If trueHD can handle bitrates of 18mbs why they so low

[Stu123]

If trueHD can handle bitrates of 18mbs why they so low hovering around 2.5 to 3 mbps

[Afrobean]

Originally Posted by stubiedoo

If trueHD can handle bitrates of 18mbs why they so low hovering around 2.5 to 3 mbps

Because that's all it requires to accurately and losslessly reproduce the source PCM.

Asking for higher bitrates on a lossless compression is ridiculous. LOWER bitrates on lossless compressions are better.

[ryoohki]

It's just like asking you to send my you're EXCEL document. You can ZIP it a HIGH for 120kbytes, or LOW for 1.2meg of size, both will be the same once extracted but why loose 1.1meg over it?

[Stereo24192]

Originally Posted by Afrobean

Because that's all it requires to accurately and losslessly reproduce the source PCM.

And because in movie productions that source PCM still is 24 bit/48kHz in most cases.

There are a few exceptions:
The bitrate on Baraka
https://www.blu-ray.com/movies/Baraka-Blu-ray/1055/
and Akira
https://www.blu-ray.com/movies/Akira-Blu-ray/1872/
is considerably higher because of the higher sampling frequency
of the source PCM master.
Baraka: 5.1 24bit/96kHz
Akira: 5.1 24bit/192kHz

On music Blu-rays 96kHz recordings are far more common.
In my mind the fact that Hollywood still refuse to go higher than 48kHz
is a big dissapointment. But that's another issue.

[turboLAZER]

Originally Posted by stubiedoo

If trueHD can handle bitrates of 18mbs why they so low hovering around 2.5 to 3 mbps

18mbps might be necessary if the source material is a 7.1 24bit/192kHz PCM
, but almost all source material is 5.1 16bit or 24bit/48kHz PCM