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5.1 ch Audio with wrong channel distribution, Center mixed with L & R while lacking actual center info.
Seedmanc
post Dec 23 2011, 19:09
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I have various Blu-Ray rips of live concerts with 5.1ch audio.
Recently I noticed that in most of them audio data seem to be improperly assigned to different channels.
Correct me if I am wrong, but this is how I see the "proper" distribution of audio among channels:
  • Left and Right should contain music being played on stage
  • Center is Vocals and some Solo instruments, like guitar
  • Side L/R are hall noise and echo, and LFE is bass.

Assuming that is correct, here is audio sample with such distribution
http://www.hydrogenaudio.org/forums/index....ost&id=6810
and its waveform, as seen in Audacity
http://www.hydrogenaudio.org/forums/index....ost&id=6814
The problem is, however, that out of all concerts I have, only one has such audio. All the others have Vocals mixed with Left & Right, as in 2.0 audiotrack, while the actual Center channel contains quite weak and distorted signal, as if it was "rear center" or something. Other channels are intact, though.
Same song, other BD:
http://www.hydrogenaudio.org/forums/index....ost&id=6813
http://www.hydrogenaudio.org/forums/index....ost&id=6815
I thought it could've been ripper's mistake, but then I obtained BD-ISO, and it has the same problem.
Unfortunately I don't have 5.1 sound system, so I can't judge how it should sound, but I suppose the first one being better anyway.

Therefore my questions are:
  1. Is such "wrong" distribution really common for blu-rays and what is considered to be "proper"?
  2. Is there any way to reconstruct proper distribution, so that I will have vocal-less Left and Right?

The usual method of cutting common between L&R like in any stereo audio doesn't fit quality requirements, so I thought maybe I can use existing center channel, even though it sounds wrong. The reason I need them is that I want to create instrumental collection of songs being performed on stage, by extracting music-only L&R. I already successfully did it for songs from first BD.
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musicreo
post Dec 24 2011, 12:15
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You don't know if the concerts are recorded in 5.1 or later mixed to 5.1. Also there is no rule that vocals have to be mixed to the center channel and if you don't have a separately vocal track it is hard to mix it only to the center.

You can't reconstruct the 5.1 track, so that you have vocal-less Left and Right without decreasing the sound.

QUOTE (Seedmanc @ Dec 23 2011, 19:09) *
Unfortunately I don't have 5.1 sound system, so I can't judge how it should sound, but I suppose the first one being better anyway.


You can use your Headphones with foobar and Dolby Headphone to get an impression how it sounds.

This post has been edited by musicreo: Dec 24 2011, 12:18
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bigshot
post May 10 2013, 19:13
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In rock music, all bets are off. The rear channels on Orbison's Black and White Night have background vocals for some screwy reason. For classical music, it is much more standardized. But there are still a few mistakes here and there. For instance, Mehta's Valencia recording of Wagner's Das Rhinegold has the left and right channels reversed. I don't believe it's been corrected since first release either.
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ktf
post May 10 2013, 20:45
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QUOTE (bigshot @ May 10 2013, 20:13) *
...

Did you notice this thread is more than 1 year old? It's probably not longer relevant.


--------------------
Music: sounds arranged such that they construct feelings.
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bigshot
post May 11 2013, 20:29
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Incorrect channel distribution doesn't occur any more? I cited a bluray that was released recently that has a problem with that.

Boom! Relevance.
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