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• Create different qaulities for my manifest with only mp4box

  29 septembre 2020, par Ted Bed

  I asked a question on slack on why the quality and bitrate of my dash video wasn't changing and I got this response : You only have one quality in your manifest. there is no way for the player to choose a different one

  


  So how can I create different "qualities" ?

  


  I have a mp4box command like :

  


  MP4Box -dash 2000 -profile dashavc264:live -bs-switching multi -url-template whatever.mp4#trackID=1:id=vid0:role=vid0 whatever.mp4#trackID=2:id=aud0:role=aud0 -out whatever.mpd


  


  Would it be possible to create different "qualities" with only mp4box or would I have to create the same video with different resolutions with something like ffmpeg and then feed them into the inputs to the command above ?

  


• webm_dash_manifest : Add option to specify bandwidth

  12 avril 2017, par Vignesh Venkatasubramanian

  webm_dash_manifest : Add option to specify bandwidth
  Add an option to webm_dash_manifest demuxer to specify a value for
  
  "bandwidth" field in the DASH manifest. The value is then used by
  
  the muxer. Fixes an existing FIXME in the code.
  Signed-off-by : Vignesh Venkatasubramanian <vigneshv@google.com>
  
  Signed-off-by : James Zern <jzern@google.com>
  

  • [DH] libavformat/matroskadec.c
  • [DH] libavformat/webmdashenc.c
  • [DH] tests/fate/vpx.mak
  • [DH] tests/ref/fate/webm-dash-manifest-live-bandwidth

• How to not add AdaptationSet for audio if audio stream is not present in input file

  13 juin 2019, par Saurabh

  I am using ffmpeg-dash to create mpd files. I am using following command to generate the same :

  ffmpeg -i input/video.mov \
  
          -map 0:v:0 -map 0:v:0 -map 0:v:0 -map 0:a\?:0 \
  
          -b:v:0 350k -c:v:0 libx264 -filter:v:0 "scale=320:-1" \
  
          -b:v:1 1000k -c:v:1 libx264 -filter:v:1 "scale=640:-1" \
  
          -b:v:2 3000k -c:v:2 libx264 -filter:v:2 "scale=1280:-1" \
  
          -use_timeline 1 -use_template 1 -window_size 6  -adaptation_sets "id=0,streams=v id=1,streams=a"  \
  
          -seg_duration 2 -threads 16 -hls_playlist true -f dash output/ffmpeg/output.mpd

  This works with video which has audio streams, but for the case there is no audio stream in the video file, I get empty entry for audio in mpd files like following, which is not valid and fails while playing in Exo Player in Android.

  <adaptationset contenttype="audio" segmentalignment="true" bitstreamswitching="true">
  
  </adaptationset>

  I tried adding ? in option adaptation_sets like : id=0,streams=v id=1,streams=a?, however that also adds above line.

  One solution is to run different commands for different videos by first checking whether there is audio stream or not, but would be better if there is some option which add audio adaptationSet only if audio stream is present in the input file.