6

我正在用 FFMpeg 解码 RTSP 视频流。在显示时（调用cv::imshow(...)），我得到以下异常：

[swscaler @ 0d55e5c0] 使用了不推荐使用的像素格式，请确保您正确设置了范围

我正在将像素格式从“AV_PIX_FMT_YUVJ420P”转换为“AV_PIX_FMT_YUV420P”。仍然得到上述异常。任何帮助表示赞赏；

int Decodestream()
{
    av_register_all();
    avdevice_register_all();
    avcodec_register_all();
    avformat_network_init();

    const char  *filenameSrc = "rtsp://192.168.1.67/gnz_media/second";

    AVCodecContext  *pCodecCtx;
    AVFormatContext *pFormatCtx = avformat_alloc_context();

    AVCodec * pCodec;
    AVFrame *pFrame, *pFrameRGB;

    if(avformat_open_input(&pFormatCtx,filenameSrc,NULL,NULL) != 0)
    {return -1;}

    if(av_find_stream_info(pFormatCtx) < 0)   
    {return -1;}

    av_dump_format(pFormatCtx, 0, filenameSrc, 0);

    int videoStream = 1;

    for(int i=0; i < pFormatCtx->nb_streams; i++)
    {
        if(pFormatCtx->streams[i]->codec->coder_type==AVMEDIA_TYPE_VIDEO)
        {
            videoStream = i;
            break;
        }
    }

    if(videoStream == -1) return -1 ;

    pCodecCtx = pFormatCtx->streams[videoStream]->codec;

    pCodec =avcodec_find_decoder(pCodecCtx->codec_id);

    if(pCodec==NULL)
    {return -1;} //codec not found

    if(avcodec_open2(pCodecCtx,pCodec,NULL) < 0)
    { return -1;}

    pFrame    = avcodec_alloc_frame();
    pFrameRGB = avcodec_alloc_frame();

    uint8_t *buffer;

    int numBytes;

    AVPixelFormat  pFormat;

    switch (pFormatCtx->streams[videoStream]->codec->pix_fmt) 
    {
    case AV_PIX_FMT_YUVJ420P : pFormat = AV_PIX_FMT_YUV420P; break;
    case AV_PIX_FMT_YUVJ422P : pFormat = AV_PIX_FMT_YUV422P; break;
    case AV_PIX_FMT_YUVJ444P : pFormat = AV_PIX_FMT_YUV444P; break;
    case AV_PIX_FMT_YUVJ440P : pFormat = AV_PIX_FMT_YUV440P; 
    default:
        pFormat = pFormatCtx->streams[videoStream]->codec->pix_fmt;
        break;
    }

    numBytes = avpicture_get_size(pFormat,pCodecCtx->width,pCodecCtx->height) ; 

    buffer = (uint8_t *) av_malloc(numBytes*sizeof(uint8_t));

    avpicture_fill((AVPicture *) pFrameRGB,buffer,pFormat,pCodecCtx->width,pCodecCtx->height);

    int res, frameFinished;

    AVPacket packet;

    while(res = av_read_frame(pFormatCtx,&packet)>=0)
    {

        if(packet.stream_index == videoStream){

            avcodec_decode_video2(pCodecCtx,pFrame,&frameFinished,&packet);

            if(frameFinished){

                struct SwsContext * img_convert_ctx;

                img_convert_ctx = sws_getCachedContext(NULL,pCodecCtx->width, pCodecCtx->height, pCodecCtx->pix_fmt,   pCodecCtx->width, pCodecCtx->height, AV_PIX_FMT_BGR24, SWS_BICUBIC, NULL, NULL,NULL);

                sws_scale(img_convert_ctx, ((AVPicture*)pFrame)->data, ((AVPicture*)pFrame)->linesize, 0, pCodecCtx->height, ((AVPicture *)pFrameRGB)->data, ((AVPicture *)pFrameRGB)->linesize);

                cv::Mat img(pFrame->height,pFrame->width,CV_8UC3,pFrameRGB->data[0]);
                cv::imshow("display",img);
                cvWaitKey(10);          
            }
        }

    }
    //Memory clean up code goes here 
}
4

0 回答 0