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• hevc_ps : make sure failing to decode an SPS always returns an error

  13 juillet 2015, par Anton Khirnov

  hevc_ps : make sure failing to decode an SPS always returns an error
  Some of the goto err clauses do not set the error code. It seems better
  
  to fall back on INVALIDDATA instead of adding it everywhere explicitly.
  

  • [DBH] libavcodec/hevc_ps.c

• (C) avcodec_receive_frame (ffmpeg) function always returns AVERROR(EAGAIN)

  13 avril 2021, par Levyu

  I was following this tutorial : http://dranger.com/ffmpeg/tutorial01.html
and was trying to change some deprecated functions, and so I had to try to use the avcodec_send_packet and avcodec_receive_frame functions.

  


  The problem I'm having is that avcodec_receive_frame always returns AVERROR(EAGAIN).

  


  My decoding function is as follows :

  


  static int decode(AVCodecContext *pCodecCtx, AVFrame *pFrame, AVPacket *packet) {
    
    int ret = avcodec_send_packet(pCodecCtx, packet);
    if (ret<0) {
        fprintf(stderr, "error sending packet for decoding\n");
        exit(1);
    }

    while (ret>=0) {        
        // avcodec_receive_packet(pCodecCtx, NULL);
        ret = avcodec_receive_frame(pCodecCtx, pFrame);
        if (ret == AVERROR(EAGAIN)) {
            fprintf(stderr, "\naverror(eagain) ret = %d\n", ret);
            return -1;
        }
        else if (ret == AVERROR_EOF) {
            fprintf(stderr, "eof\n");
            return -100;
        }
        else if (ret <0) {
            fprintf(stderr, "error during decoding\n");
            exit(1);
        }
    }
    return 0;
}


  


  Everywhere I read said that this is solved by calling avcodec_send_packet with the next frame, but this does not solve the problem for me because this function is being called in a loop :

  


  
    while (av_read_frame(pFormatCtx, &packet)>=0) {
        // is this a packet from the video stream?
        if (packet.stream_index==videoStream) {

           frameNotFinished = decode(pCodecCtx, pFrame, &packet);

            // did we get a video frame?
            if (!frameNotFinished) fprintf(stderr, "it worked!");
        }
        av_packet_unref(&packet);   
    }


  


  I should probably also add that avcodec_send_packet always returns 0 (success).

  


  Any help would be much appreciated.

  


• pngdec : Stop trying to decode once inflate returns Z_STREAM_END

  28 septembre 2013, par Martin Storsjö

  pngdec : Stop trying to decode once inflate returns Z_STREAM_END
  If the input buffer contains more data after the deflate stream,
  
  the loop previously left running infinitely, with inflate returning
  
  Z_STREAM_END.
  Reported-by : Mateusz "j00ru" Jurczyk and Gynvael Coldwind
  
  CC : libav-stable@libav.org
  
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavcodec/pngdec.c