How to unfold a 2.0 stereo mix to its original 4.0 channels

[maldon]

Yesterday, I saw some information on blu-ray.com that caught my attention: Bad Day at Black Rock was released to theaters in both mono and four-track stereo. The latter has been used for Blu-ray, with the four tracks folded down into a 2.0 mix encoded in lossless DTS-HD MA 2.0.

Is there any software that will open a stereo file to see all the discrete channels? I want to “unfold” or “De-Matrix” the mix back to its original four LCRS channels.

[tebasuna51]

Nope.

If the track was AC3 maybe a Dolby Prologic mix can be expected, but with DTS-MA we can't expect it.
DTS-MA have the layout LCRS, if was downmixed maybe is because the surround channel was near empty.

[maldon]

Nope.

If the track was AC3 maybe a Dolby Prologic mix can be expected, but with DTS-MA we can't expect it.
DTS-MA have the layout LCRS, if was downmixed maybe is because the surround channel was near empty.

Thanks a lot, tebasuna51, but I don't understand what you mean by “If the track was AC3 maybe a Dolby Prologic mix can be expected, but with DTS-MA we can't expect it”.

AFAIK, all 4 channels are there, it's like a Dolby Stereo mix (424). So, I guess we must be able to hear the four channels with a home cinema with Dolby ProLogic: Left, Center, Right and Surround, even if the mono surround channel is almost empty (I think it was common in Cinemascope films of that era). I want to get 4 mono channels from that 2.0 stereo track and export them like LPCM 4.0 or DTS-HDMA 4.0.

I don't understand why they didn't encode it as 4 track discrete. They rarely include such a track, there are a few exceptions such as “Garden of Evil” (also Cinemascope): the also included DTS-HD Master Audio 4.0 mix (recreating the four track stereo presentation of the original theatrical exhibition). (blu-ray.com)

[junh1024]

Nope.

If the track was AC3 maybe a Dolby Prologic mix can be expected, but with DTS-MA we can't expect it.
DTS-MA have the layout LCRS, if was downmixed maybe is because the surround channel was near empty.

Matrixed surround in stereo can be stored in any medium, analog & digital, and any codec. Since it's regular stereo audio.



Is there any software that will open a stereo file to see all the discrete channels? I want to “unfold” or “De-Matrix” the mix back to its original four LCRS channels.

WHen surround is downmixed to stereo, it's generally impossible to recover the original channels as it's not discrete anymore - dimensions are lost. Please use any surround upmixer to increase the channels. Keep in mind upmixing algorithms are subject to changes & improvements over time.

https://i.imgur.com/0o7Rflf.png

[tebasuna51]

See also that thread LT+RT to surround, how? (https://forum.doom9.org/showthread.php?t=184161)

[maldon]

Thank you very much!!!!