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• How to append fMP4 chunks to SourceBuffer ?

  24 octobre 2020, par Stefan Falk

  I have finally managed to create an fMP4 but now I am not able to seek or play the file depending on what I do in the file.

  


  On my backend I am taking the file and convert it to MP4 or fragmented MP4.

  


  The file gets send to the clients chunk-wise but this approach does not seem to work as it used to work on Chrome (bot not on Firefox) when using MP3.

  


  How I played MP3

  


  Say we have a 10 seconds track that is 1 MB in size which I want to start playing from second five. I want to load chunks of 1 second.

  


  Thus, I have offset = 5 / 10 * file_size and chunkSize = 1 / 10 * file_size`.

  


  With this I just started loading the MP3-file at an offset of 0.5 MB and loaded the chunks as needed where each chunk was 0.1 MB in size.

  


  This worked because before actually playing the file, I loaded the first bytes of the file and appended it to the SourceBuffer as well s.t. it was able to load the meta-information of the file. However, this approach is just not working for fMP4.

  


  What I tried with fMP4

  


  So, I have been converting MP3 to fMP4 with the MP3-approach ..

  


  .. using +dash (can play but not seek)

  


  ffmpeg -i input.mp3 -acodec aac -b:a 256k -f mp4 -movflags +dash output.mp4


  


  .. using frag_keyframe+empty_moov (cannot play on Chrome)

  


  ffmpeg -i input.mp3 -acodec aac -b:a 256k -f mp4 -movflags frag_keyframe+empty_moov output.mp4


  


  On the client the chunks get appended to a SourceBuffer (as explained above) after creating it with the Mime-Type audio/mp4; codecs="mp4a.40.2" :

  


  this.sourceBuffer = this.mediaSource
                        .addSourceBuffer('audio/mp4; codecs="mp4a.40.2"');


  


  and

  


  private appendSegment = (chunk) => {
  try {
    this.sourceBuffer.appendBuffer(chunk);
  } catch {
    return;
  }
}


  


  The problem is that I can only play the +dash converted file if I start reading it from the start and continue adding chunks.

  


  However, if I start reading the file from further down, the audio gets never played.

  


  playTrack(track, 0.0);  // Start at second 0 works
playTrack(track, 10.0); // Start at second 10 does not work


  


• Revision 29188 : 2 options de plus pour personnaliser la page d’activation de la mutu : * ...

  15 juin 2009, par real3t@… — Log

  2 options de plus pour personnaliser la page d’activation de la mutu :
  * ’branding’ : texte libre en HTML
  * ’branding_logo’ => logo (sous forme de HTML)

• ffmpeg nodejs lambda crop issue

  29 juillet 2020, par Ajouve

  I have a lambda function to crop videos with ffmpeg

  


  I am installing the layer this way

  


  #!/bin/bash
mkdir -p layer
cd layer
rm -rf *
curl -O https://johnvansickle.com/ffmpeg/builds/ffmpeg-git-amd64-static.tar.xz
tar -xf ffmpeg-git-amd64-static.tar.xz
mv ffmpeg-git-*-amd64-static ffmpeg
rm ffmpeg-git-amd64-static.tar.xz


  


  I do not really which version but should be recent as I did it today for the last time

  


  Then my node js lambda function is running with the following nodejs module https://github.com/fluent-ffmpeg/node-fluent-ffmpeg

  


  return new Promise((resolve, reject) => {
        ffmpeg(inputFile.name)
            .videoFilters(`crop=${width}:${height}:${x}:${y}`)
            .format('mp4')
            .on('error', reject)
            .on('end', () => resolve(fs.readFileSync(outputFile.name)))
            .save(outputFile.name);


  


  with for example videoFilters('crop=500:500:20:20')

  


  And I have the folowing error

  


  ffmpeg exited with code 1: Error reinitializing filters!
Failed to inject frame into filter network: Invalid argument
Error while processing the decoded data for stream #0:0
Conversion failed!


  


  On my local computer I am running the following command on the exact same image

  


  ffmpeg -i in.mp4 -filter:v "crop=500:500:20:20" out.mp4


  


  my version of ffmpeg is 4.2.2 and this is working great

  


  I do not have the issue with all videos, here one video which is causing me the issue https://ajouve-util.s3.amazonaws.com/earth.mp4