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• 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

• 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.

  


• FFMPEG DASH Issues

  5 octobre 2022, par user726720

  I have a couple of questions regarding ffmpeg.

  


  


  1. First is i can't seem to get the frame rate correctly.

     


     

     


     I'm expecting 25, i have tried both , both give me the same result.

     


     -r 25 and -filter:v fps=25


     


     Here is my complete command im using

     


     ffmpeg -re -i file.mxf -pix_fmt yuv420p -vsync 1 -map 0:v:0 -map 0:a:0 -c:a aac -c:v libx264 -use_template 1 -use_timeline 1 -init_seg_name  "init-stream$RepresentationID$-$Bandwidth$.mp4" -media_seg_name "chunk-stream$RepresentationID$-$Number%05d$.$ext$" -b:v 2000k -b:a 48k -ac 2 -profile:v main -level:v 3.0 -s 640x360  -filter:v fps=25 -vsync passthrough -increment_tc 1 -adaptation_sets "id=0,streams=v id=1,streams=a" -g 100 -keyint_min 100 -seg_duration 5 -frag_duration 5 -dash_segment_type auto -f dash stream.mpd


     


  


  2. My second question is related to the use of audio, with the above command im acheiving the below results, with the use of AAC

     


     

     


     But my target is to acheive the below, how do i go about this

     


     

     


     

     3. How do i change the muxing mode to dash

     


     


     

     


     Like the below