过了一个月了，一直在学习MediaCodec等工具，回头翻了一下上月demux and mux的博客，发现丑到爆炸，于是选择重制，懒得删了。
MediaExtractor 的使用：
在new 一个MediaExtractor的对象后，需要setDataSource,在这里我发现可以不必写到sd卡再设置。
srcFilePath = getResources().openRawResourceFd(R.raw.shape_of_my_heart); extractor.setDataSource(srcFilePath);接下来就是取track并给muxer添加好track
for (int i = 0; i < extractor.getTrackCount(); i++){ MediaFormat format = extractor.getTrackFormat(i); String MIME = format.getString(MediaFormat.KEY_MIME); if (MIME.startsWith("video")){ videoIndex = i; videoInputSize = format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE); continue; } if (MIME.startsWith("audio")){ audioIndex = i; audioInputSize = format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE); } } try { muxer = new MediaMuxer(filePath,MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4); } catch (IOException e) { e.printStackTrace(); } if (0 > videoTrackIndex){ MediaFormat format = extractor.getTrackFormat(videoIndex); videoTrackIndex = muxer.addTrack(format); } if (0 > audioTrackIndex){ MediaFormat format = extractor.getTrackFormat(audioIndex); audioTrackIndex = muxer.addTrack(format); } if (!isMuxerStarted && 0 <= audioTrackIndex && 0 <= videoTrackIndex){ muxer.start(); isMuxerStarted = true; }else{ throw new IllegalArgumentException("muxer track添加失败"); }然后就是塞数据了
MediaFormat format = extractor.getTrackFormat(index); String MIME = format.getString(MediaFormat.KEY_MIME); extractor.selectTrack(index); MediaCodec.BufferInfo info = new MediaCodec.BufferInfo(); while(true) { ByteBuffer inputBuffer = ByteBuffer.allocate(inputSize); int size = extractor.readSampleData(inputBuffer , 0 ); if (0 > size){ Log.v("tag","start release Muxer And Extractor"); break; }else{ info.presentationTimeUs = extractor.getSampleTime(); info.flags = extractor.getSampleFlags(); info.offset = 0; info.size = size; muxer.writeSampleData(trackIndex,inputBuffer,info); extractor.advance(); Log.d("tag","muxing " + MIME); } }然后如果塞数据的操作放在住线程的话，容易因为耗时丢帧，所以建议开线程写
接下来就是完整代码了，感觉上一篇写的真的渣。
demux and mux的核心操作的代码
package com.example.myapplication3; import android.content.res.AssetFileDescriptor; import android.media.MediaCodec; import android.media.MediaExtractor; import android.media.MediaFormat; import android.media.MediaMuxer; import android.util.Log; import java.io.IOException; import java.nio.ByteBuffer; /** * Created by weizheng.huang on 2019-10-31. */ public class DemuxAndMux { private MediaExtractor extractor; private MediaMuxer muxer ; private AssetFileDescriptor srcFilePath; private String filePath; private int videoIndex = -1; private int audioIndex = -1; private int videoTrackIndex = -1; private int audioTrackIndex = -1; private boolean isMuxerStarted = false; private int videoInputSize; private int audioInputSize; public DemuxAndMux(AssetFileDescriptor afd , String filePath){ this.srcFilePath = afd; this.filePath = filePath; } public void init(){ initMediaExtractor(); initMediaMuxer(); } private void initMediaExtractor(){ extractor = new MediaExtractor(); try { extractor.setDataSource(srcFilePath); } catch (IOException e) { e.printStackTrace(); } for (int i = 0; i < extractor.getTrackCount(); i++){ MediaFormat format = extractor.getTrackFormat(i); String MIME = format.getString(MediaFormat.KEY_MIME); if (MIME.startsWith("video")){ videoIndex = i; videoInputSize = format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE); continue; } if (MIME.startsWith("audio")){ audioIndex = i; audioInputSize = format.getInteger(MediaFormat.KEY_MAX_INPUT_SIZE); } } } private void initMediaMuxer(){ try { muxer = new MediaMuxer(filePath,MediaMuxer.OutputFormat.MUXER_OUTPUT_MPEG_4); } catch (IOException e) { e.printStackTrace(); } if (0 > videoTrackIndex){ MediaFormat format = extractor.getTrackFormat(videoIndex); videoTrackIndex = muxer.addTrack(format); } if (0 > audioTrackIndex){ MediaFormat format = extractor.getTrackFormat(audioIndex); audioTrackIndex = muxer.addTrack(format); } } private Thread thread = new Thread(new Runnable() { @Override public void run() { if (!isMuxerStarted && 0 <= audioTrackIndex && 0 <= videoTrackIndex){ muxer.start(); isMuxerStarted = true; }else{ throw new IllegalArgumentException("muxer track添加失败"); } writeIntoBuffer(videoInputSize,videoTrackIndex,videoIndex); writeIntoBuffer(audioInputSize,audioTrackIndex,audioIndex); muxer.stop(); muxer.release(); extractor.release(); Log.v("tag","released muxer and extractor"); } }); public void startDemuxAndMux(){ thread.start(); } private void writeIntoBuffer(int inputSize,int trackIndex , int index){ MediaFormat format = extractor.getTrackFormat(index); String MIME = format.getString(MediaFormat.KEY_MIME); extractor.selectTrack(index); MediaCodec.BufferInfo info = new MediaCodec.BufferInfo(); while(true) { ByteBuffer inputBuffer = ByteBuffer.allocate(inputSize); int size = extractor.readSampleData(inputBuffer , 0 ); if (0 > size){ Log.v("tag","start release Muxer And Extractor"); break; }else{ info.presentationTimeUs = extractor.getSampleTime(); info.flags = extractor.getSampleFlags(); info.offset = 0; info.size = size; muxer.writeSampleData(trackIndex,inputBuffer,info); extractor.advance(); Log.d("tag","muxing " + MIME); } } } }MainActivity的代码,这里只是抽了一部分代码出来，主要是因为项目里还有其他代码不方便拿出来了。
/** * srcFilePath 这里是视频文件路径 类型是AssertFileDescriptor * filePath 这里是sd卡存放路径 */ private DemuxAndMux demuxAndMux = new DemuxAndMux(srcFilePath,filePath); demuxAndMux.init(); muxBtn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { if (verifyPermission(MainActivity.this)) { demuxAndMux.startDemuxAndMux(); } } });
