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• 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

     


     

     


  


  


• FFMPEG UDP to DASH I am wondering if it could be written more efficiently ?

  18 mars 2019, par c7borg

  I have the below working but it is quite cpu intensive I’ve just moved to ffmpeg 3.4 and was wondering if it could be written more efficently ?

  The below takes a multicast stream from our local LAN avoids the choppy footage by using the scenecut then adjusts the audio with the async to keep it in time and uses the yadif to deinterlace to provide better quality. This command/script also trims the maximum number of segments otherwise with a live stream it would fill up the directory.

  If anyone has any improvements I’d much appreciate it

  I also add subtitles using -filter_complex "[0:v][0:s]overlay" but this conflicts with the -vf yadif option.

  ffmpeg -i \
  
  "udp://@239.192.4.5:1234?overrun_nonfatal=1&fifo_size=50000000" \
  
  -acodec aac -strict -2 -vcodec libx264 \
  
  -vf yadif \
  
  -af aresample=async=1 \
  
  -x264opts 'keyint=25:scenecut=-1' \
  
  -window_size 10 -extra_window_size 10 \
  
  -f dash /var/www/html/stream/out.mpd

  If it can’t be written more efficiently at least this may help others as it took me a long time to get this far. For reference I use shaka player in chromium for the client side