Re:
> I am creating a DVD from several separate mpeg2 files.
> Should I expect the quality of the end DVD to be less than that of the
> MPEG2 files?
Yes - IF the MPEG2 files are large enough such that when they are combined
the whole collection will need more compression to fit on the disc, and
especially if you are putting the on the DVD via some sort of software that
decides the compression level (quality) of the final file going on that DVD.
> And should it get worse as the MPEG files become more numerous?
Yes. The longer the running time of the video files, the more they would
need to be compressed to fit on one DVD.
> I use Corel VideoStudio Pro X2.
I'm not familiar with it. Maybe someone who is can provide specifics of how
it exports MPEG2 files.
> I know from experience that if I combine / render multiple MPEG2 files
> into a new, larger MPEG2 file, that the result is a poorer quality
> MPEG2 than the starting material. I don't know that the same thing
> happens when you create a DVD.
I'm assuming your video editing and DVD authoring software runs the MPEG2
files out according to some type of preset targetting DVD delivery. It may
be automating the amount of compression in relation to DVD file capacity and
not necessarily according to, for example, making high image quality the
main priority no matter what the resulting file size will be.
> My understanding is that DVD's are MPEG2 in the core... but I am
> hoping that the DVD format somehow allows the indidual files to remain
> separate... thus not accumulating error when they are "combined" or
> some such.
The DVD format can only fit a certain amount of video on a disc at any given
degree of compression. As you try to fit more clips onto one DVD, many DVD
authoring apps will, obviously, default to a lower quality (higher
compression) level for the combined output. This may affect just exporting
any MPEG2 video, intended for DVD or not, because the software might be
guessing the output file _has to_ fit onto a DVD.
Steve Bennett
www.ifmpstudios.com
|
