avi resized is bigger than the original?

Discussion in 'MPEG-1 and MPEG-2 encoding (AVI to DVD)' started by Metallo, Nov 12, 2005.

  1. Metallo

    Metallo Member

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    Hi,

    I've got several movie clips (from my camera) which are originally sized as 320 x 240.
    I have used the Resize filter and created a job process in VirtualDub to change them to 256 x 192.

    What I do not understand is why the original file is, say 3.777 KB and the resized one becomes 52.386 KB

    This is a problem for me because when I upload them to create a DVD, they do take much more space.

    What's the reason?
    How can I get an .avi file with the same size?

    Thanks
    Alex
     
  2. vurbal

    vurbal Administrator Staff Member

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    When you resize you're re-encoding. Unless you're applying some compression when you do that you'll end up with a much bigger file than what you started with. Since you say you're creating a DVD I don't understand why you're resizing to 256x192 anyway. That's not a legal DVD resolution so you're adding another step that will reduce quality without getting you any closer to your final format.
     
  3. Metallo

    Metallo Member

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    Hi,
    You do not understand and you are right, because I forgot to mention that 256 x 192 is the real movie size, but I do expand it by framing at 352 x 288, making it DVD compliant.
    When the quality is so poor, a smaller image improves the view on TV.

    Regards
    Alex
     
  4. vurbal

    vurbal Administrator Staff Member

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    Okay, that makes more sense. At any rate, as long as you're re-encoding you're going to get quality loss and end up with a different filesize no matter what. The size at this stage really has nothing to do with the size of the MPEG you're encoding afterwards for the DVD. That's a function of the compression format being used. As I said previously you're probably not compressing at all when you're resizing with VirtualDub. If you want to keep the same quality you're getting now you don't want to compress any more than necessary. You could use a codec like HuffYUV which only applies colorspace compression, but shouldn't give you a noticeable difference in quality.

    I can't stress enough though that the filesize of your final MPEG has nothing to do with the filesize you're getting out of VirtualDub. If you want a smaller MPEG you simply need to set your MPEG encoder to make a smaller file.
     
  5. Minion

    Minion Senior member

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    Also the Size of the AVI file has absolutly no effect on how big it will be after you convert it to DVD..

    The AVI file could be 100mb or 1000mb as long as they were the Same Length and they were both encoded at the same Bitrate they would end up the same size....

    Cheers
     
  6. Metallo

    Metallo Member

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    Hi,

    But when I upload them in, say, MemoriesOnTV, if you load an avi of 3 MB or a resized of 60 MB, it should make a difference in terms of space taken on the DVD, before convertion happens, or not??

    Alex
     
  7. vurbal

    vurbal Administrator Staff Member

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    You've lost me there. The AVI doesn't take any space on the DVD. The VOB file takes up an amount of space determined by the size of the MPEG video and audio streams plus muxing overhead plus a few pieces of information specific to VOB files. If the MPEG video is encoded at a low bitrate the VOB size will be small. If it's recorded at a higher bitrate the VOB size will be bigger. That's the only variable there is when it comes to size.
     
  8. Metallo

    Metallo Member

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    Hi,

    So, the indication you get when uploading the files in the program before converting them is only a "best estimate".
    Nonetheless, if the estimates says that you have uplodaed files for 5GB, the DVD won't burn.

    Alex
     
  9. vurbal

    vurbal Administrator Staff Member

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    It sounds like you're using an all-in-one type program that doesn't give you any control over the MPEG encoder settings. What program(s) are you using to create the DVD?
     
    Last edited: Nov 13, 2005

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