Android MediaCodec不解码所有输入缓冲区

在Android 4.4.2中,我使用MediaCodec来解码mp3文件。 我正在使用queueInputBuffer()对输入的mp3编码帧进行排队,并使用dequeueOutputBuffer()来获取已解码的帧。 但解码器从第8帧开始提供解码输出(基于bufferInfo.presentationTimeUs )并跳过最初的7帧。 此方案仅针对少数流而不针对所有流发生。 此外,这种行为在许多运行中都是一致的。

我想要所有帧的解码输出,我不希望任何帧被跳过。 任何人都可以帮我理解为什么跳过帧? 我保证流不会被破坏。 因为我得到INFO_TRY_AGAIN直到第7帧,当`dequeueOutputBuffer’返回有效的缓冲区索引时,它的呈现时间总是第8帧。

以下是排队代码:

 Log.e(TAG, "audptOffset = "+audptOffset+"input PT = "+audpt); audcodec.queueInputBuffer(audInbufIndex, 0, audchunkSize, audpt, 0); 

以下是我如何调用dequeue并写入AudioTrack:

 if(!audoutputDone ){ if(!waitForAudioRelease){ auoutBufIndex = audcodec.dequeueOutputBuffer(auinfo, 100); Log.e(TAG, "Output PT = " + auinfo.presentationTimeUs+"auoutBufIndex = "+auoutBufIndex); } if (auoutBufIndex >= 0) { waitForAudioRelease = true; } else if (auoutBufIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) { auddecOutBufArray = audcodec.getOutputBuffers(); } else if (auoutBufIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) { MediaFormat newFormat = audcodec.getOutputFormat(); int sampleRate1 = newFormat.getInteger(MediaFormat.KEY_SAMPLE_RATE); int channelCount1 =newFormat.getInteger(MediaFormat.KEY_CHANNEL_COUNT); Log.e(TAG, "INFO_OUTPUT_FORMAT_CHANGED"); int minBufSize1 = AudioTrack.getMinBufferSize(sampleRate1, (channelCount1==2)? AudioFormat.CHANNEL_OUT_STEREO:AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT); audioTrack = new AudioTrack(AudioManager.STREAM_MUSIC, sampleRate1, (channelCount1==2)?AudioFormat.CHANNEL_OUT_STEREO:AudioFormat.CHANNEL_OUT_MONO, AudioFormat.ENCODING_PCM_16BIT, minBufSize1, AudioTrack.MODE_STREAM); audioTrack.play(); waitForAudioRelease = false; } audionowUs = System.currentTimeMillis(); if (auoutBufIndex >= 0) { auwhenRealUs = (auinfo.presentationTimeUs/1000) + mStartTimeRealMs - (audptOffset/1000); aulateByUs = audionowUs - auwhenRealUs; if(!audioWaitTillStartTime){ while((mStartTimeRealMs+((auinfo.presentationTimeUs/1000) - (audptOffset/1000))) >= audionowUs){ try { Thread.sleep(10); } catch (InterruptedException e) { // TODO Auto-generated catch block e.printStackTrace(); } audionowUs = System.currentTimeMillis(); } Log.e(TAG,"Play is going to start PT Difference = "+((auinfo.presentationTimeUs/1000) - (audptOffset/1000))); } 

添加更多日志:

 02-22 17:46:03.164: E/CL(28650): received play command from server 02-22 17:46:03.209: E/RealTimeClient(28650): created decoder for audio/mpeg 02-22 17:46:03.234: E/Music(28650): Output PT = 0 02-22 17:46:03.234: E/Music(28650): pt of first frame received 1215000 02-22 17:46:03.234: E/Music(28650): Input PT = 1215000 02-22 17:46:03.234: E/Music(28650): Output PT = 0 02-22 17:46:03.234: E/Music(28650): Input PT = 1241122 02-22 17:46:03.239: E/Music(28650): Output PT = 0 02-22 17:46:03.239: E/Music(28650): Input PT = 1267244 02-22 17:46:03.239: E/Music(28650): Output PT = 0 02-22 17:46:03.239: E/Music(28650): Input PT = 1293367 02-22 17:46:03.239: E/Music(28650): Output PT = 0 02-22 17:46:03.239: E/Music(28650): Input PT = 1319489 02-22 17:46:03.239: E/Music(28650): Output PT = 0 02-22 17:46:03.244: E/Music(28650): INFO_OUTPUT_FORMAT_CHANGED 02-22 17:46:03.249: I/Reverb(28650): getpid() 28650, IPCThreadState::self()->getCallingPid() 28650 02-22 17:46:03.249: E/Reverb(28650): Reverb::StartElementHandler, wrong element or attributes: boolean 02-22 17:46:03.249: E/Music(28650): Input PT = 1345612 02-22 17:46:03.254: E/Music(28650): Output PT = 1293367 02-22 17:46:03.259: E/Music(28650): Input PT = 1371734 02-22 17:46:03.259: E/Music(28650): Input PT = 1397857 02-22 17:46:03.259: E/Music(28650): Input PT = 1423979 02-22 17:46:03.259: E/Music(28650): Input PT = 1450102 02-22 17:46:03.264: E/Music(28650): Input PT = 1476224 02-22 17:46:03.269: E/Music(28650): Input PT = 1502346 02-22 17:46:03.269: E/Music(28650): Input PT = 1528469 02-22 17:46:03.269: E/Music(28650): Input PT = 1554591 02-22 17:46:03.269: E/Music(28650): Input PT = 1580714 02-22 17:46:03.269: E/Music(28650): Input PT = 1606836 02-22 17:46:03.269: E/Music(28650): Input PT = 1632959 02-22 17:46:03.269: E/Music(28650): Input PT = 1659081 02-22 17:46:04.124: W/AudioTrack(28650): releaseBuffer() track 0x5e2faf28 name=0x3 disabled, restarting 02-22 17:46:04.129: E/Music(28650): Output PT = 1319489 02-22 17:46:04.129: E/Music(28650): Input PT = 1685204 02-22 17:46:04.159: E/Music(28650): Output PT = 1345612 

MPEG-1 Layer III(MP3)具有相关帧,您不能只从第一层或第二层开始。 从提供的链接引用“在最坏的情况下,在能够解码一个帧之前可能需要9个输入帧。” 这很可能是你所看到的。 虽然前7帧中的每一帧都有一个与之相关的PTS,但直到你到达第8帧时,解码器实际上才能完全解码帧并开始播放。 播放从第8帧PTS开始。 您需要手动解析有问题的流的字节以完全validation这是发生了什么,但我怀疑您实际上正在播放所有帧。