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• avcodec/vc2enc : Don't use bitcount when byte-aligned

  6 octobre 2022, par Andreas Rheinhardt

  avcodec/vc2enc : Don't use bitcount when byte-aligned
  (There is a small issue that is now being treated differently :
  
  The earlier code would record a position in a buffer that
  
  is being written to via put_bits(), then write data,
  
  then overwrite the byte at the position recorded earlier
  
  and only then flush the PutBitContext. In case there was
  
  no writeout in the meantime, said flush would overwrite
  
  what one has just written. This never happened in my tests,
  
  but maybe it can happen. In this case this commit fixes
  
  this issue by flushing before overwriting the old data.)
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/vc2enc.c

• init seg_duration option for dash similar to -hls_init_time option

  5 août 2019, par Saurabh

  Is there any option to set first segment duration for dash files, There is similar option for HLS : hls_init_time ?

  I could not found any such option in documentation.

  ---

  Why I want such option to be there :

  From generated DASH files : in Android ExoPlayer, It always plays first chunk of lowest quality(bitrate/resolution), after first chunk, basis user’s internet speed, it picks the next chunk. If there is no init_seg_duration option, I have to rely only on seg_duration and I can not keep it bit large. Why I will like to keep it large : to reduce the number of files generated.

  With such option, I could had given -init_seg_duraion 2 -seg_duration 6, so video quality would had increased after 2 seconds and total number of files generated would also not had exploded.

• Adaptive bit rate streaming of mp4 of different gop size using media source api

  25 décembre 2018, par wahab khurram

  I want the adaptive bitrate streaming of the mp4 video of different gop keyframe size.

  I know there are couple of options for multi bitrate streaming i.e hls, dash etc

  But I already uploaded the videos on the server each video have the 360p, 480p and 720p mp4 file and each video are having different keyframe intervals.

  So the real challenge is to make the own multi bitrate mp4 media player using the media source api

  I have brain storming all aspect.

  We can only cut the h264 at keyframe

  So my real challenge is to know the video each keyframe, the keyframe chunk duration, the offset duration and the offset byte position in the mp4 file.

  So my question is how I can get these following using ffmpeg, ffprobe or any other software.

  1- Keyframe chunk duration

  2- Offset video duration

  3- Offset byte position in video.

  The following ffprobe command give the detailed info of the each keyframe, maybe this will help

  ffprobe -i "1080p.mp4" -select_streams v -skip_frame nokey -show_frames

  Thanks !