AVS Forum banner

1 - 14 of 14 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 ·
I have noticed that most japanese BluRays with anime have stereo PCM track EVEN if its a recent movie with DTS-MA 5.1 track. Why do they bother with uncompressed stereo if they have uncompressed surround? Is DTS-MA (or even DTS core) worst in stereo downmix or is it legacy thing with AVR with Pro Logic and DD only with no DTS decoder?
 

·
Banned
Joined
·
14,420 Posts

Quote:
Originally Posted by R4Zi3L  /t/1523583/stereo-pcm-on-blurays#post_24510675


I have noticed that most japanese BluRays with anime have stereo PCM track EVEN if its a recent movie with DTS-MA 5.1 track. Why do they bother with uncompressed stereo if they have uncompressed surround? Is DTS-MA (or even DTS core) worst in stereo downmix or is it legacy thing with AVR with Pro Logic and DD only with no DTS decoder?

Stereo and multichannel tracks if well-made will be significantly different from each other and there may well be be no algorithmic or automated way to transform one into the other. Optimally, they will be hand-crafted separately.


This is pretty obvious for stereo->multichannel, but it can be equally true for multichannel->stereo. Both kinds of track need to be on a quality production.
 

·
Banned
Joined
·
18,829 Posts

Quote:
Originally Posted by R4Zi3L  /t/1523583/stereo-pcm-on-blurays#post_24510675


I have noticed that most japanese BluRays with anime have stereo PCM track EVEN if its a recent movie with DTS-MA 5.1 track. Why do they bother with uncompressed stereo if they have uncompressed surround? Is DTS-MA (or even DTS core) worst in stereo downmix or is it legacy thing with AVR with Pro Logic and DD only with no DTS decoder?
DTS HD MA has the metadata and ability to downmix to 2.0. To do that though, you need to recreate the 2.0 mix from your multi-channel mix. I am not into Anime but for theatrical releases, that usually requires talent approval. Likely the stereo mix they already have was created for TV and such and is pre-approved so they rather use that than to create yet another one from the downmix.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
Well i tried both tracks, and i really didnt like how stereo sounded comprered to surround, so i dont know that the big thing is about stereo only track... oh well, i think that if they have a space on disc they can throw in it anyway...
 

·
Banned
Joined
·
18,829 Posts
Of course surround sounds different and better than stereo. Or do you mean you down converted the surround to stereo and liked that more?
 

·
Registered
Joined
·
1,445 Posts

Quote:
Originally Posted by R4Zi3L  /t/1523583/stereo-pcm-on-blurays/0_100#post_24511752


Well i tried both tracks, and i really didnt like how stereo sounded comprered to surround, so i dont know that the big thing is about stereo only track... oh well, i think that if they have a space on disc they can throw in it anyway...
 

It could be useful for someone who has a two channel system instead of a surround system.  For many years, I used a two channel system with my TV and movies, because that is what I had for music and did not have the money to buy a decent surround system (which used to cost more than it does now).  Most likely, if both are well-made, one will tend to prefer the surround mix on a surround system.  On the other hand, if one is bungled horribly, and the other one is not, then the other one will be best.  But I doubt you will run into very many examples of that.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #7 ·

Quote:
Originally Posted by amirm  /t/1523583/stereo-pcm-on-blurays#post_24511818


Of course surround sounds different and better than stereo. Or do you mean you down converted the surround to stereo and liked that more?
Yes i meant 2 channels vs 6 channels... I also trayed downmix DTS-MA with headphones and switching between them... PCM was less pounchy i guess and voice more blended with rest.... typical for DTS i think... dunno maybe it have its rights to be seperate...
 

·
Registered
Joined
·
8,441 Posts

Quote:
Originally Posted by R4Zi3L  /t/1523583/stereo-pcm-on-blurays/0_60#post_24510675


....uncompressed surround?...

Just a little correction. DTS-MA is compressed. The word you were looking for is lossless.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #9 ·
Yeah i know... PCM is also a form of compression for analog signal.... its just digital representation...
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #11 ·
PCM is codec like everything else... is it DPCM, LPCM, ADPCM..... with its bitrate (transport stream dependent), algorithms and so on..... its just isnt very efficient (low processing power need) so it can be very easy compressed (which require some processing power that wasnt available in 1980s) like either other digital data....
 

·
Registered
Joined
·
8,987 Posts
^^ You seem to be confusing two different processes. PCM (Pulse Code Modulation) is a method of digitally representing an analog signal. Codec (COmpression DECompression) is a method of reducing the size of a digital data file for storage and transmission.


PCM is the fundamental type of digital audio used in entertainment. It's used on CDs. It's how movies are mastered. And it's the digital format that players and receivers process to produce sound. But, multichannel PCM soundtracks are quite large. So, studios use codecs such as DD 5.1, DTS, and their lossless cousins to save space on discs. PCM is fed into an encoder to reduce the size and then is decoded to expand it back into PCM.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #13 ·
Now you are confusing codec with compressor. Lossless "codecs" act like zip compressors, they docompress on the fly the archive. Yes, TrueHD contains stream encoded as PCM but is compressed like FLAC for example. Industry could fit double the PCM encoded music on CD. Or same lenght but with highier quality like 48/24bit) DTS-MA contain lossy core with difference data from original PCM encoded file.

You can use music from MP3 file in movie, encoded it in PCM, a then compressed it with TrueHD.... It still "uncompressed"?
 

·
Registered
Joined
·
8,987 Posts
What? Codec vs. compressor. I have no idea what that means.


As for the quality of PCM, it can be very high or very low. Depends on the source. But, it does not involve data compression, which is what several posters here have been trying to explain to you.
 
1 - 14 of 14 Posts
Top