Android MediaCodec 使用例子

Android MediaCodec 使用例子

下面的例子是使用MediaCodec 录制到文件的例子。

 1 public class AvcEncoder {  
  
private MediaCodec mediaCodec;  
private BufferedOutputStream outputStream;  
  
public AvcEncoder() {   
    File f = new File(Environment.getExternalStorageDirectory(), "Download/video_encoded.264");  
    touch (f);  
    try {  
        outputStream = new BufferedOutputStream(new FileOutputStream(f));  
        Log.i("AvcEncoder", "outputStream initialized");  
    } catch (Exception e){   
        e.printStackTrace();  
    }  
  
    mediaCodec = MediaCodec.createEncoderByType("video/avc");  
    MediaFormat mediaFormat = MediaFormat.createVideoFormat("video/avc", 320, 240);  
    mediaFormat.setInteger(MediaFormat.KEY_BIT_RATE, 125000);  
    mediaFormat.setInteger(MediaFormat.KEY_FRAME_RATE, 15);  
    mediaFormat.setInteger(MediaFormat.KEY_COLOR_FORMAT, MediaCodecInfo.CodecCapabilities.COLOR_FormatYUV420Planar);  
    mediaFormat.setInteger(MediaFormat.KEY_I_FRAME_INTERVAL, 5);  
    mediaCodec.configure(mediaFormat, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);  
    mediaCodec.start();  
}  
  
public void close() {  
    try {  
        mediaCodec.stop();  
        mediaCodec.release();  
        outputStream.flush();  
        outputStream.close();  
    } catch (Exception e){   
        e.printStackTrace();  
    }  
}  
  
// called from Camera.setPreviewCallbackWithBuffer(...) in other class  
public void offerEncoder(byte[] input) {  
    try {  
        ByteBuffer[] inputBuffers = mediaCodec.getInputBuffers();  
        ByteBuffer[] outputBuffers = mediaCodec.getOutputBuffers();  
        int inputBufferIndex = mediaCodec.dequeueInputBuffer(-1);  
        if (inputBufferIndex >= 0) {  
            ByteBuffer inputBuffer = inputBuffers[inputBufferIndex];  
            inputBuffer.clear();  
            inputBuffer.put(input);  
            mediaCodec.queueInputBuffer(inputBufferIndex, 0, input.length, 0, 0);  
        }  
  
        MediaCodec.BufferInfo bufferInfo = new MediaCodec.BufferInfo();  
        int outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo,0);  
        while (outputBufferIndex >= 0) {  
            ByteBuffer outputBuffer = outputBuffers[outputBufferIndex];  
            byte[] outData = new byte[bufferInfo.size];  
            outputBuffer.get(outData);  
            outputStream.write(outData, 0, outData.length);  
            Log.i("AvcEncoder", outData.length + " bytes written");  
  
            mediaCodec.releaseOutputBuffer(outputBufferIndex, false);  
            outputBufferIndex = mediaCodec.dequeueOutputBuffer(bufferInfo, 0);  
  
        }  
    } catch (Throwable t) {  
        t.printStackTrace();  
    }  
  
}  

这个例子配置了编码格式、视频大小、比特率、帧率等参数，然后在camera 预览的回调函数里把yuv420数据推送给mediacodec，编码后取出nalu，写入到文件。