Originally Posted by Theron2
i read the reason to that yesterday but can´t find the link right now
HD-DVD has less space than Bluray so they limit the bitrate of the Dolby True HD track to max 3 mbit instead of max 6 mbit on Bluray, so much for the better format discussion
Actually I believe DTHD limits are the same on both formats, those being 8 channels an 18Mbps. Further, DTHD is a lossless codec, you can't just reduce the bitrate, or lower the quality. If you could it wouldn't be lossless. You compress it and it is what it is.
And one more thing, as far as max audio bitrates go, I agree, you're probably thinking of DD+ which has a max bitrate of 3.0Mbps on HD DVD and 1.7Mbps on Blu-ray.
the question remains if studios would or are producing different? True HD Tracks for each HD format? i don´t believe that, another question is: can the HD-DVD True HD track really be lossless then...in all movies?
Dolby TrueHD is a lossless codec, it outputs what you input to it. End of story.
for example Transformers is a pretty long movie and i believe they had to reduce the bitrate to still provide "lossless" Sound...but is it really lossless if you have to reduce the bitrate due to space limitations?
Transformers has a DD+ track, not a DTHD track.
my understanding of lossless is: you pack it as good as your codec is able to squeeze the data but you don´t leave data out...
Lossless compression just repackages the same data more efficiently (smaller file size, lower bitrate than the source). Just like a zip file makes a file smaller.
...which is exactly the case if you reduce the bitrate, either the sound needs that much space and bitrate and is lossless...or you reduce the bitrate and therefore the filesize but then it´s not lossless anymore
You simply can't do that with lossless, you can't "tune" the bitrate with a lossless codec like you can with a lossy one. The only thing you can do with a lossless codec is tweak how hard it tries to pack the audio, but you still don't have any direct control over the final bitrate. It is what it is.
If you need something to be smaller than the lossless codec will make it, you have to switch to another codec.