我正在寻找减少视频重量的有效方法(作为 File，用于上传)，显而易见的答案是:让我们降低分辨率! (不需要全高清或 4K，简单的高清对我来说就足够了)我已经尝试了很多应该通过很多 API(需要 10 个)工作的方法，最好的方法是使用 android-ffmpeg-java ，但是......在我相当快的几乎当前的旗舰设备上，整个过程持续了大约 length_of_video*4 秒，而且这个 lib 重量是 9 Mb，这个数量增加了我的应用程序大小......不! (12 Mb 到 1 Mb 是不错的结果，但仍然有太多缺陷)
所以我决定使用 native Android 方式来执行此操作，MediaMuxer 和 MediaCodec - 它们分别可从 API18 和 API16 获得(旧设备用户:抱歉；但他们也经常有“低分辨率”相机)。下面的方法几乎有效——MediaMuxer不遵守MediaFormat.KEY_WIDTH和MediaFormat.KEY_HEIGHT——提取的文件 被“重新压缩”，权重稍微小了一点，但分辨率与原始视频相同 File...
那么，问题是:如何使用 MediaMuxer 和其他随附的类和方法来压缩和重新缩放/更改视频的分辨率？
public File getCompressedFile(String videoPath) throws IOException{
MediaExtractor extractor = new MediaExtractor();
extractor.setDataSource(videoPath);
int trackCount = extractor.getTrackCount();
String filePath = videoPath.substring(0, videoPath.lastIndexOf(File.separator));
String[] splitByDot = videoPath.split("\\.");
String ext="";
if(splitByDot!=null && splitByDot.length>1)
ext = splitByDot[splitByDot.length-1];
String fileName = videoPath.substring(videoPath.lastIndexOf(File.separator)+1,
videoPath.length());
if(ext.length()>0)
fileName=fileName.replace("."+ext, "_out."+ext);
else
fileName=fileName.concat("_out");
final File outFile = new File(filePath, fileName);
if(!outFile.exists())
outFile.createNewFile();
MediaMuxer muxer = new MediaMuxer(outFile.getAbsolutePath(),
MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
HashMap<Integer, Integer> indexMap = new HashMap<Integer, Integer>(trackCount);
for (int i = 0; i < trackCount; i++) {
extractor.selectTrack(i);
MediaFormat format = extractor.getTrackFormat(i);
String mime = format.getString(MediaFormat.KEY_MIME);
if(mime!=null && mime.startsWith("video")){
int currWidth = format.getInteger(MediaFormat.KEY_WIDTH);
int currHeight = format.getInteger(MediaFormat.KEY_HEIGHT);
format.setInteger(MediaFormat.KEY_WIDTH, currWidth>currHeight ? 960 : 540);
format.setInteger(MediaFormat.KEY_HEIGHT, currWidth>currHeight ? 540 : 960);
//API19 MediaFormat.KEY_MAX_WIDTH and KEY_MAX_HEIGHT
format.setInteger("max-width", format.getInteger(MediaFormat.KEY_WIDTH));
format.setInteger("max-height", format.getInteger(MediaFormat.KEY_HEIGHT));
}
int dstIndex = muxer.addTrack(format);
indexMap.put(i, dstIndex);
}
boolean sawEOS = false;
int bufferSize = 256 * 1024;
int offset = 100;
ByteBuffer dstBuf = ByteBuffer.allocate(bufferSize);
MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();
muxer.start();
while (!sawEOS) {
bufferInfo.offset = offset;
bufferInfo.size = extractor.readSampleData(dstBuf, offset);
if (bufferInfo.size < 0) {
sawEOS = true;
bufferInfo.size = 0;
} else {
bufferInfo.presentationTimeUs = extractor.getSampleTime();
bufferInfo.flags = extractor.getSampleFlags();
int trackIndex = extractor.getSampleTrackIndex();
muxer.writeSampleData(indexMap.get(trackIndex), dstBuf,
bufferInfo);
extractor.advance();
}
}
muxer.stop();
muxer.release();
return outFile;
}
附言。关于 muxer 的很多有用的东西 here ，以上代码基于MediaMuxerTest.java，方法cloneMediaUsingMuxer
最佳答案
基于 bigflake.com/mediacodec/(有关媒体类知识的绝佳来源)我尝试了几种方法，最终 ExtractDecodeEditEncodeMuxTest 非常有帮助。 bigflake 站点上的文章中没有描述此测试，但可以在文本中提到的其他类旁边找到 HERE。
所以，我从上面提到的 ExtractDecodeEditEncodeMuxTest 类中复制了大部分代码，它就是:VideoResolutionChanger。它为我提供了 16 Mb 全高清的 2Mb 高清视频。好的!而且快!在我的设备上，整个过程比输入视频持续时间长一点，例如10 秒视频输入 -> 11-12 秒处理。使用 ffmpeg-java 大约需要 40 秒或更多(应用程序需要 9 Mb 以上)。
开始吧:
VideoResolutionChanger:
@TargetApi(18)
public class VideoResolutionChanger {
private static final int TIMEOUT_USEC = 10000;
private static final String OUTPUT_VIDEO_MIME_TYPE = "video/avc";
private static final int OUTPUT_VIDEO_BIT_RATE = 2048 * 1024;
private static final int OUTPUT_VIDEO_FRAME_RATE = 30;
private static final int OUTPUT_VIDEO_IFRAME_INTERVAL = 10;
private static final int OUTPUT_VIDEO_COLOR_FORMAT =
MediaCodecInfo.CodecCapabilities.COLOR_FormatSurface;
private static final String OUTPUT_AUDIO_MIME_TYPE = "audio/mp4a-latm";
private static final int OUTPUT_AUDIO_CHANNEL_COUNT = 2;
private static final int OUTPUT_AUDIO_BIT_RATE = 128 * 1024;
private static final int OUTPUT_AUDIO_AAC_PROFILE =
MediaCodecInfo.CodecProfileLevel.AACObjectHE;
private static final int OUTPUT_AUDIO_SAMPLE_RATE_HZ = 44100;
private int mWidth = 1280;
private int mHeight = 720;
private String mOutputFile, mInputFile;
public String changeResolution(File f)
throws Throwable {
mInputFile=f.getAbsolutePath();
String filePath = mInputFile.substring(0, mInputFile.lastIndexOf(File.separator));
String[] splitByDot = mInputFile.split("\\.");
String ext="";
if(splitByDot!=null && splitByDot.length>1)
ext = splitByDot[splitByDot.length-1];
String fileName = mInputFile.substring(mInputFile.lastIndexOf(File.separator)+1,
mInputFile.length());
if(ext.length()>0)
fileName=fileName.replace("."+ext, "_out.mp4");
else
fileName=fileName.concat("_out.mp4");
final File outFile = new File(Environment.getExternalStorageDirectory(), fileName);
if(!outFile.exists())
outFile.createNewFile();
mOutputFile=outFile.getAbsolutePath();
ChangerWrapper.changeResolutionInSeparatedThread(this);
return mOutputFile;
}
private static class ChangerWrapper implements Runnable {
private Throwable mThrowable;
private VideoResolutionChanger mChanger;
private ChangerWrapper(VideoResolutionChanger changer) {
mChanger = changer;
}
@Override
public void run() {
try {
mChanger.prepareAndChangeResolution();
} catch (Throwable th) {
mThrowable = th;
}
}
public static void changeResolutionInSeparatedThread(VideoResolutionChanger changer)
throws Throwable {
ChangerWrapper wrapper = new ChangerWrapper(changer);
Thread th = new Thread(wrapper, ChangerWrapper.class.getSimpleName());
th.start();
th.join();
if (wrapper.mThrowable != null)
throw wrapper.mThrowable;
}
}
private void prepareAndChangeResolution() throws Exception {
Exception exception = null;
MediaCodecInfo videoCodecInfo = selectCodec(OUTPUT_VIDEO_MIME_TYPE);
if (videoCodecInfo == null)
return;
MediaCodecInfo audioCodecInfo = selectCodec(OUTPUT_AUDIO_MIME_TYPE);
if (audioCodecInfo == null)
return;
MediaExtractor videoExtractor = null;
MediaExtractor audioExtractor = null;
OutputSurface outputSurface = null;
MediaCodec videoDecoder = null;
MediaCodec audioDecoder = null;
MediaCodec videoEncoder = null;
MediaCodec audioEncoder = null;
MediaMuxer muxer = null;
InputSurface inputSurface = null;
try {
videoExtractor = createExtractor();
int videoInputTrack = getAndSelectVideoTrackIndex(videoExtractor);
MediaFormat inputFormat = videoExtractor.getTrackFormat(videoInputTrack);
MediaMetadataRetriever m = new MediaMetadataRetriever();
m.setDataSource(mInputFile);
int inputWidth, inputHeight;
try {
inputWidth = Integer.parseInt(m.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH));
inputHeight = Integer.parseInt(m.extractMetadata(MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT));
} catch (Exception e) {
Bitmap thumbnail = m.getFrameAtTime();
inputWidth = thumbnail.getWidth();
inputHeight = thumbnail.getHeight();
thumbnail.recycle();
}
if(inputWidth>inputHeight){
if(mWidth<mHeight){
int w = mWidth;
mWidth=mHeight;
mHeight=w;
}
}
else{
if(mWidth>mHeight){
int w = mWidth;
mWidth=mHeight;
mHeight=w;
}
}
MediaFormat outputVideoFormat =
MediaFormat.createVideoFormat(OUTPUT_VIDEO_MIME_TYPE, mWidth, mHeight);
outputVideoFormat.setInteger(
MediaFormat.KEY_COLOR_FORMAT, OUTPUT_VIDEO_COLOR_FORMAT);
outputVideoFormat.setInteger(MediaFormat.KEY_BIT_RATE, OUTPUT_VIDEO_BIT_RATE);
outputVideoFormat.setInteger(MediaFormat.KEY_FRAME_RATE, OUTPUT_VIDEO_FRAME_RATE);
outputVideoFormat.setInteger(
MediaFormat.KEY_I_FRAME_INTERVAL, OUTPUT_VIDEO_IFRAME_INTERVAL);
AtomicReference<Surface> inputSurfaceReference = new AtomicReference<Surface>();
videoEncoder = createVideoEncoder(
videoCodecInfo, outputVideoFormat, inputSurfaceReference);
inputSurface = new InputSurface(inputSurfaceReference.get());
inputSurface.makeCurrent();
outputSurface = new OutputSurface();
videoDecoder = createVideoDecoder(inputFormat, outputSurface.getSurface());
audioExtractor = createExtractor();
int audioInputTrack = getAndSelectAudioTrackIndex(audioExtractor);
MediaFormat inputAudioFormat = audioExtractor.getTrackFormat(audioInputTrack);
MediaFormat outputAudioFormat =
MediaFormat.createAudioFormat(inputAudioFormat.getString(MediaFormat.KEY_MIME),
inputAudioFormat.getInteger(MediaFormat.KEY_SAMPLE_RATE),
inputAudioFormat.getInteger(MediaFormat.KEY_CHANNEL_COUNT));
outputAudioFormat.setInteger(MediaFormat.KEY_BIT_RATE, OUTPUT_AUDIO_BIT_RATE);
outputAudioFormat.setInteger(MediaFormat.KEY_AAC_PROFILE, OUTPUT_AUDIO_AAC_PROFILE);
audioEncoder = createAudioEncoder(audioCodecInfo, outputAudioFormat);
audioDecoder = createAudioDecoder(inputAudioFormat);
muxer = new MediaMuxer(mOutputFile, MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4);
changeResolution(videoExtractor, audioExtractor,
videoDecoder, videoEncoder,
audioDecoder, audioEncoder,
muxer, inputSurface, outputSurface);
} finally {
try {
if (videoExtractor != null)
videoExtractor.release();
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (audioExtractor != null)
audioExtractor.release();
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (videoDecoder != null) {
videoDecoder.stop();
videoDecoder.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (outputSurface != null) {
outputSurface.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (videoEncoder != null) {
videoEncoder.stop();
videoEncoder.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (audioDecoder != null) {
audioDecoder.stop();
audioDecoder.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (audioEncoder != null) {
audioEncoder.stop();
audioEncoder.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (muxer != null) {
muxer.stop();
muxer.release();
}
} catch(Exception e) {
if (exception == null)
exception = e;
}
try {
if (inputSurface != null)
inputSurface.release();
} catch(Exception e) {
if (exception == null)
exception = e;
}
}
if (exception != null)
throw exception;
}
private MediaExtractor createExtractor() throws IOException {
MediaExtractor extractor;
extractor = new MediaExtractor();
extractor.setDataSource(mInputFile);
return extractor;
}
private MediaCodec createVideoDecoder(MediaFormat inputFormat, Surface surface) throws IOException {
MediaCodec decoder = MediaCodec.createDecoderByType(getMimeTypeFor(inputFormat));
decoder.configure(inputFormat, surface, null, 0);
decoder.start();
return decoder;
}
private MediaCodec createVideoEncoder(MediaCodecInfo codecInfo, MediaFormat format,
AtomicReference<Surface> surfaceReference) throws IOException {
MediaCodec encoder = MediaCodec.createByCodecName(codecInfo.getName());
encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
surfaceReference.set(encoder.createInputSurface());
encoder.start();
return encoder;
}
private MediaCodec createAudioDecoder(MediaFormat inputFormat) throws IOException {
MediaCodec decoder = MediaCodec.createDecoderByType(getMimeTypeFor(inputFormat));
decoder.configure(inputFormat, null, null, 0);
decoder.start();
return decoder;
}
private MediaCodec createAudioEncoder(MediaCodecInfo codecInfo, MediaFormat format) throws IOException {
MediaCodec encoder = MediaCodec.createByCodecName(codecInfo.getName());
encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
encoder.start();
return encoder;
}
private int getAndSelectVideoTrackIndex(MediaExtractor extractor) {
for (int index = 0; index < extractor.getTrackCount(); ++index) {
if (isVideoFormat(extractor.getTrackFormat(index))) {
extractor.selectTrack(index);
return index;
}
}
return -1;
}
private int getAndSelectAudioTrackIndex(MediaExtractor extractor) {
for (int index = 0; index < extractor.getTrackCount(); ++index) {
if (isAudioFormat(extractor.getTrackFormat(index))) {
extractor.selectTrack(index);
return index;
}
}
return -1;
}
private void changeResolution(MediaExtractor videoExtractor, MediaExtractor audioExtractor,
MediaCodec videoDecoder, MediaCodec videoEncoder,
MediaCodec audioDecoder, MediaCodec audioEncoder,
MediaMuxer muxer,
InputSurface inputSurface, OutputSurface outputSurface) {
ByteBuffer[] videoDecoderInputBuffers = null;
ByteBuffer[] videoDecoderOutputBuffers = null;
ByteBuffer[] videoEncoderOutputBuffers = null;
MediaCodec.BufferInfo videoDecoderOutputBufferInfo = null;
MediaCodec.BufferInfo videoEncoderOutputBufferInfo = null;
videoDecoderInputBuffers = videoDecoder.getInputBuffers();
videoDecoderOutputBuffers = videoDecoder.getOutputBuffers();
videoEncoderOutputBuffers = videoEncoder.getOutputBuffers();
videoDecoderOutputBufferInfo = new MediaCodec.BufferInfo();
videoEncoderOutputBufferInfo = new MediaCodec.BufferInfo();
ByteBuffer[] audioDecoderInputBuffers = null;
ByteBuffer[] audioDecoderOutputBuffers = null;
ByteBuffer[] audioEncoderInputBuffers = null;
ByteBuffer[] audioEncoderOutputBuffers = null;
MediaCodec.BufferInfo audioDecoderOutputBufferInfo = null;
MediaCodec.BufferInfo audioEncoderOutputBufferInfo = null;
audioDecoderInputBuffers = audioDecoder.getInputBuffers();
audioDecoderOutputBuffers = audioDecoder.getOutputBuffers();
audioEncoderInputBuffers = audioEncoder.getInputBuffers();
audioEncoderOutputBuffers = audioEncoder.getOutputBuffers();
audioDecoderOutputBufferInfo = new MediaCodec.BufferInfo();
audioEncoderOutputBufferInfo = new MediaCodec.BufferInfo();
MediaFormat decoderOutputVideoFormat = null;
MediaFormat decoderOutputAudioFormat = null;
MediaFormat encoderOutputVideoFormat = null;
MediaFormat encoderOutputAudioFormat = null;
int outputVideoTrack = -1;
int outputAudioTrack = -1;
boolean videoExtractorDone = false;
boolean videoDecoderDone = false;
boolean videoEncoderDone = false;
boolean audioExtractorDone = false;
boolean audioDecoderDone = false;
boolean audioEncoderDone = false;
int pendingAudioDecoderOutputBufferIndex = -1;
boolean muxing = false;
while ((!videoEncoderDone) || (!audioEncoderDone)) {
while (!videoExtractorDone
&& (encoderOutputVideoFormat == null || muxing)) {
int decoderInputBufferIndex = videoDecoder.dequeueInputBuffer(TIMEOUT_USEC);
if (decoderInputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER)
break;
ByteBuffer decoderInputBuffer = videoDecoderInputBuffers[decoderInputBufferIndex];
int size = videoExtractor.readSampleData(decoderInputBuffer, 0);
long presentationTime = videoExtractor.getSampleTime();
if (size >= 0) {
videoDecoder.queueInputBuffer(
decoderInputBufferIndex,
0,
size,
presentationTime,
videoExtractor.getSampleFlags());
}
videoExtractorDone = !videoExtractor.advance();
if (videoExtractorDone)
videoDecoder.queueInputBuffer(decoderInputBufferIndex,
0, 0, 0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
break;
}
while (!audioExtractorDone
&& (encoderOutputAudioFormat == null || muxing)) {
int decoderInputBufferIndex = audioDecoder.dequeueInputBuffer(TIMEOUT_USEC);
if (decoderInputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER)
break;
ByteBuffer decoderInputBuffer = audioDecoderInputBuffers[decoderInputBufferIndex];
int size = audioExtractor.readSampleData(decoderInputBuffer, 0);
long presentationTime = audioExtractor.getSampleTime();
if (size >= 0)
audioDecoder.queueInputBuffer(decoderInputBufferIndex, 0, size,
presentationTime, audioExtractor.getSampleFlags());
audioExtractorDone = !audioExtractor.advance();
if (audioExtractorDone)
audioDecoder.queueInputBuffer(decoderInputBufferIndex, 0, 0,
0, MediaCodec.BUFFER_FLAG_END_OF_STREAM);
break;
}
while (!videoDecoderDone
&& (encoderOutputVideoFormat == null || muxing)) {
int decoderOutputBufferIndex =
videoDecoder.dequeueOutputBuffer(
videoDecoderOutputBufferInfo, TIMEOUT_USEC);
if (decoderOutputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER)
break;
if (decoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
videoDecoderOutputBuffers = videoDecoder.getOutputBuffers();
break;
}
if (decoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
decoderOutputVideoFormat = videoDecoder.getOutputFormat();
break;
}
ByteBuffer decoderOutputBuffer =
videoDecoderOutputBuffers[decoderOutputBufferIndex];
if ((videoDecoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG)
!= 0) {
videoDecoder.releaseOutputBuffer(decoderOutputBufferIndex, false);
break;
}
boolean render = videoDecoderOutputBufferInfo.size != 0;
videoDecoder.releaseOutputBuffer(decoderOutputBufferIndex, render);
if (render) {
outputSurface.awaitNewImage();
outputSurface.drawImage();
inputSurface.setPresentationTime(
videoDecoderOutputBufferInfo.presentationTimeUs * 1000);
inputSurface.swapBuffers();
}
if ((videoDecoderOutputBufferInfo.flags
& MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0) {
videoDecoderDone = true;
videoEncoder.signalEndOfInputStream();
}
break;
}
while (!audioDecoderDone && pendingAudioDecoderOutputBufferIndex == -1
&& (encoderOutputAudioFormat == null || muxing)) {
int decoderOutputBufferIndex =
audioDecoder.dequeueOutputBuffer(
audioDecoderOutputBufferInfo, TIMEOUT_USEC);
if (decoderOutputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER)
break;
if (decoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
audioDecoderOutputBuffers = audioDecoder.getOutputBuffers();
break;
}
if (decoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
decoderOutputAudioFormat = audioDecoder.getOutputFormat();
break;
}
ByteBuffer decoderOutputBuffer =
audioDecoderOutputBuffers[decoderOutputBufferIndex];
if ((audioDecoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG)
!= 0) {
audioDecoder.releaseOutputBuffer(decoderOutputBufferIndex, false);
break;
}
pendingAudioDecoderOutputBufferIndex = decoderOutputBufferIndex;
break;
}
while (pendingAudioDecoderOutputBufferIndex != -1) {
int encoderInputBufferIndex = audioEncoder.dequeueInputBuffer(TIMEOUT_USEC);
ByteBuffer encoderInputBuffer = audioEncoderInputBuffers[encoderInputBufferIndex];
int size = audioDecoderOutputBufferInfo.size;
long presentationTime = audioDecoderOutputBufferInfo.presentationTimeUs;
if (size >= 0) {
ByteBuffer decoderOutputBuffer =
audioDecoderOutputBuffers[pendingAudioDecoderOutputBufferIndex]
.duplicate();
decoderOutputBuffer.position(audioDecoderOutputBufferInfo.offset);
decoderOutputBuffer.limit(audioDecoderOutputBufferInfo.offset + size);
encoderInputBuffer.position(0);
encoderInputBuffer.put(decoderOutputBuffer);
audioEncoder.queueInputBuffer(
encoderInputBufferIndex,
0,
size,
presentationTime,
audioDecoderOutputBufferInfo.flags);
}
audioDecoder.releaseOutputBuffer(pendingAudioDecoderOutputBufferIndex, false);
pendingAudioDecoderOutputBufferIndex = -1;
if ((audioDecoderOutputBufferInfo.flags
& MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0)
audioDecoderDone = true;
break;
}
while (!videoEncoderDone
&& (encoderOutputVideoFormat == null || muxing)) {
int encoderOutputBufferIndex = videoEncoder.dequeueOutputBuffer(
videoEncoderOutputBufferInfo, TIMEOUT_USEC);
if (encoderOutputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER)
break;
if (encoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
videoEncoderOutputBuffers = videoEncoder.getOutputBuffers();
break;
}
if (encoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
encoderOutputVideoFormat = videoEncoder.getOutputFormat();
break;
}
ByteBuffer encoderOutputBuffer =
videoEncoderOutputBuffers[encoderOutputBufferIndex];
if ((videoEncoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG)
!= 0) {
videoEncoder.releaseOutputBuffer(encoderOutputBufferIndex, false);
break;
}
if (videoEncoderOutputBufferInfo.size != 0) {
muxer.writeSampleData(
outputVideoTrack, encoderOutputBuffer, videoEncoderOutputBufferInfo);
}
if ((videoEncoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM)
!= 0) {
videoEncoderDone = true;
}
videoEncoder.releaseOutputBuffer(encoderOutputBufferIndex, false);
break;
}
while (!audioEncoderDone
&& (encoderOutputAudioFormat == null || muxing)) {
int encoderOutputBufferIndex = audioEncoder.dequeueOutputBuffer(
audioEncoderOutputBufferInfo, TIMEOUT_USEC);
if (encoderOutputBufferIndex == MediaCodec.INFO_TRY_AGAIN_LATER) {
break;
}
if (encoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED) {
audioEncoderOutputBuffers = audioEncoder.getOutputBuffers();
break;
}
if (encoderOutputBufferIndex == MediaCodec.INFO_OUTPUT_FORMAT_CHANGED) {
encoderOutputAudioFormat = audioEncoder.getOutputFormat();
break;
}
ByteBuffer encoderOutputBuffer =
audioEncoderOutputBuffers[encoderOutputBufferIndex];
if ((audioEncoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_CODEC_CONFIG)
!= 0) {
audioEncoder.releaseOutputBuffer(encoderOutputBufferIndex, false);
break;
}
if (audioEncoderOutputBufferInfo.size != 0)
muxer.writeSampleData(
outputAudioTrack, encoderOutputBuffer, audioEncoderOutputBufferInfo);
if ((audioEncoderOutputBufferInfo.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM)
!= 0)
audioEncoderDone = true;
audioEncoder.releaseOutputBuffer(encoderOutputBufferIndex, false);
break;
}
if (!muxing && (encoderOutputAudioFormat != null)
&& (encoderOutputVideoFormat != null)) {
outputVideoTrack = muxer.addTrack(encoderOutputVideoFormat);
outputAudioTrack = muxer.addTrack(encoderOutputAudioFormat);
muxer.start();
muxing = true;
}
}
}
private static boolean isVideoFormat(MediaFormat format) {
return getMimeTypeFor(format).startsWith("video/");
}
private static boolean isAudioFormat(MediaFormat format) {
return getMimeTypeFor(format).startsWith("audio/");
}
private static String getMimeTypeFor(MediaFormat format) {
return format.getString(MediaFormat.KEY_MIME);
}
private static MediaCodecInfo selectCodec(String mimeType) {
int numCodecs = MediaCodecList.getCodecCount();
for (int i = 0; i < numCodecs; i++) {
MediaCodecInfo codecInfo = MediaCodecList.getCodecInfoAt(i);
if (!codecInfo.isEncoder()) {
continue;
}
String[] types = codecInfo.getSupportedTypes();
for (int j = 0; j < types.length; j++) {
if (types[j].equalsIgnoreCase(mimeType)) {
return codecInfo;
}
}
}
return null;
}
}
它还需要 InputSurface、OutputSurface 和 TextureRender，它们位于 ExtractDecodeEditEncodeMuxTest 旁边(HERE 链接上方).将这三个与 VideoResolutionChanger 放在同一个包中并像这样使用它:
try{
String pathToReEncodedFile =
new VideoResolutionChanger().changeResolution(videoFilePath);
}catch(Throwable t){/* smth wrong :( */}
可以使用 file.getAbsolutePath() 从 File 获取 videoFilePath。
我知道这不是最干净的方法，也可能不是最有效/最有效的方法，但过去两天我一直在寻找类似的代码并找到了很多主题，其中大部分将我重定向到 INDE、ffmpeg 或 jcodec，其他没有得到正确的答案。所以我把它留在这里，明智地使用它!
限制:
- 上面的 use-it-like-this 代码段不能在主循环线程 (ui) 中启动，例如直接在
Activity中。最好的方法是将 createIntentService和 pass 输入文件路径StringinIntents extraBundle。然后你可以直接在onHandleIntent中运行changeResolution; - API18及以上(引入了
MediaMuxer)； - API18当然需要
WRITE_EXTERNAL_STORAGE，API19及以上版本都有这个“内置”；
@fadden 感谢的工作和支持! :)
关于android - MediaMuxer 视频文件大小减小(重新压缩，降低分辨率)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29943121/