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private class DecodeThread extends Thread{
private MediaExtractor mMediaExtractor;
private MediaCodec mMediaCodec;
private Surface mSurface;
/*通过构造方法将surface传递进来*/
public DecodeThread(Surface surface){
mSurface = surface;
}
@Override
public void run() {
super.run();
mMediaExtractor = new MediaExtractor();
try {
mMediaExtractor.setDataSource(mFilePath);
} catch (IOException e) {
e.printStackTrace();
}
int trackCount = mMediaExtractor.getTrackCount();
//从媒体提取器中拿到了 MIME 以及MediaFormat 通过MIME 创建的硬件解码器 通过MediaFormat配置的硬件解码器
for (int i = 0; i < trackCount; i++) {
MediaFormat trackFormat = mMediaExtractor.getTrackFormat(i);
Log.d("lpf","trackFormat is "+trackFormat);
String mime=trackFormat.getString(MediaFormat.KEY_MIME);
Log.d("lpf","mime is "+mime);
if (mime.startsWith("video/")){
mMediaExtractor.selectTrack(i);
try {
mMediaCodec=MediaCodec.createDecoderByType(mime);
} catch (IOException e) {
e.printStackTrace();
}
//这样配置之后，解码之后的数据就会 直接显示在mSurface 上边 这里是核心点
mMediaCodec.configure(trackFormat,mSurface,null,0);
break;
}
}
if (mMediaCodec == null){
return;
}
//调用Start 如果没有异常信息，表示成功构建组件
mMediaCodec.start();
ByteBuffer[] inputBuffers = mMediaCodec.getInputBuffers();
ByteBuffer[] outputBuffers = mMediaCodec.getOutputBuffers();
//每个Buffer的元数据包括具体的范围以及偏移大小，以及数据中心相关解码的buffer
MediaCodec.BufferInfo info=new MediaCodec.BufferInfo();
boolean isEOF=false;
long startMs=System.currentTimeMillis();
while (!Thread.interrupted()){//只要线程不中断
if (!isEOF){
//返回有效的buffer 索引，如果没有相关的Buffer可用，就返回-1
//传入的timeoutUs为0表示立即返回
// 如果数据的buffer可用，将无限期等待timeUs的单位是纳秒
int index =mMediaCodec.dequeueInputBuffer(10000);
if (index >= 0){
ByteBuffer byteBuffer=inputBuffers[index];
Log.d("lpf","bytebuffer is "+byteBuffer);
int sampleSize=mMediaExtractor.readSampleData(byteBuffer,0);
Log.d("lpf","sampleSize is "+sampleSize);
if (sampleSize < 0){
Log.d("lpf","inputBuffer is BUFFER_FLAG_END_OF_STREAMING");
mMediaCodec.queueInputBuffer(index,0,0,0,MediaCodec.BUFFER_FLAG_END_OF_STREAM);
isEOF=true;
}else{
mMediaCodec.queueInputBuffer(index,0,sampleSize,mMediaExtractor.getSampleTime(),0);
mMediaExtractor.advance(); //下一帧数据
}
}
}
int outIndex=mMediaCodec.dequeueOutputBuffer(info,100000);
switch (outIndex){
case MediaCodec.INFO_OUTPUT_BUFFERS_CHANGED:
//当buffer变化时，必须重新指向新的buffer
outputBuffers=mMediaCodec.getOutputBuffers();
break;
case MediaCodec.INFO_OUTPUT_FORMAT_CHANGED:
//当Buffer的封装格式发生变化的时候，需重新指向新的buffer格式
Log.d("lpf","output buffer changed");
break;
case MediaCodec.INFO_TRY_AGAIN_LATER:
//dequeueOutputBuffer 超时的时候会到这个case
Log.d("lpf","dequeueOutputBuffer timeout");
break;
default:
ByteBuffer buffer=outputBuffers[outIndex];
//由于配置的时候 将Surface 传进去了 所以解码的时候 将数据直接交给了Surface进行显示了
//使用简单的时钟的方式保持视频的fps（每秒显示的帧数），不然视频会播放的比较快
Log.d("lpf","解码之后的 buffer数据="+buffer);
while (info.presentationTimeUs/1000>System.currentTimeMillis()-startMs){
try {
Thread.sleep(10);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
mMediaCodec.releaseOutputBuffer(outIndex,true);
break;
}
if ((info.flags & MediaCodec.BUFFER_FLAG_END_OF_STREAM) != 0){
Log.d("lpf","outputBuffer BUFFER_FLAG_END_OF_STREAM");
break;
}
}
mMediaCodec.stop();
mMediaCodec.release();// 释放组件
mMediaExtractor.release();
}
}
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