virtualdub not deleting selection

Discussion in 'DivX / XviD' started by sheik482, Dec 1, 2005.

  1. sheik482

    sheik482 Member

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    I am trying to delete the first 120 frames of a divx file. I cut out the part and everything looks fine, then when I save the avi the resulting file still has the 120 frames. Anyone have any idea why it is doing this? I have it set to direct streaming of audio/video.
     
  2. sheik482

    sheik482 Member

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    I think it has something to do with deleting the keyframe at frame 0. So how would you go about making frame 121 a key frame?
     
  3. celtic_d

    celtic_d Regular member

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    That would require that you re-encode from frame 121 until the next available keyframe that is already present, say 250.
     
  4. aldaco12

    aldaco12 Active member

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    I would try to do this thing: not deleting frames, but saving a second AVI from frame F to frame E where F is the fists keyframe larger then the segment you want to delete, and E is the ending frame.

    You just have to set Video___Direct Stream Copy when you open your file in VirtualDub, and select Video___Select Range to insert F and E (avoid readinmg the ms, just look at the second half-screen, the one showing the frames).
    Be sure that all optins are checked.
     
  5. Lardzor

    Lardzor Member

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    Just my 2 cents.

    I do recall reading something about clips haveing to start with a keyframe, but you can truncate them anywere at the end. The beginning has to be on a keyfram.

    FYI, A keyframe is a frame that has ALL the info needed to construct a complete frame. Sure it's compressed, but it doesn't rely on data from the previous frame. That's why MPG-4 is so good at compression. It mainly stores only the changes from one frame to another. If the picture only changes a few pixels, it only stores the few pixes worth of data it needs to modify. The downside is that if you don't have the data from the previous frame, you don't have enough info to construct the current frame. You have to start with a keyframe because without the data from the previous frame, you don't have enough info to make a complete frame. It's also why when you seek through a video file with keyframes, you can only seek to a keyframe.
     

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