GUI app for remuxing streams from an AVI container into an MP4?

Discussion in 'Digital Video' started by Makosuke, Aug 6, 2010.

  1. Makosuke macrumors 603

    Joined:
    Aug 15, 2001
    Location:
    The Cool Part of CA, USA
    #1
    I've got a handful of AVI files on hand that use h264 video and MP3 audio (seriously, it's 2010, switch to AAC already). They play fine, but I'd prefer having the video in an MP4 container.

    I'm therefore wondering if there's an app that will do this kind of passthrough remux that I've missed.

    I'm aware that ffmpeg can do it via the command line, but I was hoping for a GUI if such a thing exists. The ffmpegX GUI frontend doesn't seem to allow passthrough with an MP4 container, only AVI. Avidemux will do exactly what I want, except the MP4 files it produces don't work in QT Player for some reason--based on some forum threads there, this appears to be a longstanding issue that they don't care to fix for whatever reason.

    Are there any other remux apps like these, or is there some option I'm overlooking in one or the other that will allow me to do what I want?

    (Incidentally, QT Pro will of course allow me to extract the audio and video track into a new movie, and save it lossless as a .mov, which is pretty close to an MP4, but I was rather hoping for an actual MP4 container. The MP4 export does have a passthrough option in QT Pro, but it is grayed out... is this always gray, or is there something funky with the h264 track in my files?)
     
  2. lostless macrumors 6502

    Joined:
    Oct 22, 2005
    #2
    You can not demux/remux to mpeg 4. Divx (which uses the avi container) contains mpeg 4 part 2 video, but does not perfectly conform to actual mpeg 4 specs. second of all, mpeg4 (.mp4) can not contain mp3 audio. It can use AAC, or Ac3 audio. You will have to convert using a program like handbrake to convert the video to a proper mpeg4 specs and the audio to AAC. You will loose some video/audio quality, But if you let handbrake use it default settings, the loss wont be much. Also the file size will be different. Possibly larger or smaller. Depends on how handbrake encodes the video as it tries to keep quality, and not file size.
     
  3. Makosuke thread starter macrumors 603

    Joined:
    Aug 15, 2001
    Location:
    The Cool Part of CA, USA
    #3
    I guess I was under the mistaken impression that while most MP4 players expect AAC audio the MPEG4 container spec allowed MPEG1 layer I through III audio streams.

    Regardless, converting the audio obviously isn't a big deal, but I'm pretty sure that the video stream was encoded with x264, not DivX, and I don't believe there were any settings used that aren't in the Main (maybe even Baseline) profile (though I admit I haven't checked). I'd think it would be possible to use the raw h264 video stream without transcoding, so long as the remuxing app knew how to appropriately prep the video stream and mux it for use in a valid MP4.

    Am I wrong about that? If so, I'd really appreciate it if you happen to have a tech document you could point me to that explains it, as I'd like to understand the technical details about what the format requires.
     
  4. dhd macrumors member

    dhd

    Joined:
    Dec 12, 2007
    Location:
    Hamster-Dam
    #4
    Hi there,

    Try with MPEG Streamclip, open the avi in question and save as mp4, if it doesn't work, save each stream as .mov and with Qt Pro make a "new" movie out of those .mov streams and try again to save as mp4.

    Good luck!!!
     

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