Initial HLS seamless switch implementation.

Bug: 11854054
Change-Id: I75fc2a258111295039ac13cc37e407df25891dd2

1 files changed, 36 insertions, 0 deletions

diff --git a/media/libstagefright/httplive/LiveSession.h b/media/libstagefright/httplive/LiveSession.h
index c4d125c..91bbcea 100644
--- a/media/libstagefright/httplive/LiveSession.h
+++ b/media/libstagefright/httplive/LiveSession.h
@@ -83,6 +83,11 @@ 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();
 
@@ -101,6 +106,7 @@ private:
         kWhatChangeConfiguration2       = 'chC2',
         kWhatChangeConfiguration3       = 'chC3',
         kWhatFinishDisconnect2          = 'fin2',
+        kWhatSwapped                    = 'swap',
     };
 
     struct BandwidthItem {
@@ -112,6 +118,7 @@ private:
         sp<PlaylistFetcher> mFetcher;
         int64_t mDurationUs;
         bool mIsPrepared;
+        bool mToBeRemoved;
     };
 
     struct StreamItem {
@@ -146,9 +153,26 @@ private:
     KeyedVector<AString, FetcherInfo> mFetcherInfos;
     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;
@@ -157,6 +181,7 @@ private:
     int64_t mRealTimeBaseUs;
 
     bool mReconfigurationInProgress;
+    bool mSwitchInProgress;
     uint32_t mDisconnectReplyID;
 
     sp<PlaylistFetcher> addFetcher(const char *uri);
@@ -199,16 +224,27 @@ private:
     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);
 };