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Speeding up playback rate of an xvid .avi by a percentage?

Discussion in 'Other video questions' started by n_black, Sep 1, 2008.

  1. n_black

    n_black Member

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    Hey all. I've got a couple of video files I need to speed up. The DVDs they were ripped from (the Reboot movies if you're familiar) were improperly encoded by the releaser, and as a result playback was reduced by 4% speed. I order to correct this in the video files, I need to increase playback speed of both audio and video by 4.28% (actually 4.27(repeating), but you can't put a repeating number into most programs).

    I'm hoping there's a way to do this speedup without actually reencoding the video. If there's not, what is the best way to speed up the video and recompress it with minimal quality loss?
     
  2. davexnet

    davexnet Active member

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    Are you talking about the 4% PAL speedup Vs. NTSC?
    Are you trying to go from 23.976 frame rate > 25
    (or vice versa)
     
  3. n_black

    n_black Member

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    It doesn't much matter. The end result is that I have two xvid files on my computer that play back at 96% of the speed they should, and to play at the normal speed, I'd have to increase their current speed by 4.28%

    If you really need to know the reason, it's because the company that made the DVDs these were ripped from messed up and encoded the 25fps source as though it were 24fps. There's more info here:http://en.wikipedia.org/wiki/ReBoot#VHS_and_DVD_release

    All I want to do, though, is increase the playback speed of an AVI and its sound by 4.27%.
     
  4. attar

    attar Senior member

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    You can change the frame rate in VirtualDub by adding 4.28% to the current rate and saving the file.
    The video would play faster, but the audio would be async.
    For the audio to match, it would have to be demuxed as a wav, loaded into the likes of Audacity and the tempo tool used to match the audio length to the new video length and saved as a new wav file, then the new audio would be loaded into Virtualdub and saved with the new video.

    It's covered here.
    http://www.hello-online.org/lofiversion/index.php/t4867.html
    Good luck.
     
  5. n_black

    n_black Member

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    Thanks!
     
  6. n_black

    n_black Member

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    I've got a new problem. I also need to resize to 16:9 (whoever encoded it forgot to correct for the aspect ratio), and keep it compressed. When I "save as avi" in virtualdub, it gives me an error about compressing to xvid:

    First it says "statsfile no found!"
    and then it says "Cannot start vdeo conversion: the operation is not supported (error code -1)"
     
  7. attar

    attar Senior member

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    I'm not sure why it cannot save the file - since the video is being saved as 'direct stream copy' - if it can load it it should save it unless you are using a filter to modify it..
    Use Gspot to identify the type of video, which codec it uses and if the codec is installed on the PC.



    [​IMG][/img]
     
  8. n_black

    n_black Member

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    I am using the resize filter to make it 16:9. Right now it's at some random incorrect size.
     
  9. attar

    attar Senior member

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    So your selecting 'Full processing mode', choosing a compressor and the compressor (codec) is installed?
     
  10. n_black

    n_black Member

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    Yep. I'm choosing the most current xvid, but it can't seem to deal with resizing. If I disable resizing and just do the framerate increase it works fine, but then there's no point in recompressing. Is there some other way to resize to 16:9 after I deal with the audio issues?
     
  11. n_black

    n_black Member

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    Wait, I think I figured it out. XVID will only encode things in ARs that are multiples of 2, so I specified an absolute resolution of 854x480 rather than simply telling vdub "16x9".
     
  12. n_black

    n_black Member

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    Okay, after a lot of square dancing and a couple virgin sacrifices I now have a video file that is the proper AR at the proper speed.

    But it's 4.2 gigabytes. I can't get Virtualdub or Virtualdubmod to do a two-pass encode with XVid (it still complains about a missing statsfile). How do I get this filesize down?
     
  13. attar

    attar Senior member

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    Are you compressing the audio.
     
  14. n_black

    n_black Member

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    Yes. The problem is that vdub won't do two passes for compression, so the filesize is pretty nonoptimal.
     
  15. davexnet

    davexnet Active member

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    The stats file is created during the first pass.
    Are you sure you're not selecting 2nd pass before you did the first
    pass?
     
  16. n_black

    n_black Member

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    D'oh. That's exactly what I was doing! Once I do the first pass, do I do the second pass from the save file?
     
  17. davexnet

    davexnet Active member

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    I don't think you need to do anything special.
    Just set 2nd pass in the xvid options,
    and file/save avi. (if the 1st pass created an avi, it
    is useless and can be deleted)

    The stats file created from the 1st pass is on your HD
    somewhere and will be used in the 2nd pass to allocate
    the bit rate.
     

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