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

[VideoBeginner]

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]

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]

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

https://github.com/nu774/qaac/wiki/Multichannel--handling

[VideoBeginner]

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.


https://github.com/nu774/qaac/wiki/Multichannel--handlingThank you for the link. I will take a look.

[LoRd_MuldeR]

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...