Remapping channels...Can not find the option

jmc

Well-known member
Found "Audio Meters" (they only mute channels temporarily)
but can not seem to find where to edit the Audio Channels (Not streams) as in delete, merge etc.

Thought I found it before but been over everything twice and I'm missing it somehow.

Thanks,
jmc
 

Dan203

Ex-Senior Developer
You have to use the grid profile editor. In that editor make sure the mode is set to advanced. On the audio tab change the audio mode to advanced. That will open a secondary dialog. In that dialog there are two lists. The "process" list is how you want the channels mapped for processing, like normalization, the "output" list if how you want the channels mapped for output. It's a bit complex but in yhe broadcasting industry they typically have 5.1 audio separated into three 2ch streams. They need to be able to combine those streames into 5.1 for LKFS normalization, but then separate them back out to three separate streams for output. For your use you'd just ignore the process list and do the mixing in the output list.
 

jmc

Well-known member
You have to use the grid profile editor. In that editor make sure the mode is set to advanced. On the audio tab change the audio mode to advanced. That will open a secondary dialog. In that dialog there are two lists. The "process" list is how you want the channels mapped for processing, like normalization, the "output" list if how you want the channels mapped for output. It's a bit complex but in yhe broadcasting industry they typically have 5.1 audio separated into three 2ch streams. They need to be able to combine those streames into 5.1 for LKFS normalization, but then separate them back out to three separate streams for output. For your use you'd just ignore the process list and do the mixing in the output list.
Think I found the options.

I loaded a MPG with 5.1 AC3 audio. The top "process" area is blank.

The "output" (streams) list does show 5.1 audio.
"Edit" gives "Audio Stream Properties" - "Source Stream" - "Source Sream 1"(if I change this to "Mix")...

I get Channel options that are not all grayed out.

"Mix stream"-Number of channels 2
--"Left"-Number of mix channels 1
--"Right"-Number of mix channels 1


Heh, you did say "a bit complex", I'm still looking for 6 channels.

------------------
EDIT... A 2 channel audio stream gives the SAME "Mix stream" data as
the 6 channel audio stream above.
-----------------

Looks like I found two channels so far. The other 4 channels are where?
This is the only window that will let me alter the channels.

I'm guessing that if I set a "mix channel" to 0 then it will be deleted?

Lots of "trial and error" ahead.

thanks,
jmc
 
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Dan203

Ex-Senior Developer
So for output each channel can be a mix of up to 8 input channels, so that's why it's so complex.

What's your purpose here? You trying to mute a channel? If so you can set the factor to 0.0 and it will mute that channel.

Keep in mind though that we do not support AC3 output, so you can only output 5.1 to AAC or PCM.
 

jmc

Well-known member
So for output each channel can be a mix of up to 8 input channels, so that's why it's so complex.

What's your purpose here? You trying to mute a channel? If so you can set the factor to 0.0 and it will mute that channel.

Keep in mind though that we do not support AC3 output, so you can only output 5.1 to AAC or PCM.
What I do is if all the music is on one or two channels then I delete them and keep the voice channels.
Sadly not common but wonderful when they seperate it like that.

1."So for output each channel can be a mix of up to 8 input channels"
Sounds like my 5.1 channels could ALL be in ONE channel in "Output". ?
I can't be interpreting this correctly as this would defeat the whole purpose of channel editing.

I have to be able to find each of the one or two "music channels" and mute/delete them.

2.I can get 2 channels to display when I select "mix" and can alter the channel settings.
But how to get the other 4 channels (of 5.1) to be displayed so I can change them?

3.Unless I'm missing something, I see no way to tell what is on the channels that I am able to change. (2 of the 6)
Is it LFE that I want to keep or the music that I want to delete?

Is trial and error the only way to edit the channels, delete one and then listen to it to find out what I took out?

Hmm, you said 0.0 Mutes.
I was hoping it would delete. Then I could reload and have 2 new different channels displayed since the first two would be gone.

Hope I can get the hang of this. Would save a lot of steps with "Audacity".

Thanks,
jmc
 
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Dan203

Ex-Senior Developer
In the output a single channel can be a mix of up to 8 channels. This was added so that you could do things like convert 5.1 to 2ch with Pro Logic. It has no bearing on what you're attempting to do unless you want the output to be 2ch instead of 5.1.

After you change the source stream to "mix" there is a line called "Number of channels", change that to 6. For each channel leave the "Number of mix channels" at 1. Set the source stream to the source stream with the 5.1 audio. Then set each channel index to an increasing value 0-5. From there you need to figure out which channel you want to mute and set it's factor to 0.0. You could just skip a channel but then the output would only be 5 channels (or 4 or 3). If you want the output to be 5.1 you have to have 6 channels and just silence the ones you don't want.

As for how to figure out which channels are which.... The default layout for 5.1 is Left(0)/Right(1)/Center(2)/LFE(3)/SL(4)/SR(5) and unless you have a special file with an alternate layout indicated in the file that will always be the order. The easiest way to figure out which channel has which audio is to use the meters. Launch the meter for your audio stream in the UI and you can use that to mute individual channels and figure out which ones you don't want.
 

jmc

Well-known member
Thanks so much!
I would have never sorted that out just poking around with it.

There is hope I'll be able to wrap my head around it with practice!


jmc
 
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Dan203

Ex-Senior Developer
Yeah we went a little overboard with the individual channel mixing, but it was needed to support special down mixing like Pro Logic. But if you notice we don't support individual channel mixing in the UI audio profiles. That seemed like overkill there since internally we automatically downmix all audio to Stereo for playback anyway.

What's worse.... we're getting requests from multiple customers to support more audio streams. (up to 32) So this could end up getting even more complicated. :eek:
 
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