Number of channels? Is AAC always 2 or 6 channels?

VideoBeginner · 15th June 2016, 20:01

I have a collection of files that I want to know the number of channels that each uses. The only method I know of for finding this out is to open the files into MediaInfo.

It shows that every file (with the exception of one) out of several hundred as AAC or AC-3 use either 2 channels or 6 channels. I find it difficult to believe that there are no 5-channel encodings, for instance.

Am I reading this wrong, does MediaInfo give false information, or does AAC real only use these two sets?

LoRd_MuldeR · 15th June 2016, 20:31

6 channels (aka "5.1") is the most common speaker configuration, by far, used with AC-3 audio.

As MediaInfo indicates, this contains 3 "front" channels (left, center, right) plus 2 "surround" channels (left, right) plus 1 "LFE" channel (subwoofer).

See also:
https://en.wikipedia.org/wiki/5.1_surround_sound

filler56789 · 15th June 2016, 21:29

Quote:

Originally Posted by VideoBeginner

.......
or does AAC real only use these two sets?

https://github.com/nu774/qaac/wiki/M...nnel--handling

VideoBeginner · 16th June 2016, 04:17

Quote:

Originally Posted by LoRd_MuldeR

6 channels (aka "5.1") is the most common speaker configuration, by far, used with AC-3 audio.

Oh... 6 channels is the same as 5.1 surround? I never knew/realized that.

That explains a lot and actually solves the core cataloging issue for which I wanted to know this info in the first place.

Thank you very much.

Quote:

Originally Posted by filler56789

https://github.com/nu774/qaac/wiki/M...nnel--handling

Thank you for the link. I will take a look.

LoRd_MuldeR · 16th June 2016, 18:13

Quote:

Originally Posted by VideoBeginner

Oh... 6 channels is the same as 5.1 surround? I never knew/realized that.

"6 channels" just means that there are 6 distinct channels. The number of channels alone doesn't say anything about the speaker configuration.

However, the most common use of 6 channels (by far), especially when it comes to AC-3, is the standard "5.1" setup (3 front speaker, 2 surround speakers plus a sub-woofer). That's what is used on pretty much all Video-DVD's.

Side note: For compressed audio, such as AAC, the channel layout (not just the sheer number of channels) does matter, because "joint coding" works best between related channels...

15th June 2016, 20:01	#1 \| Link
VideoBeginner Me Join Date: Aug 2007 Location: United States Posts: 39	Number of channels? Is AAC always 2 or 6 channels? I have a collection of files that I want to know the number of channels that each uses. The only method I know of for finding this out is to open the files into MediaInfo. It shows that every file (with the exception of one) out of several hundred as AAC or AC-3 use either 2 channels or 6 channels. I find it difficult to believe that there are no 5-channel encodings, for instance. Am I reading this wrong, does MediaInfo give false information, or does AAC real only use these two sets? Attached Images

15th June 2016, 20:31	#2 \| Link
LoRd_MuldeR Software Developer Join Date: Jun 2005 Location: Last House on Slunk Street Posts: 13,248	6 channels (aka "5.1") is the most common speaker configuration, by far, used with AC-3 audio. As MediaInfo indicates, this contains 3 "front" channels (left, center, right) plus 2 "surround" channels (left, right) plus 1 "LFE" channel (subwoofer). See also: https://en.wikipedia.org/wiki/5.1_surround_sound __________________ Go to https://standforukraine.com/ to find legitimate Ukrainian Charities 🇺🇦✊ Last edited by LoRd_MuldeR; 15th June 2016 at 20:33.