Edit mpg audio... how?

Discussion in 'Mac Apps and Mac App Store' started by Brendon Bauer, Oct 31, 2007.

  1. Brendon Bauer macrumors 6502

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    #1
    I have two videos that were recording with too little audio input. The sound is just someone talking, so it shouldn't be too hard to raise the volume a bit. In fact, the sound is so low that I have to turn my volume (on my mbp) all the way up for it to sound like a normal, but quiet, person. I've tried raising the volume in qtpro, saving, raising it again, saving, etc, but it doesn't work. I've tried turning things up in iMovie '08 also.... this is driving me crazy. No program allows me to turn it up as far as I need it. I'm not worried about losing quality--I know that will happen. I'd rather sacrifice quality to make it audible. Does anyone know of any simple programs I can use to edit movie audio?

    Thanks
     
  2. superleccy macrumors 6502a

    superleccy

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    #2
    You should be able to use File > Export in Quicktime Pro to extract the audio track.

    Then open the audio track in something like Audacity (free) or Sound Studio (not free) to normalise the track.

    Then use something like iMovie HD '06 to graft the audio track back onto the video. As a iLife '08 user, you can download the much-more-powerful iMovie HD '06 from the Apple website for free. The link is on this forum somewhere (I saw someone ask about it earlier today).

    Good luck!
    SL
     
  3. Brendon Bauer thread starter macrumors 6502

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    #3
    I'm not able to find where you can extract just audio in Quicktime Pro. I only see options for exporting the video as a whole.
     
  4. superleccy macrumors 6502a

    superleccy

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    #4
    Whoops yes. For some reason, QTPro doesn't let you export the audio of a muxed MPEG file. It works with other formats, but I guess that's no use for you. :(

    You could certainly capture the audio using Audio Hijack - but I'm sure there's an app out there that can provide a more elegant solution. I'll post back if I remember what it is.

    SL
     
  5. superleccy macrumors 6502a

    superleccy

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    #5
    Got it! Go find and download the free MPEG Streamclip.

    Open your mpg file with MPEG Streamclip, and do File > Demux to m2v and AIFF...

    SL
     
  6. Brendon Bauer thread starter macrumors 6502

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    #6
    Is .m2v a video format? Quicktime can't play it, and I can't import it into iMovie HD 6. So as I understand it, demux means to separate? So I was separating the movie into .aiff audio and .m2v video? I'm not sure how to get it back together with the video, because I can't use .m2v with anything...
     
  7. Brendon Bauer thread starter macrumors 6502

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    #7
    I used visualhub to convert m2v into .dv, which iMovie can read. Not sure if thats an elegant solution, but I think it's going to work. I'll just patch em back together then.
     
  8. Brendon Bauer thread starter macrumors 6502

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    #8
    After converting it to dv, my movie was 36 min and my audio was only 30 minutes lol... now everything is out of sinc :(. Not sure what to do. I don't know what i can do with m2v files...
     
  9. superleccy macrumors 6502a

    superleccy

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    #9
    Yes, Demux = Demultiplex = Separate.

    The .m2v file is the video part of the your original mpg file. The .aif file is the sound part.

    Ignore the .m2v file, and process the .aif file using Audacity or similar to get the sound you are happy with.

    Then create a blank iMovie HD '06 project, selecting DV as the video format.

    Drag your original .mpg file into iMovie. iMovie will internally convert it to DV format, but without the sound.

    Then, graft processed .aif file into the project. Everything should be the same length.

    Finally, using the expert settings options in iMovie, export to whatever format you want.

    Should work. In fact I just tried it now and it worked for me. Good luck!

    SL
     

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