DVD authoring question

Discussion in 'Computers' started by Patrick Sun, Dec 10, 2003.

  1. Patrick Sun

    Patrick Sun Studio Mogul

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    Someone asked me why authoring a DVD would increase the size of the file before it's prepped for being burnt to a blank DVD.

    He got a 700MB MPEG2 file, and when he used a basic DVD authoring program, I think SonicDVD, to convert it for DVD use, and the resultant VOB files was around 2GB in size. Does anyone know why this happens? The length of the video was over an hour from the original MPEG2 file.
     
  2. Rob Gillespie

    Rob Gillespie Producer

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    It might be a safety feature to ensure compatibility with standalone players. Not sure what the minimum size is, but I've heard of some players having problems with small files.
     
  3. Patrick Sun

    Patrick Sun Studio Mogul

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    That could be it. Hopefully one of these days I'll be up and running myself and can see if I can duplicate this occurence.
     
  4. John_Berger

    John_Berger Cinematographer

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    I once tried to create a test DVD with only a 50 MB MPEG-2 file. The DVD software (Sonic DVDit! PE, I believe) gave me a message that to ensure compliance with DVD specifications, the resulting size of the final project had to be something like 1 GB! [​IMG] Your situation probably is identical to that.

    Audio was also converted from whatever compressed format it was in to PCM since the software program (I'm assuming that you meant Sonic MyDVD) does not handle Dolby Digital or MPEG audio that I know of. (Of course, I haven't used the newest version, so I could be wrong on that.)
     
  5. DaveGTP

    DaveGTP Cinematographer

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    I think the audio comments are most likely. It could also, however, be tinkering with the resolution or bitrate of the file - the resolution of DVD mpeg-2 is fixed at a certain level.
     
  6. John_Berger

    John_Berger Cinematographer

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  7. DaveGTP

    DaveGTP Cinematographer

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    Wouldn't upscaling the resolution and writing that to a file create a bigger file? (Even if it's not creating information).
     
  8. Ken Chan

    Ken Chan Producer

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    If the original MPEG was not a DVD-compliant resolution, then it would have to reencode the video to (most likely) 720x480. And if that's bigger than the original, then yes, the file would end up bigger. But unless it was the size of a postage stamp, that doesn't explain how a 50MB file grows to 1GB.

    The bottom of this page mentions something about a 1 GB minimum.

    //Ken
     

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