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• Calculate Bitrate from m3u8 ts files ffmpeg

  16 janvier 2017, par John

  I im using ffmpeg to connect to source and then make hls chunks (ts files) so that i can restream.

  I use following ffmpeg command to connect to source and generate hls segments :

  ffmpeg -y -nostdin -hide_banner -fflags +genpts -async 1 -i http://livestream.com/stream_name.ts -acodec copy -vcodec copy -scodec copy -f hls -hls_time 10 -hls_list_size 6 -hls_flags delete_segments /tmp/chunks/1_.m3u8

  Files are generated in /tmp/chunks/ folder ==>♦ 1_.m3u8 index file and 1_0.ts 1_1.ts 1_2.ts 1_3.ts

  So question is how can i calulate bitrate of stream ?

  If i use -f mpegts i can see from ffmpeg bitrate in terminal...but i don’t have chunks and opening stream is slow because stream is written in one file 1_.m3u8 on HDD and is growing..so this solution is not good.

  I use to calulate this way :

  When 1_1.ts is generated i read file size of 1_0.ts, read duration of 1_0.ts and calulate bitrate....let’s say that file size is : 2360904 bytes and file duration is : 12seconds) :

  I calucalte it using forumula :

  BITRATE = ((file_size / 1024) / file_duration) * 8 [kbit/s]

  So in my example this is :

  BITRATE = ((2360904 / 1024) / 12) * 8 = 1537 [kbit/s]

  Is this correct calulation and is this valid for ffmpeg ? Because in ffmpeg when i don’t use hls segmenter only -f mpegts i get bitrate around 1770kbit/s so would need to ask if this is correct way of calculating bitrate of stream or if is not how is correct way and formula...thanks.

  Also i need to use HLS segmenter from ffmpeg because this way streams opens very quick and cpu usage is lower (ram usage is 1-2MB per connection witch is good)

• Delay in video playback. Not able to identify the cause - AWS S3 region / ffmpeg / Videojs

  17 septembre 2016, par Himansu Kisan

  We are not able to identify the cause for random behavior while playing video on our website. (Sorry, cant share a link since the videos are for registered users only)
  The videos sometimes plays instantly and sometimes it takes over 1 minute to start. Not sure what we are doing wrong.

  We are using AWS S3 Oregon region (not the closest to target region, but it is cheaper) to store video files.
  The video files are encoded using ffmpeg. Below is the syntax

  ffmpeg -i input.mts -codec:v libx264 -threads 4 -movflags +faststart -profile:v high -preset slow -b:v 500k -maxrate 500k -bufsize 1000k -vf scale="trunc(oh*a/2)*2:720" "output.mp4"

  ffmpeg -i input.mts -codec:v libvpx -threads 4 -quality good -cpu-used 5 -b:v 500k -maxrate 500k -bufsize 1000k -qmin 10 -qmax 42 -vf scale="trunc(oh*a/2)*2:720" -codec:a libvorbis -b:a 128k "output.webm"

  On website, we are using Videojs 5.10.8.
  Below is the code snippet

   <video class="video-js vjs-default-skin vjs-big-play-centered" preload="none" controls="controls" poster="abcd.jpg" style="width:100%;height:100%;min-height:360px;" data-setup="{&quot;autoplay&quot;:true}">
  
  <source src="abcd.mp4" type="video/mp4"></source>
  
  <source src="adcd.webm" type="video/webm"></source>
  
  <p class="vjs-no-js">
  
      To view this video please enable JavaScript, and consider upgrading to a web browser
  
      that <a href="http://videojs.com/html5-video-support/" target="_blank">supports HTML5 video</a>
  
  </p>
  
  </video>

  What are we doing wrong ? Please help us out.

• Anomalie #4122 (Fermé) : mise à jour du modele vidéo

  1er avril 2018, par Franck D

  Hello :-)
  Juste pour dire que depuis spip 3.2, il y a dans le modele vidéo, l’appel d’un fichier qui n’est plus présent depuis la mise à jour de la lib
  https://zone.spip.org/trac/spip-zone/browser/_core_/plugins/medias/modeles/video.html#L17
  https://zone.spip.org/trac/spip-zone/browser/_core_/plugins/medias/modeles/video.html#L30
  https://zone.spip.org/trac/spip-zone/browser/_core_/plugins/medias/modeles/video.html#L31

  Nous appelons lib/mejs/flashmediaelement.swf mais ce fichier n’existe plus, pareil, il y a aussi
  https://zone.spip.org/trac/spip-zone/browser/_core_/plugins/medias/modeles/video.html#L46
  css/mejs-skin Je suis pas sûr que cela soit encore utile ?
  Franck