Compressor/Limiter software post-processing of 3GP?

Discussion in 'Amateur Video Production' started by toronado455, Jul 11, 2006.

  1. toronado455

    toronado455 Guest

    I want to apply a compressor/limiter process to the audio of a 3GP
    video. What would be the easiest way to do that?
    toronado455, Jul 11, 2006
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  2. Here's what I would try:

    The free audio editor Audacity has a
    volume compression capability, according to its help file ((I've never
    tried it).

    If you could demux the audio, compress it in Audacity, and remux it,
    you'd be home free!

    Good luck.
    Gene E. Bloch, Jul 11, 2006
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  3. toronado455

    toronado455 Guest

    I use Audacity all the time. It does have a compressor but like you say
    it would require demux/remux of the 3G2 file. (I said 3GP but it is
    actually 3G2). And that would take additional software to perform the
    demux/remux. I was hoping to find some video editing software that
    could also apply compression to the audio track without first having to
    demux the file.
    toronado455, Jul 11, 2006
  4. toronado455

    Ken Maltby Guest

    Not sure that would even be possible. You would need to demux/
    split and remux. The only way around that would be if you can
    accomplished the processing you want during playback.

    There is also a question in my mind as to what you mean by
    compression. Are you talking about an "envelope" factor or
    how much compression was applied (the bitrate used) to encode
    the audio, or are just looking to "normalize" the audio?

    "3GP stores video streams as MPEG-4 or H.263, and audio streams
    as AMR-NB or AAC-LC formats." (Wiki)

    I may have an old copy of Audacity, but it doesn't do AAC much
    less AMR.

    If none of your "Mobile" converters/compressors/encoders will
    let you filter the audio in the fashion you want, consider this:

    You may be able to construct a simple filter graph to convert the
    audio using GraphEdit. With any luck your phone video toys will
    have registered the DSfilters you need to deal with 3GP. Some
    of your other programs may have added other filters you could use.
    You could download "MatrixMixer" DSfilter which should be able
    to fix your audio; after it is demuxed and decoded, but before it is
    then encoded and multiplexed again.

    So, even if you can't find a one button fix, it can be done.

    Ken Maltby, Jul 12, 2006
  5. toronado455

    toronado455 Guest

    I don't know what direct show filters I need. But right now only
    QuickTime will play my 3G2 files with audio. All other software I've
    tried doesn't handle the audio. I believe the audio in my 3G2 files are
    Vorbis 14Kbps mono. The video is 14.609 fps which I think is an odd
    frame rate.

    At this point I'd be happy leaving the audio alone since it's quality
    is not really any worse than the video and just converting the whole
    thing to a more popular format.
    toronado455, Jul 17, 2006
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