Originally posted by Arcade:
The reason we haven't seen Dolby True HD or DTS HD audio is the huge disc capacity required.
As of yet, there are no 7 channel mixes, only 5 channel mixes. There is also no audio above 24/48K.
Using Dolby TrueHD + a legacy DD track at 640K isn't as bad as I believe you're making it out to be. Let's assume worst case, and the Average bit rate is 4Mbits/second for TrueHD + the 640K. And for a two hour movie. Note that the legacy Dolby Digital track is required for Blu-ray (not for HD-DVD).
We can calculate storage by taking the Average Bit Rate and multiplying it out over the time period.
This would be:
4,000,000 + 640000 or 4,640,000 bits/second.
4,640,000 bits/second / 8 (bit/byte) = 580,000 Bytes/second for audio
580,000 Bytes / second * 7200 Bytes for the movie = 4,176,000,000 bytes for the film's soundtrack.
Everything is base 10 for disc storage instead of based on binary K (ie 1000 vs 1024).
This cleans up to 4.176 GB.
Disc capacity is 25GB so our percentage allocation is:
4.176 / 25 or 16.7% for audio (with lossless).
This is for a single layer blu-ray. It is half this for double layer. This leaves you with an available average bit rate value of 23.14 Mbits/second for video on a single layer disc. You aren't going to encode at that high of a rate, especially if you're smart enough to use an advanced codec.
For double layer HD-DVD you could scratch the legacy Dolby track if you wanted, but I'm going to be lazy and not recalculate the numbers.
4.176 / 30 or 13.9% for audio (with lossless).
Your average bit rate for this becomes 28.70 Mbits/second. See above about this.
I don't consider either of these unreasonable, especially when you use advanced codecs for video.
If you have numbers that disagree with mine, feel free to post them.
Cheers,
Google Search
|
Meridian Systems
|
Meridian Streaming
|
Restaurant
|
WiKi
|
Duncan's Meridian Info
|
Board Rules
|
Restaurant Rules
