint8_t tmp[4];
-            if (source->readAt(16 + i * 4, tmp, 4) != 4) {
+    while (!done && offset < kMaxScanOffset) {
+        uint32_t hdr[2];
+        if (source->readAt(offset, hdr, 8) < 8) {
+            return false;
+        }
+
+        uint64_t chunkSize = ntohl(hdr[0]);
+        uint32_t chunkType = ntohl(hdr[1]);
+        off64_t chunkDataOffset = offset + 8;
+
+        if (chunkSize == 1) {
+            if (source->readAt(offset + 8, &chunkSize, 8) < 8) {
                 return false;
             }
 
-            if (isCompatibleBrand(U32_AT(&tmp[0]))) {
-                success = true;
+            chunkSize = ntoh64(chunkSize);
+            chunkDataOffset += 8;
+
+            if (chunkSize < 16) {
+                // The smallest valid chunk is 16 bytes long in this case.
+                return false;
+            }
+        } else if (chunkSize < 8) {
+            // The smallest valid chunk is 8 bytes long.
+            return false;
+        }
+
+        off64_t chunkDataSize = offset + chunkSize - chunkDataOffset;
+
+        switch (chunkType) {
+            case FOURCC('f', 't', 'y', 'p'):
+            {
+                if (chunkDataSize < 8) {
+                    return false;
+                }
+
+                uint32_t numCompatibleBrands = (chunkDataSize - 8) / 4;
+                for (size_t i = 0; i < numCompatibleBrands + 2; ++i) {
+                    if (i == 1) {
+                        // Skip this index, it refers to the minorVersion,
+                        // not a brand.
+                        continue;
+                    }
+
+                    uint32_t brand;
+                    if (source->readAt(
+                                chunkDataOffset + 4 * i, &brand, 4) < 4) {
+                        return false;
+                    }
+
+                    brand = ntohl(brand);
+
+                    if (isCompatibleBrand(brand)) {
+                        foundGoodFileType = true;
+                        break;
+                    }
+                }
+
+                if (!foundGoodFileType) {
+                    return false;
+                }
+
                 break;
             }
+
+            case FOURCC('m', 'o', 'o', 'v'):
+            {
+                moovAtomEndOffset = offset + chunkSize;
+
+                done = true;
+                break;
+            }
+
+            default:
+                break;
         }
+
+        offset += chunkSize;
     }
 
-    if (!success) {
+    if (!foundGoodFileType) {
         return false;
     }
 
     *mimeType = MEDIA_MIMETYPE_CONTAINER_MPEG4;
     *confidence = 0.4f;
 
+    if (moovAtomEndOffset >= 0) {
+        *meta = new AMessage;
+        (*meta)->setInt64("meta-data-size", moovAtomEndOffset);
+
+        LOGV("found metadata size: %lld", moovAtomEndOffset);
+    }
+
     return true;
 }
 
 bool SniffMPEG4(
         const sp<DataSource> &source, String8 *mimeType, float *confidence,
-        sp<AMessage> *) {
-    if (BetterSniffMPEG4(source, mimeType, confidence)) {
+        sp<AMessage> *meta) {
+    if (BetterSniffMPEG4(source, mimeType, confidence, meta)) {
         return true;
     }
 
diff --git a/media/libstagefright/SampleTable.cpp b/media/libstagefright/SampleTable.cpp
index ebad321..69d1785 100644
--- a/media/libstagefright/SampleTable.cpp
+++ b/media/libstagefright/SampleTable.cpp
@@ -631,14 +631,7 @@ status_t SampleTable::findSyncSampleNear(
         --left;
     }
 
-    uint32_t x;
-    if (mDataSource->readAt(
-                mSyncSampleOffset + 8 + left * 4, &x, 4) != 4) {
-        return ERROR_IO;
-    }
-
-    x = ntohl(x);
-    --x;
+    uint32_t x = mSyncSamples[left];
 
     if (left + 1 < mNumSyncSamples) {
         uint32_t y = mSyncSamples[left + 1];
@@ -679,13 +672,7 @@ status_t SampleTable::findSyncSampleNear(
             if (x > start_sample_index) {
                 CHECK(left > 0);
 
-                if (mDataSource->readAt(
-                            mSyncSampleOffset + 8 + (left - 1) * 4, &x, 4) != 4) {
-                    return ERROR_IO;
-                }
-
-                x = ntohl(x);
-                --x;
+                x = mSyncSamples[left - 1];
 
                 CHECK(x <= start_sample_index);
             }