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• Implementing '-async 1' in C code to correct out of sync audio

  25 septembre 2013, par Christian P.

  I have built a segmenter that takes as input a h264 / AAC video and segments according to the HLS specification. The source code for it can be seen here : https://gist.github.com/cpnielsen/f36729c371aac0fe535d

  It is implemented as a python extension, but the interesting parts are in the process_video() function. It makes use of the libav library (alternatively ffmpeg) to do the heavy lifting.

  It works 95% of the time, but we have come upon some videos where it produces segments with audio out of sync. If I was using the command-line tool, I could simply add -async 1 to fix it, but how do I implement the same functionality in my C code ?

  I found a snippet of code in avconv_filter.c (for libav, not sure what the ffmpeg equivalent is) where they initiate the filter, but without any documentation it is hard to figure out how to do this outside the whole modular setup.

  I just need to :

  1. Initiate the correct filter
  2. Apply it to the input (or output ? not sure)
  3. Know of any pitfalls when using the filter.

  Any help is welcome ; sample code, explanation of the filter, etc.

• Ffmpeg returning error code 1 in AWS Lamda function

  14 avril 2018, par Tometoyou

  I’m running a lambda function which takes an mp4 video, and adds a watermark of a png image over the top of it in the bottom right hand corner (with a 10px margin). It then outputs that image to a temporary location. It keeps failing with Error code 1, but that isn’t very helpful. I’m using a binary version of ffmpeg that is specified in the main directory of the code. I know that ffmpeg is set up correctly due to using it in another lambda function in this way, which works. But adding an overlay fails. Here is the relevant part of my code :

  function addWatermark(next) {
  
      var ffmpeg = child_process.spawn("ffmpeg", [
  
        "-i", target, // url to stream from
  
        "-i", watermarkPath,
  
        "-filter_complex" ,"overlay=x=W-w-10:y=H-h-10:format=rgb,format=yuv420p",
  
        "-c:a", "copy",
  
        "pipe:1"
  
      ]);
  
      ffmpeg.on("error", function(err) {
  
        console.log(err);
  
      })
  
      ffmpeg.on("close", function(code) {
  
        if (code != 0 ) {
  
          console.log("child process exited with code " + code); // Always exits here.
  
        } else {
  
          console.log("Processing finished !");
  
        }
  
        tmpFile.end(); 
  
        next(code);
  
      });
  
      tmpFile.on("error", function(err) {
  
        console.log("stream err: ", err);
  
      });
  
      ffmpeg.on("end", function() {
  
        tmpFile.end();  
  
      })
  
      ffmpeg.stdout.pipe(tmpFile)
  
      .on("error", function(err){
  
        console.log("error while writing: ",err);
  
      });
  
  }

  Can anyone spot what may be wrong ?

  UPDATE

  I’ve managed to print out some more logs, I’m getting the error :

  [NULL @ 0x42923e0] Unable to find a suitable output format for 'pipe:1'

• Anomalie #4264 (Nouveau) : espace après code

  4 janvier 2019, par Maïeul Rouquette

  Testé sur contrib ce jour

  Soit le texte suivant

  1. <span class="CodeRay">[&amp;lt;code&amp;gt;#GENERER_SAISIES&amp;lt;/code&amp;gt;-&amp;gt;3364#GENERER_SAISIES].
  2. </span>

  Télécharger

  (note : il y a problème d’affichage, car redmine ne permet pas d’avoir une balise code dans du code, visiblement.

  Textwheel ajoute une espace entre la balise code fermante et la balise a fermante, ce qui est problèmatique.