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Provo Video Compression

Discussion in 'SouthWest Region Discussion' started by Toran-Kal, Nov 9, 2001.

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  1. Toran-Kal

    Toran-Kal Jedi Youngling star 2

    Registered:
    Apr 23, 2001
    Ok I thought that I might ask this question in this forum because you guys will be a lot nicer about questions that are asked all the time. :)

    I'm trying to compress a short video clip. I have access to Premiere which also comes with Cleaner EZ. I just don't know what settings are best for the compression.

    A good example is the Star Wars Breathing teaser. Their movie is 640 X 272 and they were able to compress it down to 12 MB. The movie I'm trying to compress is only 320 X 240 and I can get it down to about 30 MB and have it still look good. So what am I doing wrong?

    Does anyone know of any settings or maybe good websites that will help with this?

    Sorry this was such a long post. I hope it all makes sense.

    Thanks
     
  2. Handyman

    Handyman Jedi Padawan star 4

    Registered:
    May 19, 2000
    Greetings Toran-Kal,

    Which Codecs are you using for Video and Audio?

    My best results with Quicktime compression come with Sorrenson 3 for Video and MP3 for audio.

    Later,
     
  3. Toran-Kal

    Toran-Kal Jedi Youngling star 2

    Registered:
    Apr 23, 2001
    Sorensen 3 is what I've been experimenting with. But I just don't know what settings to use.
     
  4. andakin

    andakin Jedi Padawan star 4

    Registered:
    Dec 8, 2000
    make sure you use the keyframing setting. If you don't it's going to compress every frame.
     
  5. Toran-Kal

    Toran-Kal Jedi Youngling star 2

    Registered:
    Apr 23, 2001
    Yes I've been wondering what to do about the keyframe stuff. What exactly do keyframes in compression do? And what should I set it at?

    Thanks again
     
  6. Handyman

    Handyman Jedi Padawan star 4

    Registered:
    May 19, 2000
    Greetings Toran-Kal,

    A keyframe is a reference frame to remove redundant data from subsequent frames. In essence, the frame that follows a keyframe will only have to store data that differs from the key. This is a common technique that is used in all types of data compression.

    A video with little motion can get away with relatively few keyframes as there is not much difference in the picture frame to frame. In videos with alot of motion, the fewer keyframes you use will make the video smaller in size but have alot more motion trails or artifacts.

    Choosing an appropriate level of keyframing depends on the video and comes with experience. Play around with different levels of keyframes to see how it affects your video quality and byte size.

    Hope this helps,
     
  7. spoo

    spoo Jedi Padawan star 4

    Registered:
    Mar 16, 2001
    Doesn't it also make sure that your audio & video are in synch? That's what I thought it did...
     
  8. Handyman

    Handyman Jedi Padawan star 4

    Registered:
    May 19, 2000
    Greetings Spoo,

    The term Keyframe has alot of uses depending on the context. I'm talking about keyframes for video compression.

    Keyframes are also used to keep audio in sync, but not the SAME frames used for video compression.

    The term Keyframes is also used in animation, both 3D and traditional.

    Hope this helps,
     
  9. Toran-Kal

    Toran-Kal Jedi Youngling star 2

    Registered:
    Apr 23, 2001
    Ok then........ ?[face_plain]
    I guess all I can do is just experiment with everything huh?

    Thanks
     
  10. andakin

    andakin Jedi Padawan star 4

    Registered:
    Dec 8, 2000
    Not really. Start experimenting with a keyframe every 30 frames... then every 15... etc. and try to balance quality with size.
     
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