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• What is the official website for libavcodec ?

  8 mars 2013, par Ken

  I would like to use libavcodec for a project, the problem is i don't understand where i'm supposed to get the official release, this library is so popular that i can't tell what is the official website.

  for example there are 2 major projects like libav and ffmpeg that are using it but i can't find the official source.

  Where is this website ?

• Is there built in audio preprocessing within Android OS

  28 août 2022, par Larry lu

  I am running a dev team to build an Android application which the major feature is to record user voice and merge it into a long movie. It's a dub film application.

  


  One struggle thing to my dev team is whether the Android OS pre-process the recorded auido file. because we want the very original audio data from the built in Microphone.
If there is a built-in pre-processing inside of Android OS keep updating some data of the recorded aduio file, we want to know what is changed. We can't find any official post from Android speaking about it but would like to confirm from professional.

  


  Many thanks

  


• If multiple channels, merge then take sample length from audio file and save it to s3

  18 mai 2017, par khinester

  I am using transloadit to extract the audio from a video file, which is then saved to S3.
  This works great, but I wanted to know how to :

  1. check if the file has multiple channels and then squash it inot one as per https://transloadit.com/demos/audio-encoding/merging-multiple-audio-streams/ - do I need to check for this or do i default to use this robot ?

  2. extract a small sample from the audio file - and save this as a separate file.

  For example, I have a 2h audio file from which I want to take 5% of the length and save this as sample.mp3

  In ffmpeg, i can cut :

  ffmpeg -ss 0 -t 30 -i original.mp3 sample.mp3

  but I am unsure how to chain this workflow, here is what i have thus far :

  const opts = {
  
    params: {
  
      notify_url: `${ process.env.SELF }/services/trans/${ jwToken }`,
  
      steps:      {
  
        import: {
  
          robot:  '/s3/import',
  
          use:    ':original',
  
          bucket: process.env.S3_INGEST,
  
          path:   ingest.key,
  
          key:    process.env.AWS_ID,
  
          secret: process.env.AWS_SECRET,
  
        },
  
        encode: {
  
          robot:        '/audio/encode',
  
          use:          'import',
  
          ffmpeg_stack: 'v2.2.3',
  
          preset:       'aac',
  
          ffmpeg:       {
  
            ab:  '128k',
  
          },
  
        },
  
        export: {
  
          robot:   '/s3/store',
  
          use:     'encode',
  
          bucket:  s3Export,
  
          path:    `${ prefix }/${ token }.m4a`,
  
          headers: {
  
            'Content-Type': 'audio/mp4',
  
            'x-amz-server-side-encryption': 'AES256',
  
          },
  
          key:    process.env.AWS_ID,
  
          secret: process.env.AWS_SECRET,
  
        },
  
      },
  
    },
  
  };

  in the docs, https://transloadit.com/docs/conversion-robots/ i can’t see how to do this ?

  any advice is much appreciated.