On Mon, Nov 10, 2008 at 12:37:30PM +0000, Mark Rogers wrote:
Adam Bower wrote:
Then you have to take into account that most HD-DVD discs have much better audio soundtracks options than normal DVD soundtracks, so these will take up more space.
But a dual-layer DVD is 9GB so still using MPEG4 should be capable of fitting it all onto a single disk.
Dual layer dvd is more like 8.5GB, but the whole point of HD-DVD isn't to compress the crap out of everything so it looks crap. You could encode the video to fit on a single DVD but it would look rubbish, just because a particular codec *can* compress video so it is smaller doesn't mean it should be used to do so!
I think that the best you will see with like for like (quality wise) mpeg2 vs. mpeg4, that it would be half the file size for an mpeg4 encoded film compared to mpeg2. Given that the HD source already contains 5 times as much information in the first place compared to a DVD, let us play with some numbers.
Lets say that you have a decent DVD film with a film on that contains 6GB of data, with an HD-DVD because of the increase in resolution you will now have 5x6GB so you now have 30GB of data, you can encode that to half the size using mpeg4 before you will suffer a loss of quality, so you still need 15GB of space which won't fit on a DVD hence higher capacity systems are needed.
You also have to take into account that the video on a DVD is already compressed, that doesn't mean it actually looks good in the first place and couldn't have done with being a higher bitrate/quality but that wouldn't fit on the DVD so a compromise has already been made.
This is the point of HD-DVD/Blu-Ray that you don't have to compress the crap out of everything just to make it smaller so it fits on the disc. Some people appreciate quality and want it to look as much like the cinema as possible in their home theatre ;)
Oh, and you should have got an HD-DVD player when they were £70 with 5 free films included ;)
Adam