Recherche avancée

Sur d’autres sites (9763)

• FFmpeg 6 taking more time than FFmpeg 5 for dash file generation

  9 mars 2023, par QCoder

  I tried to generate a MPD file along with the audio and video stream files using the dash muxer in FFmpeg. This is the command I am using :

  


  ffmpeg -y -i video.mp4 -f dash mpd_file


  


  I tried it on 34 min video. For FFmpeg [5.1.2] it took almost 2min 10 sec to generate everything and for FFmpeg [6.0] it took about 4min 41 sec. Amost double the time.

  


  I tried trimming also and for that also the time comparison was almost same, FFmpeg 6 took double the time than that of FFmpeg 5.

  


  What could be the possible reason for it ? Am I missing some flag for FFmpeg 6 or is there any new addition ? Because when I checked the release notes of FFmpeg 6, there was no new filter which was added related to this particular case.

  


  I tested this comparison on the same machine and it is very unbelievable that FFmpeg 6 is taking so much time, considering this is a new and an advanced version of FFmpeg 5.

  


• avformat/{isom,mov,movenc} : add support for CMAF DASH roles

  15 juillet 2021, par Jan Ekström

  avformat/isom,mov,movenc : add support for CMAF DASH roles
  This information is coded in a standard MP4 KindBox and utilizes the
  
  scheme and values as per the DASH role scheme defined in MPEG-DASH.
  
  Other schemes are technically allowed, but where multiple schemes
  
  define the same concepts, the DASH scheme should be utilized.
  Such flagging is additionally utilized by the DASH-IF CMAF ingest
  
  specification, enabling an encoder to inform the following component
  
  of the roles of the incoming media streams.
  A test is added for this functionality in a similar manner to the
  
  matroska test.
  Signed-off-by : Jan Ekström <jan.ekstrom@24i.com>
  

  • [DH] libavformat/isom.c
  • [DH] libavformat/isom.h
  • [DH] libavformat/mov.c
  • [DH] libavformat/movenc.c
  • [DH] libavformat/version.h
  • [DH] tests/fate/mov.mak
  • [DH] tests/ref/fate/mov-mp4-disposition-mpegts-remux

• 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.