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• libavcodec : ffprobe on file encoded with FFV1 codec reports "read_quant_table error"

  20 novembre 2016, par Ali Alidoust

  I’m using the following code to encode a series of frames into an mkv or avi file with FFV1 encoding :

     HRESULT Session::createContext(LPCSTR filename, UINT width, UINT height, UINT fps_num, UINT fps_den) {
  
      LOG("Exporting to file: ", filename);
  
  
  
      AVCodecID codecId = AV_CODEC_ID_FFV1;
  
      this->pixelFormat = AV_PIX_FMT_YUV420P;
  
  
  
      this->codec = avcodec_find_encoder(codecId);
  
      RET_IF_NULL(this->codec, "Could not create codec", E_FAIL);
  
  
  
      this->oformat = av_guess_format(NULL, filename, NULL);
  
      RET_IF_NULL(this->oformat, "Could not create format", E_FAIL);
  
      this->oformat->video_codec = codecId;
  
      this->width = width;
  
      this->height = height;
  
      this->codecContext = avcodec_alloc_context3(this->codec);
  
      RET_IF_NULL(this->codecContext, "Could not allocate context for the codec", E_FAIL);
  
  
  
      this->codecContext->codec = this->codec;
  
      this->codecContext->codec_id = codecId;
  
  
  
      this->codecContext->pix_fmt = pixelFormat;
  
      this->codecContext->width = this->width;
  
      this->codecContext->height = this->height;
  
      this->codecContext->time_base.num = fps_den;
  
      this->codecContext->time_base.den = fps_num;
  
  
  
      this->codecContext->gop_size = 1;
  
  
  
  
  
      RET_IF_FAILED_AV(avformat_alloc_output_context2(&fmtContext, this->oformat, NULL, NULL), "Could not allocate format context", E_FAIL);
  
      RET_IF_NULL(this->fmtContext, "Could not allocate format context", E_FAIL);
  
  
  
      this->fmtContext->oformat = this->oformat;
  
      this->fmtContext->video_codec_id = codecId;
  
  
  
      this->stream = avformat_new_stream(this->fmtContext, this->codec);
  
      RET_IF_NULL(this->stream, "Could not create new stream", E_FAIL);
  
      this->stream->time_base = this->codecContext->time_base;
  
      RET_IF_FAILED_AV(avcodec_parameters_from_context(this->stream->codecpar, this->codecContext), "Could not convert AVCodecContext to AVParameters", E_FAIL);
  
  
  
      if (this->fmtContext->oformat->flags & AVFMT_GLOBALHEADER)
  
      {
  
          this->codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
      }
  
  
  
      av_opt_set_int(this->codecContext->priv_data, "coder", 0, 0);
  
      av_opt_set_int(this->codecContext->priv_data, "context", 1, 0);
  
      av_opt_set_int(this->codecContext->priv_data, "slicecrc", 1, 0);
  
      //av_opt_set_int(this->codecContext->priv_data, "slicecrc", 1, 0);
  
      //av_opt_set_int(this->codecContext->priv_data, "pix_fmt", pixelFormat, 0);
  
  
  
      RET_IF_FAILED_AV(avcodec_open2(this->codecContext, this->codec, NULL), "Could not open codec", E_FAIL);
  
      RET_IF_FAILED_AV(avio_open(&this->fmtContext->pb, filename, AVIO_FLAG_WRITE), "Could not open output file", E_FAIL);
  
      RET_IF_NULL(this->fmtContext->pb, "Could not open output file", E_FAIL);
  
      RET_IF_FAILED_AV(avformat_write_header(this->fmtContext, NULL), "Could not write header", E_FAIL);
  
  
  
      frame = av_frame_alloc();
  
      RET_IF_NULL(frame, "Could not allocate frame", E_FAIL);
  
      frame->format = this->codecContext->pix_fmt;
  
      frame->width = width;
  
      frame->height = height;
  
      return S_OK;
  
  }
  
  
  
  HRESULT Session::writeFrame(IMFSample * pSample) {
  
      IMFMediaBuffer *mediaBuffer = NULL;
  
      BYTE *pDataNV12 = NULL;
  
      DWORD length;
  
  
  
      RET_IF_FAILED(pSample->ConvertToContiguousBuffer(&mediaBuffer), "Could not convert IMFSample to contagiuous buffer", E_FAIL);
  
      RET_IF_FAILED(mediaBuffer->GetCurrentLength(&length), "Could not get buffer length", E_FAIL);
  
      RET_IF_FAILED(mediaBuffer->Lock(&pDataNV12, NULL, NULL), "Could not lock the buffer", E_FAIL);
  
      BYTE *pDataYUV420P = new BYTE[length];
  
      this->convertNV12toYUV420P(pDataNV12, pDataYUV420P, this->width, this->height);
  
      RET_IF_FAILED(av_image_fill_arrays(frame->data, frame->linesize, pDataYUV420P, pixelFormat, this->width, this->height, 1), "Could not fill the frame with data from the buffer", E_FAIL);
  
      LOG_IF_FAILED(mediaBuffer->Unlock(), "Could not unlock the buffer");
  
  
  
      frame->pts = av_rescale_q(this->pts++, this->codecContext->time_base, this->stream->time_base);
  
  
  
      AVPacket pkt;
  
  
  
      av_init_packet(&pkt);
  
      pkt.data = NULL;
  
      pkt.size = 0;
  
  
  
      RET_IF_FAILED_AV(avcodec_send_frame(this->codecContext, frame), "Could not send the frame to the encoder", E_FAIL);
  
      delete[] pDataYUV420P;
  
      if (SUCCEEDED(avcodec_receive_packet(this->codecContext, &pkt))) {
  
          RET_IF_FAILED_AV(av_interleaved_write_frame(this->fmtContext, &pkt), "Could not write the received packet.", E_FAIL);
  
      }
  
  
  
      av_packet_unref(&pkt);
  
  
  
      return S_OK;
  
  }
  
  
  
  HRESULT Session::endSession() {
  
      LOG("Ending session...");
  
  
  
      LOG("Closing files...")
  
      LOG_IF_FAILED_AV(av_write_trailer(this->fmtContext), "Could not finalize the output file.");
  
      LOG_IF_FAILED_AV(avio_close(this->fmtContext->pb), "Could not close the output file.");
  
      LOG_IF_FAILED_AV(avcodec_close(this->codecContext), "Could not close the codec.");
  
      av_free(this->codecContext);
  
      LOG("Done.")
  
      return S_OK;
  
  }

  The problem is that the generated file is not playable in either VLC or MPC-HC. However, MPC-HC reports following info in file properties :

  General
  
  Unique ID                      : 202978442142665779317960161865934977227 (0x98B439D9BE859109BD5EC00A62A238CB)
  
  Complete name                  : T:\Test.mkv
  
  Format                         : Matroska
  
  Format version                 : Version 4 / Version 2
  
  File size                      : 24.6 MiB
  
  Duration                       : 147ms
  
  Overall bit rate               : 1 401 Mbps
  
  Writing application            : Lavf57.57.100
  
  Writing library                : Lavf57.57.100
  
  
  
  Video
  
  ID                             : 1
  
  Format                         : FFV1
  
  Format version                 : Version 0
  
  Codec ID                       : V_MS/VFW/FOURCC / FFV1
  
  Duration                       : 147ms
  
  Width                          : 1 280 pixels
  
  Height                         : 720 pixels
  
  Display aspect ratio           : 16:9
  
  Frame rate mode                : Constant
  
  Frame rate                     : 1 000.000 fps
  
  Color space                    : YUV
  
  Chroma subsampling             : 4:2:0
  
  Bit depth                      : 8 bits
  
  Compression mode               : Lossless
  
  Default                        : Yes
  
  Forced                         : No
  
  DURATION                       : 00:00:00.147000000
  
  coder_type                     : Golomb Rice

  Something to note is that it reports 1000 FPS which is weird since I’ve set AVCodecContext::time_base in the code.

  UPDATE 1 :

  I managed to set the correct fps by setting time_base property of the stream :

  this->stream->time_base.den = fps_num;
  
  this->stream->time_base.num = fps_den;

  VLC plays the output file but it shows VLC logo instead of the video, as if there is no video stream in the file.

  UPDATE 2 :

  Cleaned up the code. Now if I set codecId = AV_CODEC_ID_MPEG2VIDEO the output file is valid and is played in both VLC and MPC-HC. Using ffprobe on the file with FFV1 encoding yields the following result :

  C:\root\apps\ffmpeg>ffprobe.exe t:\test.avi
  
  ffprobe version 3.2 Copyright (c) 2007-2016 the FFmpeg developers
  
    built with gcc 5.4.0 (GCC)
  
    configuration: --disable-static --enable-shared --enable-gpl --enable-version3 --disable-w32threads --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-libebur128 --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinger --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-decklink --enable-zlib
  
    libavutil      55. 34.100 / 55. 34.100
  
    libavcodec     57. 64.100 / 57. 64.100
  
    libavformat    57. 56.100 / 57. 56.100
  
    libavdevice    57.  1.100 / 57.  1.100
  
    libavfilter     6. 65.100 /  6. 65.100
  
    libswscale      4.  2.100 /  4.  2.100
  
    libswresample   2.  3.100 /  2.  3.100
  
    libpostproc    54.  1.100 / 54.  1.100
  
  [ffv1 @ 00000000006b83a0] read_quant_table error
  
  Input #0, avi, from 't:\test.avi':
  
    Metadata:
  
      encoder         : Lavf57.56.100
  
    Duration: 00:00:04.94, start: 0.000000, bitrate: 107005 kb/s
  
      Stream #0:0: Video: ffv1 (FFV1 / 0x31564646), yuv420p, 1280x720, 107717 kb/s, 29.97 fps, 29.97 tbr, 29.97 tbn, 29.97 tbc

• "opaque" pointer in ffmpeg AVFrame

  4 octobre 2016, par R2-D2

  In ffmpeg there is a structure AVFrame describing decoded video or audio data.

  It has a void pointer opaque. The documentation claims it is "for some private data of the user".

  What does this mean ?
  Can it be used to transport any additional data as per-frame metadata ?

• doc : Mention -dn in the "Stream selection" paragraph.

  27 septembre 2016, par Carl Eugen Hoyos

  doc : Mention -dn in the "Stream selection" paragraph.
  There is no "Data options" paragraph.
  
  Requested-by : ilker tezcan
  

  • [DH] doc/ffmpeg.texi