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• How to grab specific segments of M3U8 via ffmpeg ?

  30 juillet 2020, par Lysander Cox

  I recently asked baout how I could download segments of an online m3u8 file, and someone pointed out that this could be accomplished via ffmpeg :

  


  ffmpeg -i [LINK] -codec copy [OUTPUT FILE] #downloads only audio segments;
ffmpeg -i [LINK] -bsf:a aac_adtstoasc -vcodec copy -c copy -crf 50 [OUTPUT] #downloads audio and video segments


  


  For those who aren't familiar, m3u8 is formatted kinda of like a "playlist", with an m3u8 file pointing to a bunch of smaller "segments" which are pieced together to form the whole of the video. As a result, it's completely possible to halt the above commands partway through their execution and still produce a watchable video (i.e. one that will be interpreted correctly by video editors).

  


  I'm wondering if there's a built-in method with ffmpeg that allows me to grab segments N-M of a given m3u8. If there are methods outside of ffmpeg, feel free to mention them as well. Thanks for the help.

  


• ffmpeg video stream to app c# [on hold]

  3 septembre 2014, par Alexey Medvedev

  I am trying to make a video mixer for online broadcasts. To do this, I use ffmpeg and C #. I had a problem with the transfer of the video stream from ffmpeg to my program. I would like to receive a stream of ffmpeg using network protocols (e.g. TCP, UDP or others) or capturing if from ffplay window, but I don`t how I can do it. Can you give me some ideas ?

  For example, I have command for ffmpeg : "ffmpeg -i video1.mp4 -f mpegts udp:127.0.0.1:5000" or same command with other output formats or network protocols. How i can read video stream from the port and convert it to Bitmap ?
  I need to send video stream from my program from computer A to my program to computer B. I write program on C#. I dont know how I can compress video which I must send between my computers and I decided to use Ffmpeg. Now, I can streaming video from my program in computer A to ffmpeg and compress it with parameters which I need.
  On second computer I can read this steam using ffmpeg or ffplay, but I don`t know how I can get this stream into my program.
  1) How can I get this stream in my program ? Which libraries can you recommend me ?
  2) Do you know any libraries which can compress video, instead of using ffmpeg ?

• Anomalie #3248 (Nouveau) : Les fonctions parametre_url (js et php) n’insèrent pas correctement les...

  26 juillet 2014, par Michel Bystranowski

  L’appel
  

  parametre_url(’http://domaine/spip.php?t[]=1’,’t’,array(0,2)) ;
  

  
  retourne
  

  http://domaine/spip.php?t[]=1&t[]=0&t[]=2
  

  
  au lieu de
  

  http://domaine/spip.php?t[]=0&t[]=2
  

  Ce problème est présent à la fois dans la version javascript et la version php. Je n’ai testé que sur SPIP 3.0.16.

  J’ai un patch qui corrige ça dans les deux cas.

  Pour le javascript, il y a une regexp mal échappée, et un appel à la fonction substring avec un index négatif, ce qui n’est pas permis, seule la fonction substr le permet… (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring)

  Et dans les deux cas, il faut bien vider les valeurs initiale du tableau dans l’url avant d’ajouter les nouvelles valeurs.

  Je joins des fichiers corrigés, et voici un patch :

  2 files changed, 9 insertions(+), 3 deletions(-)
   2014/ecrire/inc/utils.php             | 5 +++++
   2014/prive/javascript/ajaxCallback.js | 7 ++++---
      Modified   2014/ecrire/inc/utils.php
  
  diff —git a/2014/ecrire/inc/utils.php b/2014/ecrire/inc/utils.php
  
  index b875aa2..01a7f53 100644
  
  — - a/2014/ecrire/inc/utils.php
  
  +++ b/2014/ecrire/inc/utils.php
  
  @@ -333,6 +333,11 @@ function parametre_url($url, $c, $v=NULL, $sep=’&amp ;’) 
  
                   $url[$n] = $r[1].’=’.$u ;
  
                   unset($ajouts[$r[1]]) ;
  
               
  
  +            // Pour les tableaux on laisse tomber les valeurs de
  
  +            // départ, on remplira à l’étape suivante
  
  +            else 
  
  +                unset($url[$n]) ;
  
  +            
  
           
  
       
      Modified   2014/prive/javascript/ajaxCallback.js
  
  diff —git a/2014/prive/javascript/ajaxCallback.js b/2014/prive/javascript/ajaxCallback.js
  
  index 118fc31..de434c4 100644
  
  — - a/2014/prive/javascript/ajaxCallback.js
  
  +++ b/2014/prive/javascript/ajaxCallback.js
  
  @@ -809,7 +809,7 @@ function parametre_url(url,c,v,sep,force_vide)
  
       
  
           else
  
               a=url ;
  
   var regexp = new RegExp(’^(’ + c.replace(’[]’,’[]’) + ’[?] ?)(=.*) ?$’) ;
  
  +    var regexp = new RegExp(’^(’ + c.replace(’[]’,’[]’) + ’[?] ?)(=.*) ?$’) ;
  
       var ajouts = [] ;
  
       var u = (typeof(v) !==’object’) ?encodeURIComponent(v):v ;
  
       var na = [] ;
  
  @@ -829,11 +829,12 @@ function parametre_url(url,c,v,sep,force_vide)
  
               
  
               // Ajout. Pour une variable, remplacer au meme endroit,
  
               // pour un tableau ce sera fait dans la prochaine boucle
  
   else if (r[1].substring(-2) != ’[]’) 
  
  +            else if (r[1].substr(-2) != ’[]’) 
  
                   na.push(r[1]+’=’+u) ;
  
                   ajouts.push(r[1]) ;
  
               
  
   else na.push(args[n]) ;
  
  +            /* Pour les tableaux ont laisse tomber les valeurs de départ, on
  
  +                 remplira à l’étape suivante */
  
           
  
           else
  
               na.push(args[n]) ;