Bug 1082545 - Make fastSeek always fast. r=sotaro

--HG--
extra : rebase_source : 4e12b971b2ee18931a54d30d51fc71437e095cdd

dom/media/omx/OmxDecoder.cpp

@@ -33,6 +33,10 @@
 #include "OMXCodecProxy.h"
 #include "OmxDecoder.h"
 
+#define LOG_TAG "OmxDecoder"
+#include <android/log.h>
+#define ALOG(...) __android_log_print(ANDROID_LOG_DEBUG, LOG_TAG, __VA_ARGS__)
+
 #ifdef PR_LOGGING
 PRLogModuleInfo *gOmxDecoderLog;
 #define LOG(type, msg...) PR_LOG(gOmxDecoderLog, type, (msg))
@@ -66,7 +70,8 @@ OmxDecoder::OmxDecoder(MediaResource *aResource,
   mIsVideoSeeking(false),
   mAudioMetadataRead(false),
   mAudioPaused(false),
-  mVideoPaused(false)
+  mVideoPaused(false),
+  mVideoLastFrameTime(-1)
 {
   mLooper = new ALooper;
   mLooper->setName("OmxDecoder");
@@ -556,14 +561,43 @@ bool OmxDecoder::ReadVideo(VideoFrame *aFrame, int64_t aTimeUs,
       mIsVideoSeeking = true;
     }
     MediaSource::ReadOptions options;
-    options.setSeekTo(aTimeUs, MediaSource::ReadOptions::SEEK_PREVIOUS_SYNC);
-    err = mVideoSource->read(&mVideoBuffer, &options);
-    {
-      Mutex::Autolock autoLock(mSeekLock);
-      mIsVideoSeeking = false;
-      PostReleaseVideoBuffer(nullptr, FenceHandle());
+    MediaSource::ReadOptions::SeekMode seekMode;
+    // If the last timestamp of decoded frame is smaller than seekTime,
+    // seek to next key frame. Otherwise seek to the previos one.
+    if (mVideoLastFrameTime > aTimeUs || mVideoLastFrameTime == -1) {
+      seekMode = MediaSource::ReadOptions::SEEK_PREVIOUS_SYNC;
+    } else {
+      seekMode = MediaSource::ReadOptions::SEEK_NEXT_SYNC;
     }
 
+    bool findNextBuffer = true;
+    while (findNextBuffer) {
+      options.setSeekTo(aTimeUs, seekMode);
+      findNextBuffer = false;
+      err = mVideoSource->read(&mVideoBuffer, &options);
+      {
+        Mutex::Autolock autoLock(mSeekLock);
+        mIsVideoSeeking = false;
+        PostReleaseVideoBuffer(nullptr, FenceHandle());
+      }
+      // If there is no next Keyframe, jump to the previous key frame.
+      if (err == ERROR_END_OF_STREAM && seekMode == MediaSource::ReadOptions::SEEK_NEXT_SYNC) {
+         seekMode = MediaSource::ReadOptions::SEEK_PREVIOUS_SYNC;
+	 findNextBuffer = true;
+	 {
+	   Mutex::Autolock autoLock(mSeekLock);
+	   mIsVideoSeeking = true;
+	 }
+	 continue;
+      } else if (err != OK) {
+	ALOG("Unexpected error when seeking to %lld", aTimeUs);
+        break;
+      }
+      if (mVideoBuffer->range_length() == 0) {
+        ReleaseVideoBuffer();
+	findNextBuffer = true;
+      }
+    }
     aDoSeek = false;
   } else {
     err = mVideoSource->read(&mVideoBuffer);
@@ -635,6 +669,7 @@ bool OmxDecoder::ReadVideo(VideoFrame *aFrame, int64_t aTimeUs,
     if ((aKeyframeSkip && timeUs < aTimeUs) || length == 0) {
       aFrame->mShouldSkip = true;
     }
+    mVideoLastFrameTime = timeUs;
   }
   else if (err == INFO_FORMAT_CHANGED) {
     // If the format changed, update our cached info.

dom/media/omx/OmxDecoder.h

@@ -60,6 +60,8 @@ class OmxDecoder : public OMXCodecProxy::EventListener {
   int32_t mAudioChannels;
   int32_t mAudioSampleRate;
   int64_t mDurationUs;
+  int64_t mVideoLastFrameTime;
+
   VideoFrame mVideoFrame;
   AudioFrame mAudioFrame;
   MP3FrameParser mMP3FrameParser;