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[Trumpetguy]

I know there has been some debate in other threads about channel order, but I would like to get a fresh overview on how MC is mapping channels for the most widely used movie audio tracks. Is MC using this

http://en.wikipedia.org/wiki/Surround_sound#Channel_identification

or other channel orders?

One concern is how to deal with 6.1 audio tracks. In the new LotR bluray, the 6th track, which should be the rear channel appears in channel 7. This means that the side channels are sent to channel 5 and 6, which is my side channels (according to the wiring diagram in Wikipedia)... This is usually taken care of by using JRSS to mix up from 5.1 to 7.1.

Out of this two questions arises:
1) What happens with a 6.1 when applying JRSS to mix up to 7.1?
2) What is the 7.1 channel order when JRSS mixes it up from 5.1?

BTW - when using search engine to search for "6.1" I ended up having lots of hits on "1.6".

[Matt]

7.1 coming out of Media Center should always be:
L, R, C, SW, RL, RR, SL, SR

[Trumpetguy]

That applies both for original 7.1 audio track and JRSS upmixing from 5.1?

[Matt]

That applies both for original 7.1 audio track and JRSS upmixing from 5.1?

Yes.

I suppose the 7.1 original could have the incorrect channel order, but it would be a bug in the file or decoder.

[Trumpetguy]

Of course.

And then back to 6.1 - am I right to assume L, R, C, SW, SL, SR, Back center (or whatever correct abbrev is) ?

[Matt]

And then back to 6.1 - am I right to assume L, R, C, SW, SL, SR, Back center (or whatever correct abbrev is) ?

Exactly.

[Trumpetguy]

Right, that leads back to my original question. What happens then when feeding in a 6.1 track JRSS upmixes to 7.1? Is the 6th channel duplicated? And if so, is it balanced to take into account increased sound pressure from two speakers, and to which channels?

Will it be like this:
L, R, C, SW, RL, RR, SL, SR
where RL and RR are the sixth audio track somehow duplicated and attenuated (3 or 6dB)?
?

If not, I will be forced to re-wire my speakers when playing 6.1....

[Matt]

If you have a 7.1 setup, you should select 7.1 with JRSS mixing.  It'll do a good job with any format, 6.1 included.

More here:
http://wiki.jriver.com/index.php/Audio_Setup

[Trumpetguy]

If you have a 7.1 setup, you should select 7.1 with JRSS mixing.  It'll do a good job with any format, 6.1 included.

More here:
http://wiki.jriver.com/index.php/Audio_Setup

I trust you completely on that  . However, I have read the wiki pages before, but they contain little technical info, and I can not see that they answer what I am asking. I think they are quite relevant questions.

[Trumpetguy]

I just tried playing Lord of the Rings, the new extended bluray version, ripped to mkv with 6.1 flac audio. With JRSS mixing set to 7.1, it only plays back 7 channels, and leaves the 8th channel silent. The stream selection menu (right click onscreen menu) during playback tells me the audio renderer is receiving 7 channels, not 8.

This tells me that JRSS is not working according to intention, right? In particular, I would be worried (?) if the SR and SL channels still are played in channel 5&6 rather than 7&8.

EDIT: I will be trying with the original bluray disc tonight to see if there is any difference.

[Matt]

I just tried playing Lord of the Rings, the new extended bluray version, ripped to mkv with 6.1 flac audio. With JRSS mixing set to 7.1, it only plays back 7 channels, and leaves the 8th channel silent. The stream selection menu (right click onscreen menu) during playback tells me the audio renderer is receiving 7 channels, not 8.

The audio engine should receive 7 channels.

And then it should output 8 channels.  You can check the top of any DSP Studio plugin to see the current output format.  It'll say something like "Enabled and processing data with format x".

You can use the "Solo" buttons in DSP Studio > Room Correction to listen to each speaker.

[Trumpetguy]

I see the point with the audio engine in/out channels.

I have (digital) VU meters for each channel (Lynx provides a full software mixer with their DAC). Even at very high sound levels, I can see from the channel 8 VU meter that this channel is silent (not just inaudible, but no response even below -80dB). With any other movie, either native 7.1 or 5.1 mixed to 7.1, all channels are always showing something in the VUs, at least below the noise floor (around -60, maybe -70dB).

I will check this further to see if there  are something I have missed. Not unheard of...

[Matt]

Is there any way you could provide a small 7 channel sample?

It's also possible there's a bug, because I don't have any 7 channel sample files.

Thanks.

[Trumpetguy]

Is there any way you could provide a small 7 channel sample?

It's also possible there's a bug, because I don't have any 7 channel sample files.

Thanks.

If I knew how to I could 
I have several 7.1 (and a few 6.1) audio tracks as flac. These could be transcoded to pcm or wav, maybe using eac3to?. Is there a way to extract a limited part of this? I think sharing a full audio track would violate some copyright regulations.

[nwboater]

If I knew how to I could 
I have several 7.1 (and a few 6.1) audio tracks as flac. These could be transcoded to pcm or wav, maybe using eac3to?. Is there a way to extract a limited part of this? I think sharing a full audio track would violate some copyright regulations.

I've used the free program 'Audacity' in the past for extracting & combining tracks, but only with 2 channel. Don't know if it can handle multi channel. Try Googling for it - It's a really neat program.

Rod

[Trumpetguy]

I am leaving for three weeks offline summer holiday tomorrow and will not have the cahnce now to provide a sample. I did some tests, though, using Room Correction plugin mute function to test if 5.1 and 5.1 mixed to 7.1 where playing in the correct channels. They were. Goes for 7.1 native material also.

But here is my observation from Two Towers, native 6.1, horses riding from center to right:

No DSP on:
Channel 5 (which is to be channel 7 when mixed to 7.1): Very low ambient sound only, some times not visible on mixer VU meter.
Channel 6 (which is to be channel 8 when mixed to 7.1): Horses hoofs and ambient sound.
Channel 7 (which is to be channel 5&6 when mixed to 7.1): Very low ambient sound, diffuse.

Switching on JRSS upmixing to 7.1:
Expected horses to come from Ch. 8, but it actually sounds from channel 7.
It sounds like Ch 5 & 6 has switched places.
Because the rear center (original Ch. 7) is so diffuse, it is difficult to tell if the new Ch 5&6 is a variant of it

Another observation from Two Towers disc 2 1:41:42, native 6.1:
The original center back (Ch.7) sound like ambient sound and distant screams. In the upmixed Ch. 5&6 (rears), it does not sound anything like that, as the dominant sound is music score from the fronts.
Again, it sounds like the new Ch. 7 (SL) picks up a lot from one front, and gives a totally different image than Ch 8 (SR). Ch.8 on the other hand sound very low and much like the original rear center.

Conclusions:
For me, it sound like 5.1, 5.1 upmixed to 7.1, sounds ok, and channels are correct.
Also, 6.1 upmixed to 7.1 is totally screwed up (no offense!!!)

[mojave]

In the LAV Audio Decoder Properties there is the option to expand 6.1 to 7.1. If you change the DirectShow selection method to "Advanced" and use a manual installation of LAV Filters, you can access this option. I wonder if it sounds better than JRSS. I have LOTR EE Blu-ray and a 7.1 system. I might compare if I have time.

[Trumpetguy]

That did the trick! All channels seems to be in place.

But it would still be good if MC JRSS could handle 6.1...