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• FFmpeg - avcodec_receive_frame returns AVERROR(EAGAIN)

  8 novembre 2019, par Jinx

  I’m using an QOpenGL widget to draw frames. However, I’m struggling to get frames by using avcodec_receive_frame. It ended within the block else if (ret == AVERROR(EAGAIN)) and returned -11. I have no idea what made this happen. Also I checked that codecs were fine, so I guess the problem wasn’t caused by codecs.

  MyDemux.cpp

  AVPacket* MyDemux::allocatePacket()
  
  {
  
      AVPacket* packet = av_packet_alloc();
  
      return packet;
  
  }
  
  
  
  AVFrame* MyDemux::allocateFrame()
  
  {
  
      AVFrame* frame = av_frame_alloc();
  
      return frame;
  
  }
  
  
  
  int MyDemux::readFrame(AVPacket* packet)
  
  {
  
      mux.lock();
  
      if (!formatCtx) {
  
          std::cout << "formaetCtx is null" << std::endl;
  
          mux.unlock();
  
          return -1;
  
      }
  
      int ret = av_read_frame(formatCtx, packet);
  
      if (ret == AVERROR_EOF) {
  
          return -2;
  
      }
  
      if (ret != 0) {
  
          mux.unlock();
  
          av_packet_free(&packet);
  
          return -1;
  
      }
  
      media_type = packet->stream_index;
  
      mux.unlock();
  
      return 0;
  
  }

  MyDecode.cpp

  void MyDecode::decode(AVFrame* frame, AVPacket* packet)
  
  {
  
      int ret;
  
      ret = avcodec_send_packet(codecCtx, packet); // this returned 0
  
      while (ret == 0) {
  
          ret = avcodec_receive_frame(codecCtx, frame); // this returned -11
  
          if (ret == AVERROR(EINVAL)) {
  
              std::cout << "codec issue" << std::endl;
  
              av_frame_free(&frame);
  
              return;
  
          }
  
          else if (ret == AVERROR(EAGAIN)) { // program ends here
  
              std::cout << "output is not available this state" << std::endl;
  
              av_frame_free(&frame);
  
              return;
  
          }
  
          else if (ret == AVERROR(EINVAL)) {
  
              std::cout << "no more frames" << std::endl;
  
              av_frame_free(&frame);
  
              return;
  
          }
  
      }
  
  }

  main.cpp

  class MyThread : public QThread
  
  {
  
  public:
  
  
  
      MyDemux demux;
  
      MyDecode video_decode;
  
      myDecode audio_decode;
  
      MyVideoWidget* videoWidget;
  
      AVPacket* packet;
  
      AVFrame* frame;
  
  
  
      void initThread()
  
      {
  
          char* url = "demo.mp4";
  
          demux.openFile(url);
  
          video_decode.openCodec(demux.copy_video_codec_par());
  
          audio_decode.openCodec(demux.copy_audio_codec_par());
  
          packet = demux.allocatePacket();
  
          frame = demux.allocateFrame();
  
      }
  
      void run()
  
      {
  
          while (demux.readFrame(packet) != -2) {
  
              if (demux.get_media_type() == 0) {
  
                  video_decode.decode(frame, packet);
  
                  videoWidget->paintFrame(frame);
  
              }
  
              else if (demux.get_media_type() == 1) {
  
              }
  
          }
  
          video_decode.decode(frame, nullptr);
  
          demux.clear();
  
          demux.close();
  
      }
  
  };

• FFMPEG and Mencoder building screenshot returns 0 size images

  12 avril 2014, par Genus

  I have a script and it used to work fine but suddenly it stopped working and giving me zero size images as screenshot after video convert.

  here is the command for video screenshot.

  $cmd = $GLOBALS["paths"]["ffmpeg"]." -y -i ".$file." -f mjpeg -r 1 -ss ".$time." -vframes 1 -an ".$tmpdir."/00000001.jpg 2>&1";
  
      exec($cmd,$results);

  Debug :

  -----------------------------------------------------
  
  
  
  ------------mencoder_and_fmpeg.php SCREENSHOT -------
  
  
  
  -----------------------------------------------------
  
  
  
    COMMAND: ffmpeg -y -i /home/TESTING/public_html/vid/6d/ad/29/6dad2946a2ba102.flv -f mjpeg -r 1 -ss 14.48 -vframes 1 -an /home/TESTING/public_html/scr/42/3a/92/00000001.jpg 2>&1
  
  
  
    FFmpeg version SVN-r16244, Copyright (c) 2000-2008 Fabrice Bellard, et al.
  
  
  
    configuration: --disable-mmx --enable-shared --enable-libvorbis --enable-gpl --enable-swscale --enable-pthreads --disable-static --disable-demuxer=v4l --disable-demuxer=v4l2 --enable-libtheora --enable-gpl --enable-libspeex --enable-libmp3lame --enable-libfaac --enable-libfaad --enable-libfaadbin --enable-libamr-nb --enable-libamr-wb --enable-nonfree --enable-libxvid
  
    libavutil     49.12. 0 / 49.12. 0
  
    libavcodec    52. 7. 0 / 52.108. 0
  
    libavformat   52.23. 1 / 52.92. 0
  
    libavdevice   52. 1. 0 / 52. 2. 3
  
    libswscale     0. 6. 1 /  0.12. 0
  
  
  
    built on Apr  9 2011 22:48:41, gcc: 4.1.2 20080704 (Red Hat 4.1.2-50)
  
    built by Admin-Ahead Server Technologies FFmpeg installer v5.0.6b
  
    Seems stream 0 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 10.92 (131/12)
  
    Stream mapping:
  
    Stream #0.0 -> #0.0
  
  
  
    Press [q] to stop encoding
  
    ffmpeg: symbol lookup error: ffmpeg: undefined symbol: frame_hook_process

• How to avoid the millisecond silence that ffmpeg adds to the beginning and end of a converted mp3 ? [on hold]

  29 décembre 2015, par Von Villamor

  I’m working on a small side project regarding splicing multiple mp3 files altogether and FFMPEG has this problem where it adds a millisecond to the beginning and the end of an audio file resulting in stops in the final mixed audio. So is there a flag or workaround available to it ?

  I’m working on hundreds and hundreds of small mp3 files so editing them one by one is next to impossible.

  Here’s a sample, the splices are at 5 seconds interval.