[vorbis] Vorbis on Legacy hardware

[Segher Boessenkool]

"Kenneth C. Arnold" wrote:

> For Vorbis with channel coupling, decoding to mono is nearly as much
> effort as decoding to stereo.  Perhaps some savings could be gained by
> just dropping off the second iMDCT for a stereo stream and treating the
> result as mono, though it would probably sound better to try to extract
> a "middle channel" earlier, in the decoupling code.

...and that is exactly the reason why channel coupling _helps_ for
doing a faster mono decode of stereo material: change the codebooks
(in the decoder, when reading the headers) to provide already-downmixed
mono output.  Note the same trick can be done to change the codebooks
to already-coupled values for normal stereo decoding :)

<p>Segher

<p>--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.