Dolby Digital in the Cinema VS Home Movies

[chriharr]

A question that has been puzzling me for ages and I can't seem to find the answer

Is Dolby Digital in the cinema the same as what we get at home, are the bit rates in the cinema really as low as 640Kbps or is it like Dolby Digital Plus where you get like 1.5Mbps right up to 3.5Mbps that was available on HD-DVD back when that was an active format.

I always thought that Cinemas had to have uncompressed sound, If Dolby Tru-HD is better than what you get at your local cinema than that would be weird

Is Dolby Digital at the cinema AC-3 at all or is that just a codec for at home?



Can someone please tell me if theres a difference for the cinema and home video

[DonRSD]

good thread.

[DeadDog]

I'm not postive, but I do beleive that the cinema does use uncompressed sound. I'd assume PCM but it could be DTS-HD or Dolby TrueHD.

HD-DVD had better sound than DVD's but didn't have the capability of the higher audio bitrates blu-ray can handle. So from what I understand Blu-ray is the same audio quality as the cinema (although individual setups could make that either better or worse than the theater).

Someone correct me if I'm wrong .

[cembros]

dolby true hd and every other lossless and uncompressed format is the same as what you hear in the theater. Dolby digital and dolby digital plus are lossly compressed versions of the films master and are inferior to what you hear in the theater

[cembros]

as for the format that the theaters use, its usually either dolby, dts or sdds

[Arriaga2]

Actually Dolby Digital theatrical is encoded at 320 kbps, so it's even more compressed than the normal SD DVD bit rates (384 & 448 kbps). DTS theatrical is normally 1.5 mbps on the CD ROMs(same as full bit rate DTS for SD DVD & DTS-MA "core" on Blu). Not exactly sure what the bit rate is for SDDS, but I know it's higher than DD's.

[cembros]

yes it looks like i was wrong, http://en.wikipedia.org/wiki/DTS_Coherent_Acoustics

this explains it all

[chriharr]

I know that Cinemas use sophisticated pre-amps, processors & matrixers etc.

But for some reason movies at the cinema still sound good and superior to any home cinema i've experienced.

I know the Imax used 6 channel 16bit uncompressed sound CD Quality since the 90's which was encoded at 1411Kbps for every two channels.

SDDS is dead in most countries anyway, so I don't think it matters SDDS uses ATRAC codec which was developed by Sony and was mainly used for compressing music on Mini-disc players and Sony included the codec for use on the PS3.