我正在使用MediaCodec API将视频和音频编码为mp4文件。数据在不同的线程中编码。有时在某些设备上，音频编码器停止返回任何可用的输入缓冲区，因此MediaMuxer在尝试停止时会崩溃。这是我的代码：
配置媒体编解码器：
public static final String MIME_TYPE_AUDIO = "audio/mp4a-latm";
public static final int SAMPLE_RATE = 44100;
public static final int CHANNEL_COUNT = 1;
public static final int CHANNEL_CONFIG = AudioFormat.CHANNEL_IN_MONO;
public static final int BIT_RATE_AUDIO = 128000;
public static final int SAMPLES_PER_FRAME = 1024 * 2;
public static final int FRAMES_PER_BUFFER = 24;
public static final int AUDIO_FORMAT = AudioFormat.ENCODING_PCM_16BIT;
public static final int AUDIO_SOURCE = MediaRecorder.AudioSource.MIC;
public static final int MAX_INPUT_SIZE = 16384 * 4;
public static final int MAX_SAMPLE_SIZE = 256 * 1024;
private AudioRecord audioRecord;
private ByteBuffer[] inputBuffers;
private ByteBuffer inputBuffer;
private MediaExtractor mediaExtractor;
private boolean audioSended = false;
private boolean completed = false;
private int sampleCount;
private int iBufferSize;
public AudioEncoderCore(MovieMuxer muxer) throws IOException {
this.muxer = muxer;
bufferInfo = new MediaCodec.BufferInfo();
MediaFormat mediaFormat = null;
mediaFormat = MediaFormat.createAudioFormat(MIME_TYPE_AUDIO, SAMPLE_RATE, CHANNEL_COUNT);
mediaFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, MediaCodecInfo.CodecProfileLevel.AACObjectLC);
mediaFormat.setInteger(MediaFormat.KEY_MAX_INPUT_SIZE, MAX_INPUT_SIZE);
mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, BIT_RATE_AUDIO);
encoder = MediaCodec.createEncoderByType(MIME_TYPE_AUDIO);
encoder.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
encoder.start();
iBufferSize = SAMPLES_PER_FRAME * FRAMES_PER_BUFFER;
// Ensure buffer is adequately sized for the AudioRecord
// object to initialize
int iMinBufferSize = AudioRecord.getMinBufferSize(SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT);
if (iBufferSize < iMinBufferSize)
iBufferSize = ((iMinBufferSize / SAMPLES_PER_FRAME) + 1) * SAMPLES_PER_FRAME * 2;
audioRecord = new AudioRecord(AUDIO_SOURCE, SAMPLE_RATE, CHANNEL_CONFIG, AUDIO_FORMAT, iBufferSize);
audioRecord.startRecording();
}
将数据发送到编码器：
public void sendDataFromMic(boolean endOfStream) {
if (endOfStream)
Log.d(TAG, "sendDataFromMic end of stream");
long audioPresentationTimeNs;
byte[] mTempBuffer = new byte[SAMPLES_PER_FRAME];
audioPresentationTimeNs = System.nanoTime();
int iReadResult = audioRecord.read(mTempBuffer, 0, mTempBuffer.length);
if (iReadResult == AudioRecord.ERROR_BAD_VALUE || iReadResult == AudioRecord.ERROR_INVALID_OPERATION || iReadResult == 0) {
Log.e(TAG, "audio buffer read error");
} else {
// send current frame data to encoder
try {
if (inputBuffers == null)
inputBuffers = encoder.getInputBuffers();
//Sometimes can't get any available input buffer
int inputBufferIndex = encoder.dequeueInputBuffer(100000);
Log.d(TAG, "inputBufferIndex = " + inputBufferIndex);
if (inputBufferIndex >= 0) {
inputBuffer = inputBuffers[inputBufferIndex];
inputBuffer.clear();
inputBuffer.put(mTempBuffer, 0, iReadResult);
Log.d(TAG, "sending frame to audio encoder " + iReadResult + " bytes");
encoder.queueInputBuffer(inputBufferIndex, 0, iReadResult, audioPresentationTimeNs / 1000,
endOfStream ? MediaCodec.BUFFER_FLAG_END_OF_STREAM : 0);
}
} catch (Throwable t) {
Log.e(TAG, "sendFrameToAudioEncoder exception");
t.printStackTrace();
}
}
}
排水编码器：
public void drainEncoder() {
ByteBuffer[] encoderOutputBuffers = encoder.getOutputBuffers();
while (true) {
int encoderStatus = encoder.dequeueOutputBuffer(bufferInfo, TIMEOUT_NSECS);
if (encoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
Log.d(TAG, "no output available, spinning to await EOS");
break;
} else if (encoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED)
encoderOutputBuffers = encoder.getOutputBuffers();
else if (encoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
MediaFormat newFormat = encoder.getOutputFormat();
Log.d(TAG, "encoder format changed: " + newFormat);
trackIndex = muxer.addTrack(newFormat);
} else if (muxer.isMuxerStarted()) {
ByteBuffer encodedData = encoderOutputBuffers[encoderStatus];
if (encodedData == null)
throw new RuntimeException("encoded buffer " + encoderStatus + " was null");
if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
Log.d(TAG, "ignoring BUFFER_FLAG_CODEC_CONFIG");
bufferInfo.size = 0;
}
if (bufferInfo.size != 0) {
encodedData.position(bufferInfo.offset);
encodedData.limit(bufferInfo.offset + bufferInfo.size);
muxer.writeSampleData(trackIndex, encodedData, bufferInfo);
Log.d(TAG, "sent " + bufferInfo.size + " bytes to muxer, ts=" +
bufferInfo.presentationTimeUs + " track index=" + trackIndex);
}
encoder.releaseOutputBuffer(encoderStatus, false);
if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
Log.d(TAG, "end of stream reached");
completed = true;
break; // out of while
}
}
}
}
Bug在HTC One，Galaxy S3上再现稳定，但在华为荣耀3C上一切正常。
答案 0 :(得分：1)
在源代码调查后，我找到了解决方案。当我使输出缓冲区出列时，复用器可能尚未启动，在这种情况下缓冲区未释放。所以这里是排水编码器的工作代码：
public void drainEncoder() {
ByteBuffer[] encoderOutputBuffers = encoder.getOutputBuffers();
while (true) {
int encoderStatus = encoder.dequeueOutputBuffer(bufferInfo, TIMEOUT_NSECS);
if (encoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
Log.d(TAG, "no output available, spinning to await EOS");
break;
} else if (encoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED)
encoderOutputBuffers = encoder.getOutputBuffers();
else if (encoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
MediaFormat newFormat = encoder.getOutputFormat();
Log.d(TAG, "encoder format changed: " + newFormat);
trackIndex = muxer.addTrack(newFormat);
} else if (muxer.isMuxerStarted()) {
ByteBuffer encodedData = encoderOutputBuffers[encoderStatus];
if (encodedData == null)
throw new RuntimeException("encoded buffer " + encoderStatus + " was null");
if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG) != 0) {
Log.d(TAG, "ignoring BUFFER_FLAG_CODEC_CONFIG");
bufferInfo.size = 0;
}
if (bufferInfo.size != 0) {
encodedData.position(bufferInfo.offset);
encodedData.limit(bufferInfo.offset + bufferInfo.size);
muxer.writeSampleData(trackIndex, encodedData, bufferInfo);
Log.d(TAG, "sent " + bufferInfo.size + " bytes to muxer, ts=" +
bufferInfo.presentationTimeUs + " track index=" + trackIndex);
}
encoder.releaseOutputBuffer(encoderStatus, false);
if ((bufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
Log.d(TAG, "end of stream reached");
completed = true;
break; // out of while
}
}
else{
//Muxer not ready, release buffer
encoder.releaseOutputBuffer(encoderStatus, false);
Log.d(TAG, "muxer not ready, skip data");
}
}
}