FFmpegh.264解碼

- (int)DecodeH264Frames: (unsigned char*)inputBuffer withLength:(int)aLength
{
    int gotPicPtr=0;
    int result=0;
    
    av_init_packet(&pAvPackage);
    pAvPackage.data=(unsigned char*)inputBuffer;
    pAvPackage.size=aLength;
    //解碼
    result=avcodec_decode_video2(pCodecCtx, pVideoFrame, &gotPicPtr, &pAvPackage);
    
    //若是視頻尺寸更改，咱們丟掉這個frame
    if((pictureWidth!=0)&&(pictureWidth!=pCodecCtx->width)){
        setRecordResolveState=0;
        pictureWidth=pCodecCtx->width;
        return -1;
    }

    //YUV 420 Y U V  -> RGB
    if(gotPicPtr)
    {

        unsigned int lumaLength= (pCodecCtx->height)*(MIN(pVideoFrame->linesize[0], pCodecCtx->width));// W * H
        unsigned int chromBLength=((pCodecCtx->height)/2)*(MIN(pVideoFrame->linesize[1], (pCodecCtx->width)/2));// w * h/4
        unsigned int chromRLength=((pCodecCtx->height)/2)*(MIN(pVideoFrame->linesize[2], (pCodecCtx->width)/2));
        
        H264YUV_Frame    yuvFrame;
        memset(&yuvFrame, 0, sizeof(H264YUV_Frame));
        
        yuvFrame.luma.length = lumaLength;
        yuvFrame.chromaB.length = chromBLength;
        yuvFrame.chromaR.length =chromRLength;
        yuvFrame.luma.dataBuffer=(unsigned char*)malloc(lumaLength);
        yuvFrame.chromaB.dataBuffer=(unsigned char*)malloc(chromBLength);
        yuvFrame.chromaR.dataBuffer=(unsigned char*)malloc(chromRLength);
        copyDecodedFrame(pVideoFrame->data[0],yuvFrame.luma.dataBuffer,pVideoFrame->linesize[0],
                         pCodecCtx->width,pCodecCtx->height);
        copyDecodedFrame(pVideoFrame->data[1], yuvFrame.chromaB.dataBuffer,pVideoFrame->linesize[1],
                         pCodecCtx->width / 2,pCodecCtx->height / 2);
        copyDecodedFrame(pVideoFrame->data[2], yuvFrame.chromaR.dataBuffer,pVideoFrame->linesize[2],
                         pCodecCtx->width / 2,pCodecCtx->height / 2);
        
        yuvFrame.width=pCodecCtx->width;
        yuvFrame.height=pCodecCtx->height;


        dispatch_sync(dispatch_get_main_queue(), ^{
            
            [self updateYUVFrameOnMainThread:(H264YUV_Frame*)&yuvFrame];
        });
        
        free(yuvFrame.luma.dataBuffer);
        free(yuvFrame.chromaB.dataBuffer);
        free(yuvFrame.chromaR.dataBuffer);
        
    }
    av_free_packet(&pAvPackage);
    
    return 0;
}