[vorbis-dev] Re: Re: How is 6 channels coupling made?

ChristianHJW christianhjw at users.sourceforge.net
Mon Sep 9 23:16:58 PDT 2002

"MiwongShaib" <miwongshaib at hotmail.com> schrieb im Newsbeitrag
news:OE32tUHzXrJGpkeH9ur00002c6d at hotmail.com...
> > unfortunately there is no channel coupling used at all when doing 6 ch
> > Vorbis encodings, thats why files are currently bigger than they should
> Thanks for telling.
> This makes things easier for me: it's safer to patch the bug like this
> Just curious: is there any channel coupling when encoding 2ch (stereo) ?

Of course there is, depending on q level. For q > 5 lossy mode is disabled,
thats why from 4.99 to 5.0 there is a rather huge jump in bitrate. There are
vorbis encoder exe's around with experimental disabled ( non-lossy ) or
fully enabled ( lossy ) channel coupling, irrespective of q level, but i
guess those were RC 3, not 1.0.

However, based on those DarkAvenger had implemented selectable channel
coupling in HeadAC3he independant from q level, very helpful if a Dolby
ProLogic surround Stereo was to be encoded ( channel coupling disabled,
bitrates about 100 - 120 kbp/s at q = 2 - 3, sounds nice )

> <Offtopic>
> Also I spot a link in which you were talking about how to couple
> tracks:
> rt=0
> I understand nothing about coupling but... it seemed like you had skipped
> most obvious coupling:
> FL of one language coupled with FL of the other language,
> FR of one language coupled with FR of the other language,
> FC...

Uhh ! That old idea of mine .... storing more than one language in one big
multi channel track instaed of having several Stereo tracks. The idea was
abandoned, although i had proven here (
test ) that there is some saving to be expected.

<p>> > BTW : did you test HeadAC3he and BeSweet also for 5.1 Vorbis encodings
> > AC3 sources ?
> Yes, HeadAC3he, and the channels are not swapped.
> > Are they swobbing channel oder as well ?
> no

Thats what i thought. But its not the recommended way to use Tobias's
filters for encoding in any case, bith DSPguru and DarkAvenger update their
tolls much more frequently.

<p>> I'm not sure if I should release such a patching-filter to the public. I
> Tobias to fix that!

Agree here

<p><p><p>--- >8 ----
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