[Vorbis] Does Ogg Vorbis support 5.1 surround?

Paul Ellis paul
Thu Aug 5 20:39:18 PDT 2004


<20040805160610.GA25377 at ghostscript.com>
Message-ID: <4066.144.37.177.95.1091763558.squirrel at www.ellisfoundation.com>

> On Thu, Aug 05, 2004 at 09:21:22AM -0400, Cory wrote:
>
>> As most of you all know, DVD's have 5.1 audio, and I want to preserve
>> that in my voribs files.  So, to ask the question : Does it support
>> Surround sound?
>
> Yes and no. There are two issues here. Vorbis does support 6 channel (or
> any other number of channels) just fine. So in that sense it works.
> However, there are currently no tuned modes for 5.1 surround. This means
> the compression will be less effecient than it could be until someone
> publishes such modes.
>
> The other is that the surround audio on DVD is already compressed with a
> lossy perceptual codec, so re-encoding that as vorbis will always be
> lower quality than if you had access to the uncompressed soundtrack,
> like what music cds give you.
>
> Hope that helps,

While this is true, I have found the quality to be quite good.  Of course
it won't be as good as from source files, but transcoding from MPEG-2 to
MPEG-4/Divx/Xvid is also lossy, this is all far from best case scenario.
I would say that when I have encoded material at Q0 (remember this is
simple speech most of the time) I can't really notice the difference.
It's not music, so the artifacts seem less audible or perceivable.  Well
that's my 2 cents.

Paul


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