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• Are there people interested in converting ffmpeg source to Go ?

  30 septembre 2018, par No One

  After seeing that Go compiler have been converted from C to Go I thought same for ffmpeg ? Don’t want to go deep into reasons as I think they are obvious. It was very hard to be so close to the have rich library as ffmpeg in other language. It was even hard to make bindings for that scale of library. I’m not enough advanced to start something like this myself, so is there anybody else interested in this ? If yes then where this question worth to be addressed, so people interested in this may have discussion ?

  (Seems not enough obvious so adding some details.)

  For applications which use large amount of commands with different complexity it is hard to read the code as it’s not actually a code. Instead, it’s commands which you will need to understand by reading docs from ffmpeg’s docs page. I had used ffmpeg before in Nodejs and there was lots of logic of manipulating command string. Also sometimes in windows it was ending with cmd limitations error. When you are working with some language it is nice to see whole logic in that language. So you know go ? than you know everything that is happening with this code without even going off from code and reading docs of another application.

  There may be some benefits from executing stuff in goroutines so you can handle concurrency in the way you want not in the way it is implemented in ffmpeg.

  Build faster with Go.

  Less code.

  Possibility to split code into smaller packages.

  Also if you are familiar why community converted compiler from C to Go than I think some reasons will fit too.

• FFMpeg WebVTT hls playlist out of sync [closed]

  29 mai 2023, par user1503606

  I am using the following commands with FFmpeg to encode a .mov video to hls and then also create a playlist for subtitles converting a .srt file to .vtt.

  



  // Creating hls playlist 

ffmpeg -hide_banner -y -i /Users/dave/mermaid.mov -c:a aac -ar 48000 -c:v h264 -profile:v baseline -avoid_negative_ts 0 -start_number 0 -hls_time 10 -hls_playlist_type vod -hls_list_size 0 -f hls -vf scale=w=640:h=360:force_original_aspect_ratio=decrease -b:v 800k -maxrate 856k -bufsize 1200k -b:a 96k -hls_segment_filename /Users/dave/mermaid/360/360p_%03d.ts /Users/dave/dave/mermaid/360/360p.m3u8 
-c:a aac -ar 48000 -c:v h264 -profile:v baseline -avoid_negative_ts 0 -start_number 0 -hls_time 10 -hls_playlist_type vod -hls_list_size 0 -f hls -vf scale=w=842:h=480:force_original_aspect_ratio=decrease -b:v 1400k -maxrate 1498k -bufsize 2100k -b:a 128k -hls_segment_filename /Users/dave/Desktop/mermaid/480/480p_%03d.ts /Users/dave/Desktop/mermaid/480/480p.m3u8 
-c:a aac -ar 48000 -c:v h264 -profile:v baseline -avoid_negative_ts 0 -start_number 0 -hls_time 10 -hls_playlist_type vod -hls_list_size 0 -f hls -vf scale=w=1280:h=720:force_original_aspect_ratio=decrease -b:v 2800k -maxrate 2996k -bufsize 4200k -b:a 128k -hls_segment_filename /Users/dave/Desktop/mermaid/720/720p_%03d.ts /Users/dave/Desktop/mermaid/720/720p.m3u8 
-c:a aac -ar 48000 -c:v h264 -profile:v baseline -avoid_negative_ts 0 -start_number 0 -hls_time 10 -hls_playlist_type vod -hls_list_size 0 -f hls -vf scale=w=1920:h=1080:force_original_aspect_ratio=decrease -b:v 5000k -maxrate 5350k -bufsize 7500k -b:a 192k -hls_segment_filename /Users/dave/Desktop/mermaid/1080/1080p_%03d.ts /Users/dave/Desktop/mermaid/1080/1080p.m3u8

// Creating subtitles

ffmpeg -i /Users/dave/mermaid.mov -i /Users/dave/little-mermaid.srt -c copy -c:s webvtt -start_number 0 -hls_time 10000000 -hls_flags single_file -hls_playlist_type vod -f hls -avoid_negative_ts 0 /Users/dave/mermaid/English/master.m3u8


  



  I am also doing this with AWS Media Convert the AWS conversion works fine the subtitles are perfectly in time but the FFMPEG version seems to be out of sync by about 1 second.

  



  Here are both files for to compare the exact same files are used for both.

  



  AWS Media Convert : https://d25hd5yfabpc2n.cloudfront.net/c0017bfe-3617-47a5-9525-86d69c73cf57/master.m3u8

  



  Local FFMPEG : https://d25hd5yfabpc2n.cloudfront.net/stackoverflow/master.m3u8

  



  The only thing I can see if I download both playlists is the AWS one has FRAME-RATE set.

  



  Here is an example of both videos playing the FFMEPG one is noticeably out of sync

  



  https://output.jsbin.com/xopohupivu/

  



  Another thing I have noticed is the AWS webvtt version has this at the top of the webvtt file.

  



  WEBVTT  #Elemental Media Engine(TM) 2.16.0.602399
X-TIMESTAMP-MAP=LOCAL:00:00:00.000,MPEGTS:191970


  



  Not sure what is happening here can't find any information on how to implement this with FFMPEG.

  



  Thanks

  


• Anomalie #4272 : Vignettes considérée comme orphelins lors de la suppression des documents inutilisés

  11 février 2019, par Fabrice Véronneau

  Discussions sur le forum à ce sujet
  https://forum.spip.net/fr_271022.html
  https://forum.spip.net/fr_270796.html?debut_forums=%40270837#forum270837