下面列出了android.media.MediaExtractor#getSampleTrackIndex ( ) 实例代码，或者点击链接到github查看源代码，也可以在右侧发表评论。
public static void seekToLastFrame(MediaExtractor extractor, int trackIndex, int durationMs) {
int seekToDuration = durationMs * 1000;
if (extractor.getSampleTrackIndex() != trackIndex) {
extractor.selectTrack(trackIndex);
}
extractor.seekTo(seekToDuration, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
while (seekToDuration > 0 && extractor.getSampleTrackIndex() != trackIndex) {
seekToDuration -= 10000;
extractor.seekTo(seekToDuration, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
while (!inputDone) {
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size < 0) {
info.size = 0;
eof = true;
} else {
info.presentationTimeUs = extractor.getSampleTime();
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
// didWriteData(messageObject, file, false, false);
}
extractor.advance();
} else {
eof = true;
}
}
} else if (index == -1) {
eof = true;
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
while (!inputDone) {
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size < 0) {
info.size = 0;
eof = true;
} else {
info.presentationTimeUs = extractor.getSampleTime();
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
// didWriteData(messageObject, file, false, false);
}
extractor.advance();
} else {
eof = true;
}
}
} else if (index == -1) {
eof = true;
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
while (!inputDone) {
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size < 0) {
info.size = 0;
eof = true;
} else {
info.presentationTimeUs = extractor.getSampleTime();
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
// didWriteData(messageObject, file, false, false);
}
extractor.advance();
} else {
eof = true;
}
}
} else if (index == -1) {
eof = true;
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
while (!inputDone) {
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size < 0) {
info.size = 0;
eof = true;
} else {
info.presentationTimeUs = extractor.getSampleTime();
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
// didWriteData(messageObject, file, false, false);
}
extractor.advance();
} else {
eof = true;
}
}
} else if (index == -1) {
eof = true;
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
while (!inputDone) {
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size < 0) {
info.size = 0;
eof = true;
} else {
info.presentationTimeUs = extractor.getSampleTime();
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
// didWriteData(messageObject, file, false, false);
}
extractor.advance();
} else {
eof = true;
}
}
} else if (index == -1) {
eof = true;
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}
/**
* Work loop.
*/
static void doExtract(MediaExtractor extractor, int trackIndex, MediaCodec decoder,
CodecOutputSurface outputSurface) throws IOException {
final int TIMEOUT_USEC = 10000;
ByteBuffer[] decoderInputBuffers = decoder.getInputBuffers();
MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
int inputChunk = 0;
int decodeCount = 0;
long frameSaveTime = 0;
boolean outputDone = false;
boolean inputDone = false;
while (!outputDone) {
if (VERBOSE) Log.d(TAG, "loop");
// Feed more data to the decoder.
if (!inputDone) {
int inputBufIndex = decoder.dequeueInputBuffer(TIMEOUT_USEC);
if (inputBufIndex >= 0) {
ByteBuffer inputBuf = decoderInputBuffers[inputBufIndex];
// Read the sample data into the ByteBuffer. This neither respects nor
// updates inputBuf's position, limit, etc.
int chunkSize = extractor.readSampleData(inputBuf, 0);
if (chunkSize < 0) {
// End of stream -- send empty frame with EOS flag set.
decoder.queueInputBuffer(inputBufIndex, 0, 0, 0L,
MediaCodec.BUFFER_FLAG_END_OF_STREAM);
inputDone = true;
if (VERBOSE) Log.d(TAG, "sent input EOS");
} else {
if (extractor.getSampleTrackIndex() != trackIndex) {
Log.w(TAG, "WEIRD: got sample from track " +
extractor.getSampleTrackIndex() + ", expected " + trackIndex);
}
long presentationTimeUs = extractor.getSampleTime();
decoder.queueInputBuffer(inputBufIndex, 0, chunkSize,
presentationTimeUs, 0 /*flags*/);
if (VERBOSE) {
Log.d(TAG, "submitted frame " + inputChunk + " to dec, size=" +
chunkSize);
}
inputChunk++;
extractor.advance();
}
} else {
if (VERBOSE) Log.d(TAG, "input buffer not available");
}
}
if (!outputDone) {
int decoderStatus = decoder.dequeueOutputBuffer(info, TIMEOUT_USEC);
if (decoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
// no output available yet
if (VERBOSE) Log.d(TAG, "no output from decoder available");
} else if (decoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
// not important for us, since we're using Surface
if (VERBOSE) Log.d(TAG, "decoder output buffers changed");
} else if (decoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
MediaFormat newFormat = decoder.getOutputFormat();
if (VERBOSE) Log.d(TAG, "decoder output format changed: " + newFormat);
} else if (decoderStatus < 0) {
fail("unexpected result from decoder.dequeueOutputBuffer: " + decoderStatus);
} else { // decoderStatus >= 0
if (VERBOSE) Log.d(TAG, "surface decoder given buffer " + decoderStatus +
" (size=" + info.size + ")");
if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
if (VERBOSE) Log.d(TAG, "output EOS");
outputDone = true;
}
boolean doRender = (info.size != 0);
// As soon as we call releaseOutputBuffer, the buffer will be forwarded
// to SurfaceTexture to convert to a texture. The API doesn't guarantee
// that the texture will be available before the call returns, so we
// need to wait for the onFrameAvailable callback to fire.
decoder.releaseOutputBuffer(decoderStatus, doRender);
if (doRender) {
if (VERBOSE) Log.d(TAG, "awaiting decode of frame " + decodeCount);
outputSurface.awaitNewImage();
outputSurface.drawImage(true);
if (decodeCount < MAX_FRAMES) {
File outputFile = new File(FILES_DIR,
String.format("frame-%02d.png", decodeCount));
long startWhen = System.nanoTime();
outputSurface.saveFrame(outputFile.toString());
frameSaveTime += System.nanoTime() - startWhen;
}
decodeCount++;
}
}
}
}
int numSaved = (MAX_FRAMES < decodeCount) ? MAX_FRAMES : decodeCount;
Log.d(TAG, "Saving " + numSaved + " frames took " +
(frameSaveTime / numSaved / 1000) + " us per frame");
}
/**
* Work loop.
*/
static void doExtract(MediaExtractor extractor, int trackIndex, MediaCodec decoder,
CodecOutputSurface outputSurface) throws IOException {
final int TIMEOUT_USEC = 10000;
ByteBuffer[] decoderInputBuffers = decoder.getInputBuffers();
MediaCodec.BufferInfo info = new MediaCodec.BufferInfo();
int inputChunk = 0;
int decodeCount = 0;
long frameSaveTime = 0;
boolean outputDone = false;
boolean inputDone = false;
while (!outputDone) {
if (VERBOSE) Log.d(TAG, "loop");
// Feed more data to the decoder.
if (!inputDone) {
int inputBufIndex = decoder.dequeueInputBuffer(TIMEOUT_USEC);
if (inputBufIndex >= 0) {
ByteBuffer inputBuf = decoderInputBuffers[inputBufIndex];
// Read the sample data into the ByteBuffer. This neither respects nor
// updates inputBuf's position, limit, etc.
int chunkSize = extractor.readSampleData(inputBuf, 0);
if (chunkSize < 0) {
// End of stream -- send empty frame with EOS flag set.
decoder.queueInputBuffer(inputBufIndex, 0, 0, 0L,
MediaCodec.BUFFER_FLAG_END_OF_STREAM);
inputDone = true;
if (VERBOSE) Log.d(TAG, "sent input EOS");
} else {
if (extractor.getSampleTrackIndex() != trackIndex) {
Log.w(TAG, "WEIRD: got sample from track " +
extractor.getSampleTrackIndex() + ", expected " + trackIndex);
}
long presentationTimeUs = extractor.getSampleTime();
decoder.queueInputBuffer(inputBufIndex, 0, chunkSize,
presentationTimeUs, 0 /*flags*/);
if (VERBOSE) {
Log.d(TAG, "submitted frame " + inputChunk + " to dec, size=" +
chunkSize);
}
inputChunk++;
extractor.advance();
}
} else {
if (VERBOSE) Log.d(TAG, "input buffer not available");
}
}
if (!outputDone) {
int decoderStatus = decoder.dequeueOutputBuffer(info, TIMEOUT_USEC);
if (decoderStatus == MediaCodec.INFO_TRY_AGAIN_LATER) {
// no output available yet
if (VERBOSE) Log.d(TAG, "no output from decoder available");
} else if (decoderStatus == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
// not important for us, since we're using Surface
if (VERBOSE) Log.d(TAG, "decoder output buffers changed");
} else if (decoderStatus == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
MediaFormat newFormat = decoder.getOutputFormat();
if (VERBOSE) Log.d(TAG, "decoder output format changed: " + newFormat);
} else if (decoderStatus < 0) {
fail("unexpected result from decoder.dequeueOutputBuffer: " + decoderStatus);
} else { // decoderStatus >= 0
if (VERBOSE) Log.d(TAG, "surface decoder given buffer " + decoderStatus +
" (size=" + info.size + ")");
if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
if (VERBOSE) Log.d(TAG, "output EOS");
outputDone = true;
}
boolean doRender = (info.size != 0);
// As soon as we call releaseOutputBuffer, the buffer will be forwarded
// to SurfaceTexture to convert to a texture. The API doesn't guarantee
// that the texture will be available before the call returns, so we
// need to wait for the onFrameAvailable callback to fire.
decoder.releaseOutputBuffer(decoderStatus, doRender);
if (doRender) {
if (VERBOSE) Log.d(TAG, "awaiting decode of frame " + decodeCount);
outputSurface.awaitNewImage();
outputSurface.drawImage(true);
if (decodeCount < MAX_FRAMES) {
File outputFile = new File(FILES_DIR,
String.format("frame-%02d.png", decodeCount));
long startWhen = System.nanoTime();
outputSurface.saveFrame(outputFile.toString());
frameSaveTime += System.nanoTime() - startWhen;
}
decodeCount++;
}
}
}
}
int numSaved = (MAX_FRAMES < decodeCount) ? MAX_FRAMES : decodeCount;
Log.d(TAG, "Saving " + numSaved + " frames took " +
(frameSaveTime / numSaved / 1000) + " us per frame");
}
@TargetApi(16)
private long readAndWriteTrack(MediaExtractor extractor, MP4Builder mediaMuxer, MediaCodec.BufferInfo info, long start, long end, File file, boolean isAudio) throws Exception {
int trackIndex = selectTrack(extractor, isAudio);
if (trackIndex >= 0) {
extractor.selectTrack(trackIndex);
MediaFormat trackFormat = extractor.getTrackFormat(trackIndex);
int muxerTrackIndex = mediaMuxer.addTrack(trackFormat, isAudio);
int maxBufferSize = trackFormat.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE);
boolean inputDone = false;
if (start > 0) {
extractor.seekTo(start, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
} else {
extractor.seekTo(0, MediaExtractor.SEEK_TO_PREVIOUS_SYNC);
}
ByteBuffer buffer = ByteBuffer.allocateDirect(maxBufferSize);
long startTime = -1;
checkConversionCanceled();
long lastTimestamp = -100;
while (!inputDone) {
checkConversionCanceled();
boolean eof = false;
int index = extractor.getSampleTrackIndex();
if (index == trackIndex) {
info.size = extractor.readSampleData(buffer, 0);
if (info.size >= 0) {
info.presentationTimeUs = extractor.getSampleTime();
} else {
info.size = 0;
eof = true;
}
if (info.size > 0 && !eof) {
if (start > 0 && startTime == -1) {
startTime = info.presentationTimeUs;
}
if (end < 0 || info.presentationTimeUs < end) {
if (info.presentationTimeUs > lastTimestamp) {
info.offset = 0;
info.flags = extractor.getSampleFlags();
if (mediaMuxer.writeSampleData(muxerTrackIndex, buffer, info, isAudio)) {
//didWriteData(messageObject, file, false, false);
}
}
lastTimestamp = info.presentationTimeUs;
} else {
eof = true;
}
}
if (!eof) {
extractor.advance();
}
} else if (index == -1) {
eof = true;
} else {
extractor.advance();
}
if (eof) {
inputDone = true;
}
}
extractor.unselectTrack(trackIndex);
return startTime;
}
return -1;
}