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• ffmpeg video CodecContext picture height can't be changed

  19 août 2015, par Kaidul Islam

  I am writing h264 encoded video data into mov container using ffmpeg. Initially I created video stream using avformat_new_stream and set video stream codec context’s attributes like this -

  // .......
  
  // .....
  
  pCodecCtx->bit_rate = VIDEO_BIT_RATE;
  
  pCodecCtx->width = 176;
  
  pCodecCtx->height = 244;
  
  pCodecCtx->pix_fmt = STREAM_PIX_FMT;    

  Then when I’ve received the first video frame, I tried to change the pCodecCtx->width and pCodecCtx->height to parsed W/H from SPS frame.

  SpsParser().GetPictureDimSpsFrame(pData, m_nPictureWidth, m_nPictureHeight);
  
  AVCodecContext* pCodecCtx = m_pVideoStream->codec;
  
  pCodecCtx->width = m_nPictureWidth; // 288
  
  pCodecCtx->height = m_nPictureHeight; // 352

  The video width has been changed successfully but the height can’t be overridden. When I tried to see the media file properties using mediainfo dump.mov, it showed :

  Width: 288 // well, changed
  
  Height: 244 // not changed
  
  Original height: 352

  Why the height can’t be overridden ? What to do ? Thanks in advance !

• Getting video sped-up with FFmpeg to have the correct duration

  1er septembre 2015, par Vincent Tjeng

  I’ve been speeding up video using ffmpeg by following these instructions. For example, to speed up the video by 4 times, I run the following command :

  ffmpeg -i vid.MP4 -filter:v "setpts=0.25*PTS" vid_fast.MP4

  While the video is sped up by the indicated amount, the duration of the video (as indicated under its properties, and also when I play the video in VLC) remains the same as the original. For example, if vid.MP4 is initially 4 minutes, then vid_fast.MP4 is also 4 minutes, rather than being 1 minute long as expected. (The additional 3 minutes just consist of the video being frozen on the last frame.)

  This is a bit of a hassle, since I need to delete the additional 3 minutes that I’m not interested in. Is there any way to avoid this ?

  Here is a bit more information on the version of ffmpeg I’m using :

  ffmpeg version N-69060-gcd960c8 Copyright (c) 2000-2015 the FFmpeg developers
  
    built on Jan 14 2015 22:13:45 with gcc 4.9.2 (GCC)
  
    configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-av
  
  isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enab
  
  le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --
  
  enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-lib
  
  modplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrw
  
  b --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libschroedinge
  
  r --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --en
  
  able-libvidstab --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-libvorbis
  
   --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
  
  libx265 --enable-libxavs --enable-libxvid --enable-lzma --enable-decklink --enab
  
  le-zlib
  
    libavutil      54. 16.100 / 54. 16.100
  
    libavcodec     56. 20.100 / 56. 20.100
  
    libavformat    56. 18.101 / 56. 18.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5.  7.101 /  5.  7.101
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  3.100 / 53.  3.100
  
  Hyper fast Audio and Video encoder

• dnxhd : add better support for CIDs 1270 to 1274

  28 septembre 2015, par Jeremy James

  dnxhd : add better support for CIDs 1270 to 1274
  These are DNxHR profiles with the following properties :
  
   Variable size in a profile (property added in a previous commit),
  
    requiring variable-sized macroblock table ;
  
   Variable bitdepth, up to 12 bits.
  
   Better validation of buffer sizes and positions
  Signed-off-by : Christophe Gisquet <christophe.gisquet@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavcodec/dnxhddata.c
  • [DH] libavcodec/dnxhddec.c