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• ffmpeg command failed

  25 octobre 2015, par Asad kamran

  I am experimenting FFMPEG command to convert any video format to mp4.

  Server admin execute the below command created by me and show me the errors :

  ffmpeg -ss 00:03:00  -i  /video/1444107854.mov -c:v libx264 /video/player/1444107854.mp4  -vframes 1 /video/thumb/1444107854.jpg

  This is error :

  [aac @ 0x2b845a0] The encoder ’aac’ is experimental but experimental
  codecs are not enabled, add ’-strict -2’ if you want to use it.

  how can i avoid this error and also experimental codec, so can any one let me know what can be best codec if i explicitly specify it.

  my ffmpeg and server are as follow :

  ffmpeg version N-75903-g14573b9 Copyright (c) 2000-2015 the FFmpeg
  developers built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16)

  EDIT 1 :
  I change the command a bit and add -c:a copy to copy audio stream as it is but still no hope :

  New command :

  ffmpeg -ss 00:03:00  -i  /video/1444107854.mov -c:v libx264 -c:a copy /video/player/1444107854.mp4  -vframes 1 /video/thumb/1444107854.jpg

  After executing this i got a file of 23k size, apparently as in log it only copy audio stream and no video is added in final output.
  Its Log is as follow :

  > ffmpeg version N-75903-g14573b9 Copyright (c) 2000-2015 the FFmpeg
  
  > developers   built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16)  
  
  > configuration: --enable-libx264 --enable-gpl   libavutil      55. 
  
  > 3.100 / 55.  3.100   libavcodec     57.  5.100 / 57.  5.100   libavformat    57.  3.100 / 57.  3.100   libavdevice    57.  0.100 /
  
  > 57.  0.100   libavfilter     6. 10.100 /  6. 10.100   libswscale      4.  0.100 /  4.  0.100   libswresample   2.  0.100 /  2.  0.100   libpostproc    54.  0.100 / 54.  0.100 Input #0, mpeg, from
  
  > '/video/1444108714.mpg':  
  
  > Duration: 00:00:02.14, start: 0.184278, bitrate: 15689 kb/s
  
  >     Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], max. 38810 kb/s, 29.97 fps, 29.97 tbr,
  
  > 90k tbn, 59.94 tbc
  
  >     Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), fltp, 448 kb/s [swscaler @ 0x347fda0] deprecated pixel format used, make sure you did
  
  > set range correctly [libx264 @ 0x34708a0] using SAR=1/1 [libx264 @
  
  > 0x34708a0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 [libx264
  
  > @ 0x34708a0] profile High, level 4.0 [libx264 @ 0x34708a0] 264 - core
  
  > 148 r2597 e86f3a1 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 -
  
  > http://www.videolan.org/x264.html - options: cabac=1 ref=3
  
  > deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00
  
  > mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0
  
  > deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=34
  
  > lookahead_threads=5 sliced_threads=0 nr=0 decimate=1 interlaced=0
  
  > bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1
  
  > b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250
  
  > keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf
  
  > mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40
  
  > aq=1:1.00 [mp4 @ 0x346f6c0] Codec for stream 1 does not use global
  
  > headers but container format requires global headers [mp4 @ 0x346f6c0]
  
  > track 1: codec frame size is not set Output #0, mp4, to
  
  > '/video/player/1444108714.mp4':  
  
  > Metadata:
  
  >     encoder         : Lavf57.3.100
  
  >     Stream #0:0: Video: h264 (libx264) ([33][0][0][0] / 0x0021), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], q=-1--1, 29.97 fps, 30k tbn,
  
  > 29.97 tbc
  
  >     Metadata:
  
  >       encoder         : Lavc57.5.100 libx264
  
  >     Stream #0:1: Audio: ac3 ([165][0][0][0] / 0x00A5), 48000 Hz, 5.1(side), 448 kb/s Output #1, image2, to '/video/thumb/1444108714.jpg':  
  
  > Metadata:
  
  >     encoder         : Lavf57.3.100
  
  >     Stream #1:0: Video: mjpeg, yuvj420p(pc), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 29.97 fps, 29.97 tbn, 29.97 tbc
  
  >     Metadata:
  
  >       encoder         : Lavc57.5.100 mjpeg Stream mapping:   Stream #0:0 -> #0:0 (mpeg2video (native) -> h264 (libx264))   Stream #0:1 -> #0:1 (copy)   Stream #0:0 -> #1:0 (mpeg2video (native) -> mjpeg (native)) Press [q] to stop, [?] for help [mp4 @ 0x346f6c0]
  
  > Non-monotonous DTS in output stream 0:1; previous: 2208, current: 672;
  
  > changing to 2209. This may result in incorrect timestamps in the
  
  > output file. frame=    0 fps=0.0 q=0.0 Lq=0.0 size=      23kB
  
  > time=00:00:00.07 bitrate=2447.5kbits/s video:0kB audio:23kB
  
  > subtitle:0kB other streams:0kB global headers:0kB muxing overhead:
  
  > 3.457839%

  EDIT 2 :

  ffmpeg -y -i ./1445675270.m4b -c:v libx264  -crf 20 -preset slow -pix_fmt yuv420p -movflags +faststart -c:a libfdk_aac -b:a 128k  ./player/1445675270.mp4 -vframes 1 ./thumb/1445675270.jpg

  Above command output the below message, i will appreciate if you can suggest.

  ffmpeg version git-2015-10-11-49f4967 Copyright (c) 2000-2015 the FFmpeg developers
  
    built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-16)
  
    configuration: --prefix=/root/ffmpeg_build --extra-cflags=-I/root/ffmpeg_build/include --extra-ldflags=-L/root/ffmpeg_build/lib --bindir=/root/bin --pkg-config-flags=--static --enable-gpl --enable-nonfree --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libx265
  
    libavutil      55.  3.100 / 55.  3.100
  
    libavcodec     57.  5.100 / 57.  5.100
  
    libavformat    57.  3.100 / 57.  3.100
  
    libavdevice    57.  0.100 / 57.  0.100
  
    libavfilter     6. 11.100 /  6. 11.100
  
    libswscale      4.  0.100 /  4.  0.100
  
    libswresample   2.  0.100 /  2.  0.100
  
    libpostproc    54.  0.100 / 54.  0.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x31e07c0] stream 0, timescale not set
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from './1445675270.m4b':
  
    Metadata:
  
      major_brand     : M4A 
  
      minor_version   : 0
  
      compatible_brands: M4A mp42isom
  
      creation_time   : 2005-08-01 07:26:16
  
      tool            : ?
  
      title           : MAKE_2005-08-01
  
      artist          : MAKE Magazine
  
      composer        : MAKE Magazine - Phillip Torrone
  
      album           : Interview with Janus Wireless
  
      grouping        : MAKE Magazine enhanced podcast
  
      genre           : Podcast
  
      date            : 2005
  
      comment         : Interview with Janus wireless and their 5 Wi-Fi card packet capturing Linux box. This is a special enhanced podcast (this file plays images and links in iTunes and on iPod color devices).
  
    Duration: 00:02:57.54, start: 0.000000, bitrate: 162 kb/s
  
      Chapter #0:0: start 0.000000, end 17.000000
  
      Metadata:
  
        title           : MAKE Magazine @ DEFCON with JANUS
  
      Chapter #0:1: start 17.000000, end 37.000000
  
      Metadata:
  
        title           : Janus
  
      Chapter #0:2: start 37.000000, end 83.000000
  
      Metadata:
  
        title           : Construction
  
      Chapter #0:3: start 83.000000, end 109.000000
  
      Metadata:
  
        title           : The MAKERs
  
      Chapter #0:4: start 109.000000, end 177.540000
  
      Metadata:
  
        title           : Display
  
      Stream #0:0(eng): Audio: aac (LC) (mp4a / 0x6134706D), 22050 Hz, mono, fltp, 32 kb/s (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
      Stream #0:1(eng): Subtitle: mov_text (text / 0x74786574), 0 kb/s
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
      Stream #0:2(eng): Video: tiff (tiff / 0x66666974), rgb24, 167x166, 126 kb/s, SAR 206:275 DAR 17201:22825, 0.03 fps, 1 tbr, 22050 tbn, 22050 tbc (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
        encoder         : TIFF (Uncompressed)
  
      Stream #0:3(eng): Subtitle: mov_text (tx3g / 0x67337874), 160x160, 0 kb/s (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
      Stream #0:4: Video: mjpeg, yuvj444p(pc, bt470bg/unknown/unknown), 167x166 [SAR 1:1 DAR 167:166], 90k tbr, 90k tbn, 90k tbc
  
  [swscaler @ 0x3242360] deprecated pixel format used, make sure you did set range correctly
  
  [libx264 @ 0x3228c40] width not divisible by 2 (167x166)
  
  Output #0, mp4, to './player/1445675270.mp4':
  
    Metadata:
  
      major_brand     : M4A 
  
      minor_version   : 0
  
      compatible_brands: M4A mp42isom
  
      comment         : Interview with Janus wireless and their 5 Wi-Fi card packet capturing Linux box. This is a special enhanced podcast (this file plays images and links in iTunes and on iPod color devices).
  
      tool            : ?
  
      title           : MAKE_2005-08-01
  
      artist          : MAKE Magazine
  
      composer        : MAKE Magazine - Phillip Torrone
  
      album           : Interview with Janus Wireless
  
      grouping        : MAKE Magazine enhanced podcast
  
      genre           : Podcast
  
      date            : 2005
  
      Chapter #0:0: start 0.000000, end 17.000000
  
      Metadata:
  
        title           : MAKE Magazine @ DEFCON with JANUS
  
      Chapter #0:1: start 17.000000, end 37.000000
  
      Metadata:
  
        title           : Janus
  
      Chapter #0:2: start 37.000000, end 83.000000
  
      Metadata:
  
        title           : Construction
  
      Chapter #0:3: start 83.000000, end 109.000000
  
      Metadata:
  
        title           : The MAKERs
  
      Chapter #0:4: start 109.000000, end 177.540000
  
      Metadata:
  
        title           : Display
  
      Stream #0:0(eng): Video: h264, none, q=2-31, 128 kb/s, SAR 206:275 DAR 0:0, 1 fps (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
        encoder         : Lavc57.5.100 libx264
  
      Stream #0:1(eng): Audio: aac, 0 channels, 128 kb/s (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
        encoder         : Lavc57.5.100 libfdk_aac
  
  Output #1, image2, to './thumb/1445675270.jpg':
  
    Metadata:
  
      major_brand     : M4A 
  
      minor_version   : 0
  
      compatible_brands: M4A mp42isom
  
      comment         : Interview with Janus wireless and their 5 Wi-Fi card packet capturing Linux box. This is a special enhanced podcast (this file plays images and links in iTunes and on iPod color devices).
  
      tool            : ?
  
      title           : MAKE_2005-08-01
  
      artist          : MAKE Magazine
  
      composer        : MAKE Magazine - Phillip Torrone
  
      album           : Interview with Janus Wireless
  
      grouping        : MAKE Magazine enhanced podcast
  
      genre           : Podcast
  
      date            : 2005
  
      Chapter #1:0: start 0.000000, end 17.000000
  
      Metadata:
  
        title           : MAKE Magazine @ DEFCON with JANUS
  
      Chapter #1:1: start 17.000000, end 37.000000
  
      Metadata:
  
        title           : Janus
  
      Chapter #1:2: start 37.000000, end 83.000000
  
      Metadata:
  
        title           : Construction
  
      Chapter #1:3: start 83.000000, end 109.000000
  
      Metadata:
  
        title           : The MAKERs
  
      Chapter #1:4: start 109.000000, end 177.540000
  
      Metadata:
  
        title           : Display
  
      Stream #1:0(eng): Video: mjpeg, none, q=2-31, 128 kb/s, SAR 206:275 DAR 0:0, 1 fps (default)
  
      Metadata:
  
        creation_time   : 2005-08-01 07:26:16
  
        handler_name    : ?Apple Alias Data Handler
  
        encoder         : Lavc57.5.100 mjpeg
  
  Stream mapping:
  
    Stream #0:2 -> #0:0 (tiff (native) -> h264 (libx264))
  
    Stream #0:0 -> #0:1 (aac (native) -> aac (libfdk_aac))
  
    Stream #0:2 -> #1:0 (tiff (native) -> mjpeg (native))
  
  Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

• Random segmentation fault with avcodec_encode_video2()

  10 août 2015, par Seba Arriagada

  this is my first question so i hope i did it correctly. If not, please let me know to fix it.

  I’m trying to convert a short (10 secs) mp4 video file into a gif using ffmpeg libraries (I’m pretty new using ffmpeg). The program works pretty well converting to gif, but some times it randomly crash.

  This is the version of the ffmpeg libraries I’m using :

  libavutil      54. 27.100
  
  libavcodec     56. 41.100
  
  libavformat    56. 36.100
  
  libavdevice    56.  4.100
  
  libavfilter     5. 16.101
  
  libavresample   2.  1.  0
  
  libswscale      3.  1.101
  
  libswresample   1.  2.100
  
  libpostproc    53.  3.100

  I’m using a 1920x1080p video, so in order to generate the gif I’m doing a pixel format convertion, from AV_PIX_FMT_YUV420P to AV_PIX_FMT_RGB8 with a resizing from the initial resolution to 432x240p.

  Here is the code :

  int VideoManager::loadVideo(QString filename, bool showInfo)
  
  {
  
      if(avformat_open_input(&iFmtCtx, filename.toStdString().c_str(), 0, 0) < 0)
  
      {
  
          qDebug() << "Could not open input file " << filename;
  
          closeInput();
  
          return -1;
  
      }
  
      if (avformat_find_stream_info(iFmtCtx, 0) < 0)
  
      {
  
          qDebug() << "Failed to retrieve input stream information";
  
          closeInput();
  
          return -2;
  
      }
  
  
  
      videoStreamIndex = -1;
  
      for(unsigned int i = 0; i < iFmtCtx->nb_streams; ++i)
  
          if(iFmtCtx->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO)
  
          {
  
              videoStreamIndex = i;
  
              break;
  
          }
  
  
  
      if(videoStreamIndex == -1)
  
      {
  
          qDebug() << "Didn't find any video stream!";
  
          closeInput();
  
          return -3;
  
      }
  
      iCodecCtx = iFmtCtx->streams[videoStreamIndex]->codec;
  
  
  
      iCodec = avcodec_find_decoder(iCodecCtx->codec_id);
  
      if(iCodec == NULL) // Codec not found
  
      {
  
          qDebug() << "Codec not found!";
  
          closeInput();
  
          return -4;
  
      }
  
      if(avcodec_open2(iCodecCtx, iCodec, NULL) < 0)
  
      {
  
          qDebug() << "Could not open codec!";
  
          closeInput();
  
          return -1;
  
      }
  
  
  
      if(showInfo)
  
          av_dump_format(iFmtCtx, 0, filename.toStdString().c_str(), 0);
  
  
  
      return 0;
  
  }
  
  
  
  void VideoManager::generateGif(QString filename)
  
  {
  
      int ret, frameCount = 0;
  
      AVPacket packet;
  
      packet.data = NULL;
  
      packet.size = 0;
  
      AVFrame *frame = NULL;
  
      unsigned int stream_index;
  
      int got_frame;
  
  
  
      gifHeight = iFmtCtx->streams[videoStreamIndex]->codec->height;
  
      gifWidth  = iFmtCtx->streams[videoStreamIndex]->codec->width;
  
  
  
      if(gifHeight > MAX_GIF_HEIGHT || gifWidth > MAX_GIF_WIDTH)
  
      {
  
          if(gifHeight > gifWidth)
  
          {
  
              gifWidth  = (float)gifWidth * ( (float)MAX_GIF_HEIGHT / (float)gifHeight );
  
              gifHeight = MAX_GIF_HEIGHT;
  
          }
  
          else
  
          {
  
              gifHeight = (float)gifHeight * ( (float)MAX_GIF_WIDTH / (float)gifWidth );
  
              gifWidth  = MAX_GIF_WIDTH;
  
          }
  
      }
  
  
  
  
  
      if(openOutputFile(filename.toStdString().c_str()) < 0)
  
      {
  
          qDebug() << "Error openning output file: " << filename;
  
          return;
  
      }
  
  
  
      while (1) {
  
          int ret = av_read_frame(iFmtCtx, &packet);
  
          if (ret < 0)
  
          {
  
              if(ret != AVERROR_EOF)
  
                  qDebug() << "Error reading frame: " << ret;
  
              break;
  
          }
  
          stream_index = packet.stream_index;
  
  
  
          if(stream_index == videoStreamIndex)
  
          {
  
              frame = av_frame_alloc();
  
              if (!frame) {
  
                  qDebug() << "Error allocating frame";
  
                  break;
  
              }
  
              av_packet_rescale_ts(&packet,
  
                                   iFmtCtx->streams[stream_index]->time_base,
  
                                   iFmtCtx->streams[stream_index]->codec->time_base);
  
  
  
              ret = avcodec_decode_video2(iFmtCtx->streams[stream_index]->codec, frame,
  
                      &got_frame, &packet);
  
              if (ret < 0) {
  
                  qDebug() << "Decoding failed";
  
                  break;
  
              }
  
  
  
              if(got_frame)
  
              {
  
                  qDebug() << ++frameCount;
  
                  nframes++;
  
                  frame->pts = av_frame_get_best_effort_timestamp(frame);
  
  
  
                  ////////////////////////////////////////////////////////////////////////////////
  
                  /// Pixel format convertion and resize
  
                  ////////////////////////////////////////////////////////////////////////////////
  
                  uint8_t *out_buffer = NULL;
  
                  SwsContext *img_convert_ctx = NULL;
  
                  AVFrame *pFrameRGB = av_frame_alloc();
  
  
  
                  if(pFrameRGB == NULL)
  
                  {
  
                      qDebug() << "Error allocating frameRGB";
  
                      break;
  
                  }
  
  
  
                  AVPixelFormat pixFmt;
  
                  switch (iFmtCtx->streams[stream_index]->codec->pix_fmt)
  
                  {
  
                  case AV_PIX_FMT_YUVJ420P : pixFmt = AV_PIX_FMT_YUV420P; break;
  
                  case AV_PIX_FMT_YUVJ422P : pixFmt = AV_PIX_FMT_YUV422P; break;
  
                  case AV_PIX_FMT_YUVJ444P : pixFmt = AV_PIX_FMT_YUV444P; break;
  
                  case AV_PIX_FMT_YUVJ440P : pixFmt = AV_PIX_FMT_YUV440P; break;
  
                  default:
  
                      pixFmt = iFmtCtx->streams[stream_index]->codec->pix_fmt;
  
                  }
  
  
  
                  out_buffer = (uint8_t*)av_malloc( avpicture_get_size( AV_PIX_FMT_RGB8,
  
                                                    gifWidth,
  
                                                    gifHeight ));
  
                  if(!out_buffer)
  
                  {
  
                      qDebug() << "Error alocatting out_buffer!";
  
                  }
  
                  avpicture_fill((AVPicture *)pFrameRGB, out_buffer, AV_PIX_FMT_RGB8,
  
                                 gifWidth,
  
                                 gifHeight);
  
                  img_convert_ctx = sws_getContext( iFmtCtx->streams[stream_index]->codec->width,
  
                                                    iFmtCtx->streams[stream_index]->codec->height,
  
                                                    pixFmt,
  
                                                    gifWidth,
  
                                                    gifHeight,
  
                                                    AV_PIX_FMT_RGB8,
  
                                                    SWS_ERROR_DIFFUSION, NULL, NULL, NULL );
  
  
  
                  if(!img_convert_ctx)
  
                  {
  
                      qDebug() << "error getting sws context";
  
                  }
  
  
  
                  sws_scale( img_convert_ctx, (const uint8_t* const*)frame->data,
  
                             frame->linesize, 0,
  
                             iFmtCtx->streams[stream_index]->codec->height,
  
                             pFrameRGB->data,
  
                             pFrameRGB->linesize );
  
  
  
                  pFrameRGB->format = AV_PIX_FMT_RGB8;
  
                  pFrameRGB->pts = frame->pts;
  
                  pFrameRGB->best_effort_timestamp = frame->best_effort_timestamp;
  
                  pFrameRGB->width = gifWidth;
  
                  pFrameRGB->height = gifHeight;
  
                  pFrameRGB->pkt_dts = frame->pkt_dts;
  
                  pFrameRGB->pkt_pts = frame->pkt_pts;
  
                  pFrameRGB->pkt_duration = frame->pkt_duration;
  
                  pFrameRGB->pkt_pos = frame->pkt_pos;
  
                  pFrameRGB->pkt_size = frame->pkt_size;
  
                  pFrameRGB->interlaced_frame = frame->interlaced_frame;
  
                  ////////////////////////////////////////////////////////////////////////////////
  
                  ret = encodeAndWriteFrame(pFrameRGB, stream_index, NULL);
  
                  //av_frame_free(&frame);
  
                  //av_free(out_buffer);
  
                  //sws_freeContext(img_convert_ctx);
  
                  if (ret < 0)
  
                  {
  
                      qDebug() << "Error encoding and writting frame";
  
                      //av_free_packet(&packet);
  
                      closeOutput();
  
                  }
  
              } 
  
              else {
  
                  //av_frame_free(&frame);
  
              }
  
          }
  
          av_free_packet(&packet);
  
      }
  
  
  
      ret = flushEncoder(videoStreamIndex);
  
      if (ret < 0)
  
      {
  
          qDebug() << "Flushing encoder failed";
  
      }
  
  
  
      av_write_trailer(oFmtCtx);
  
  
  
      //av_free_packet(&packet);
  
      //av_frame_free(&frame);
  
      closeOutput();
  
  }
  
  
  
  
  
  void VideoManager::closeOutput()
  
  {
  
      if (oFmtCtx && oFmtCtx->nb_streams > 0 && oFmtCtx->streams[0] && oFmtCtx->streams[0]->codec)
  
          avcodec_close(oFmtCtx->streams[0]->codec);
  
      if (oFmtCtx && oFmt && !(oFmt->flags & AVFMT_NOFILE))
  
          avio_closep(&oFmtCtx->pb);
  
      avformat_free_context(oFmtCtx);
  
  }
  
  
  
  int VideoManager::openOutputFile(const char *filename)
  
  {
  
      AVStream *out_stream;
  
      AVStream *in_stream;
  
      AVCodecContext *dec_ctx, *enc_ctx;
  
      AVCodec *encoder;
  
      int ret;
  
  
  
      oFmtCtx = NULL;
  
      avformat_alloc_output_context2(&oFmtCtx, NULL, NULL, filename);
  
      if (!oFmtCtx) {
  
          qDebug() << "Could not create output context";
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
      oFmt = oFmtCtx->oformat;
  
  
  
      out_stream = avformat_new_stream(oFmtCtx, NULL);
  
      if (!out_stream) {
  
          qDebug() << "Failed allocating output stream";
  
          return AVERROR_UNKNOWN;
  
      }
  
  
  
      in_stream = iFmtCtx->streams[videoStreamIndex];
  
      dec_ctx = in_stream->codec;
  
      enc_ctx = out_stream->codec;
  
  
  
      encoder = avcodec_find_encoder(AV_CODEC_ID_GIF);
  
      if (!encoder) {
  
          qDebug() << "FATAL!: Necessary encoder not found";
  
          return AVERROR_INVALIDDATA;
  
      }
  
  
  
      enc_ctx->height = gifHeight;    
  
      enc_ctx->width = gifWidth;      
  
      enc_ctx->sample_aspect_ratio = dec_ctx->sample_aspect_ratio;
  
      enc_ctx->pix_fmt = AV_PIX_FMT_RGB8;
  
      enc_ctx->time_base = dec_ctx->time_base;
  
      ret = avcodec_open2(enc_ctx, encoder, NULL);
  
      if (ret < 0) {
  
          qDebug() << "Cannot open video encoder for gif";
  
          return ret;
  
      }
  
  
  
      if (oFmt->flags & AVFMT_GLOBALHEADER)
  
          enc_ctx->flags |= CODEC_FLAG_GLOBAL_HEADER;
  
  
  
      if (!(oFmt->flags & AVFMT_NOFILE)) {
  
          ret = avio_open(&oFmtCtx->pb, filename, AVIO_FLAG_WRITE);
  
          if (ret < 0) {
  
              qDebug() << "Could not open output file " << filename;
  
              return ret;
  
          }
  
      }
  
  
  
      ret = avformat_write_header(oFmtCtx, NULL);
  
      if (ret < 0) {
  
          qDebug() << "Error occurred when opening output file";
  
          return ret;
  
      }
  
  
  
      return 0;
  
  }
  
  
  
  
  
  int VideoManager::encodeAndWriteFrame(AVFrame *frame, unsigned int stream_index, int *got_frame) {
  
      int ret;
  
      int got_frame_local;
  
      AVPacket enc_pkt;
  
  
  
      if (!got_frame)
  
          got_frame = &got_frame_local;
  
  
  
      enc_pkt.data = NULL;
  
      enc_pkt.size = 0;
  
      av_init_packet(&enc_pkt);
  
      ret = avcodec_encode_video2(oFmtCtx->streams[stream_index]->codec, &enc_pkt,
  
              frame, got_frame);
  
      //av_frame_free(&frame);
  
      if (ret < 0)
  
          return ret;
  
      if (!(*got_frame))
  
          return 0;
  
  
  
      enc_pkt.stream_index = stream_index;
  
      av_packet_rescale_ts(&enc_pkt,
  
                           oFmtCtx->streams[stream_index]->codec->time_base,
  
                           oFmtCtx->streams[stream_index]->time_base);
  
  
  
      ret = av_interleaved_write_frame(oFmtCtx, &enc_pkt);
  
      return ret;
  
  }
  
  
  
  
  
  int VideoManager::flushEncoder(unsigned int stream_index)
  
  {
  
      int ret;
  
      int got_frame;
  
  
  
      if (!(oFmtCtx->streams[stream_index]->codec->codec->capabilities &
  
                  CODEC_CAP_DELAY))
  
          return 0;
  
  
  
      while (1) {
  
          ret = encodeAndWriteFrame(NULL, stream_index, &got_frame);
  
          if (ret < 0)
  
              break;
  
          if (!got_frame)
  
              return 0;
  
      }
  
      return ret;
  
  }

  I know there are a lot of memory leaks. I deleted/commented most of the free functions intentionality because i thought that was the problem.

  I’m using Qtcreator, so when i debug the programs this is the output :

  Level Function                            Line
  
  0     av_image_copy                       303
  
  1     frame_copy_video                    650     
  
  2     av_frame_copy                       687     
  
  3     av_frame_ref                        384     
  
  4     gif_encode_frame                    307     
  
  5     avcodec_encode_video2               2191     
  
  6     VideoManager::encodeAndWriteFrame   813     
  
  7     VideoManager::generateGif           375     
  
  8     qMain                               31     
  
  9     WinMain*16                          112     
  
  10    main

  I’ve checked if there is a specific frame the program crash at, but it’s a random frame too.

  Any idea of what i’m doing wrong ? Any help would be very appreciated.

  EDIT :

  After a few days of pain, suffering and frustation I decided to write the whole code from scratch. Both times i started from this example and modified it in order to works as I described before. And it works perfectly now :D ! The only error i could find in the old code (posted before) is when i try to access to the video stream in the output file I used videoStreamIndex, but that index is from the video stream in the input file. Some times it could be the same index and some times not. But it doesn’t explain why it crashed randomly. If that was the reason of the crash, it should crash every time i ran the code with the same video. So probably, there are more errors in that code.
  Notice that i’ve not tested if fixing that error in the code above actually solve the crashing problems.

• What is “interoperable TTML” ?

  19 septembre 2012, par silvia

  I’ve just tried to come to terms with the latest state of TTML, the Timed Text Markup Language.

  TTML has been specified by the W3C Timed Text Working Group and released as a RECommendation v1.0 in November 2010. Since then, several organisations have tried to adopt it as their caption file format. This includes the SMPTE, the EBU (European Broadcasting Union), and Microsoft.

  Both, Microsoft and the EBU actually looked at TTML in detail and decided that in order to make it usable for their use cases, a restriction of its functionalities is needed.

  EBU-TT

  The EBU released EBU-TT, which restricts the set of valid attributes and feature. “The EBU-TT format is intended to constrain the features provided by TTML, especially to make EBU-TT more suitable for the use with broadcast video and web video applications.” (see EBU-TT).

  In addition, EBU-specific namespaces were introduce to extend TTML with EBU-specific data types, e.g. ebuttdt:frameRateMultiplierType or ebuttdt:smpteTimingType. Similarly, a bunch of metadata elements were introduced, e.g. ebuttm:documentMetadata, ebuttm:documentEbuttVersion, or ebuttm:documentIdentifier.

  The use of namespaces as an extensibility mechanism will ascertain that EBU-TT files continue to be valid TTML files. However, any vanilla TTML parser will not know what to do with these custom extensions and will drop them on the floor.

  Simple Delivery Profile

  With the intention to make TTML ready for “internet delivery of Captions originated in the United States”, Microsoft proposed a “Simple Delivery Profile for Closed Captions (US)” (see Simple Profile). The Simple Profile is also a restriction of TTML.

  Unfortunately, the Microsoft profile is not the same as the EBU-TT profile : for example, it contains the “set” element, which is not conformant in EBU-TT. Similarly, the supported style features are different, e.g. Simple Profile supports “display-region”, while EBU-TT does not. On the other hand, EBU-TT supports monospace, sans-serif and serif fonts, while the Simple profile does not.

  Thus files created for the Simple Delivery Profile will not work on players that expect EBU-TT and the reverse.

  Fortunately, the Simple Delivery Profile does not introduce any new namespaces and new features, so at least it is an explicit subpart of TTML and not both a restriction and extension like EBU-TT.

  SMPTE-TT

  SMPTE also created a version of the TTML standard called SMPTE-TT. SMPTE did not decide on a subset of TTML for their purposes – it was simply adopted as a complete set. “This Standard provides a framework for timed text to be supported for content delivered via broadband means,…” (see SMPTE-TT).

  However, SMPTE extended TTML in SMPTE-TT with an ability to store a binary blob with captions in another format. This allows using SMPTE-TT as a transport format for any caption format and is deemed to help with “backwards compatibility”.

  Now, instead of specifying a profile, SMPTE decided to define how to convert CEA-608 captions to SMPTE-TT. Even if it’s not called a “profile”, that’s actually what it is. It even has its own namespace : “m608 :”.

  Conclusion

  With all these different versions of TTML, I ask myself what a video player that claims support for TTML will do to get something working. The only chance it has is to implement all the extensions defined in all the different profiles. I pity the player that has to deal with a SMPTE-TT file that has a binary blob in it and is expected to be able to decode this.

  Now, what is a caption author supposed to do when creating TTML ? They obviously cannot expect all players to be able to play back all TTML versions. Should they create different files depending on what platform they are targeting, i.e. a EBU-TT version, a SMPTE-TT version, a vanilla TTML version, and a Simple Delivery Profile version ? Should they by throwing all the features of all the versions into one TTML file and hope that the players will pick out the right things that they require and drop the rest on the floor ?

  Maybe the best way to progress would be to make a list of the “safe” features : those features that every TTML profile supports. That may be the best way to get an “interoperable TTML” file. Here’s me hoping that this minimal set of features doesn’t just end up being the usual (starttime, endtime, text) triple.

  UPDATE :

  I just found out that UltraViolet have their own profile of SMPTE-TT called CFF-TT (see UltraViolet FAQ and spec). They are making some SMPTE-TT fields optional, but introduce a new @forcedDisplayMode attribute under their own namespace “cff :”.