What is multichannel?

Discussion in 'FRAPS General Discussion, Guides, and Tutorials' started by DropTheBass, Mar 31, 2012.

  1. I just want to know what multichannel is on Fraps, it is the audio part if you wanted to know, but what is it?
  2. Thalmor Wizard

    Thalmor Wizard Moderator Staff Member Site Contributor

    I assume it's similar to Dolby Digital, but I honestly don't know. raffriff will be able to answer this when he comes online.
  3. I have saw him on the forums, he is like a fraps pro :p.
  4. raffriff

    raffriff Moderator Staff Member Site Contributor

    Well, I'm still on XP and I don't have the multichannel option (I know, I know...soon.) I'll take a guess at what it is and what it means, and maybe you can verify whether my guess is correct...

    TL;DR multichannel = surround sound

    A Fraps AVI video file has two "Streams": Video and Audio. The Audio stream can have more than one "channel". If the video is "stereo", there are two Channels, L and R. If a video is "multichannel" it means it has more than the two stereo channels. For example 5.1 audio has Front Left, Front Right, Front Center, Left Back, Left Right and "Low Frequency Effects" aka Subwoofer.​

    If I open a sample video with 5.1 audio in Media Player Classic Home Cinema, and click File, Properties, MediaInfo, I see:​
    Channel(s) : 6 channels
    Channel positions : Front: L C R, Back: L R, LFE

    But if I open a "normal" Fraps AVI file, I see:​
    Channel(s) : 2 channels

    I think the channel layout is *probably* set in Audio Control Panel when you specify your speaker layout - stereo, quad, 5.1, 7.1 or whatever. Or maybe "multichannel" is always 5.1, I don't know. That's what you need to check for yourself.​

    Then the next issue is editing multichannel, and after that, how does YouTube handle it...
    EDIT - it seems multichannel is not supported in Premiere, and it seems YouTube mixes multichannel down to stereo...

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