在
Android 4.4.2中,我使用MediaCodec解码mp3文件.
我使用queueInputBuffer()来排队输入mp3编码的帧和dequeueOutputBuffer()来获得解码的帧.
但是解码器从第8帧开始(基于bufferInfo.presentationTimeUs)提供解码输出,并跳过初始7帧.这种情况只发生在几个流中,但不适用于所有流.此外,这种行为在许多运行中是一致的.
我使用queueInputBuffer()来排队输入mp3编码的帧和dequeueOutputBuffer()来获得解码的帧.
但是解码器从第8帧开始(基于bufferInfo.presentationTimeUs)提供解码输出,并跳过初始7帧.这种情况只发生在几个流中,但不适用于所有流.此外,这种行为在许多运行中是一致的.
我想要所有帧的解码输出,我不想跳过任何帧.任何人都可以帮助我了解为什么框架被跳过？我保证流不会被破坏.因为我收到INFO_TRY_AGAIN到第7帧,当有效的缓冲区索引被’dequeueOutputBuffer’返回时,它的呈现时间总是第8帧.
以下是排队码：
Log.e(TAG,"audptOffset = "+audptOffset+"input PT = "+audpt);
audcodec.queueInputBuffer(audInbufIndex,audchunkSize,audpt,0);
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
解决方法
MPEG-1 Layer III(MP3)具有从属帧,您不能从任何像Layer I或Layer II这样的帧开始.从提供的
link引用,“在最坏的情况下,可能需要9个输入帧才能解码一个单一的帧.这很可能是你看到的.尽管前7帧中的每一帧都具有与之相关联的PTS,但直到到达第8帧,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.您需要手动解析所讨论的流的字节,才能完全验证这是发生了什么,但我怀疑您实际上是在播放所有的帧.
