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• Revision 6b7ec50812 : fixed a bug of context overwritten by key frame recoding The recoding loop save

  15 mars 2012, par Yaowu Xu

  Changed Paths : Modify /vp8/encoder/ratectrl.c fixed a bug of context overwritten by key frame recoding The recoding loop save and restore frame coding context for recodes. However in recoding of key frames, some of the coding context saved was stale from last encoded inter frame. The (...)

• avcodec/hevcdec : fix stat_coeff save/load for persistent_rice_adaptation_enabled_flag

  15 novembre 2020, par Xu Guangxin

  avcodec/hevcdec : fix stat_coeff save/load for persistent_rice_adaptation_enabled_flag
  It's required by the 9.3.1 TableStatCoeff* section.
  Following clips have this feature :
  
  WPP_HIGH_TP_444_8BIT_RExt_Apple_2.bit
  
  Bitdepth_A_RExt_Sony_1.bin
  
  Bitdepth_B_RExt_Sony_1.bin
  
  EXTPREC_HIGHTHROUGHPUT_444_16_INTRA_10BIT_RExt_Sony_1.bit
  
  EXTPREC_HIGHTHROUGHPUT_444_16_INTRA_12BIT_RExt_Sony_1.bit
  
  EXTPREC_HIGHTHROUGHPUT_444_16_INTRA_8BIT_RExt_Sony_1.bit
  
  EXTPREC_MAIN_444_16_INTRA_10BIT_RExt_Sony_1.bit
  
  EXTPREC_MAIN_444_16_INTRA_12BIT_RExt_Sony_1.bit
  
  EXTPREC_MAIN_444_16_INTRA_8BIT_RExt_Sony_1.bit
  
  WPP_AND_TILE_10Bit422Test_HIGH_TP_444_10BIT_RExt_Apple_2.bit
  
  WPP_AND_TILE_AND_CABAC_BYPASS_ALIGN_0_HIGH_TP_444_14BIT_RExt_Apple_2.bit
  
  WPP_AND_TILE_AND_CABAC_BYPASS_ALIGN_1_HIGH_TP_444_14BIT_RExt_Apple_2.bit
  
  WPP_AND_TILE_HIGH_TP_444_8BIT_RExt_Apple_2.bit
  you can download them from :
  
  https://www.itu.int/wftp3/av-arch/jctvc-site/bitstream_exchange/draft_conformance/RExt/
  Signed-off-by : Xu Guangxin <oddstone@gmail.com>
  
  Signed-off-by : Linjie Fu <linjie.justin.fu@gmail.com>
  

  • [DH] libavcodec/hevc_cabac.c
  • [DH] libavcodec/hevcdec.c
  • [DH] libavcodec/hevcdec.h

• I am trying to save frames from a webcam via Python and ffmpeg, but the video becomes way to fast

  10 mai 2022, par Matthias

  I get a stream of cv2 images from my webcam and want to save it to a video file. After playing a bit with cv2.VideoWriter() it turned out that using ffmpeg would provide more options and - apparently, following a few threads here on SO - lead to better results. So I gave the VidGear Python library a try, and it seems to work fine.

  


  There is one catch though : My webcam provides a variable framerate, most of the time between 10 and 30 FPS. When saving these frames the video file becomes way too fast, like watching in fast-forward. One real-time minute becomes only a few seconds in the video.

  


  I tried to play with various combinations of the ffmpeg's -framerate and/or -r parameters, but without luck. Here is the command I am using right now :

  


  ffmpeg -y -f rawvideo -vcodec rawvideo -s 1920x1080 -pix_fmt bgra -framerate 25.0 -i - -vcodec libx265 -crf 25 -r 25 -preset fast 


  


  For the records, I am creating the WriteGear class from the VidGear library like this :

  


  video_params = {
    "-vcodec": "libx265",
    "-crf": 25,
    "-input_framerate": 25,
    "-r": 25,
}
WriteGear(output_filename=video_file, logging=True, **video_params)


  


  Any ideas what I am doing wrong here and how I need to call ffmpeg ?