ogg 5:1 -> SPDIF

[jernst]

Hello,

I'm thinking to start using ogg 5:1 sound streams instead of mp3 stereo sound in my movies but wondered if:

1)This feature was well supported by ogg already
2)The resulting file will be much bigger than my stereo mp3 file
3)(the most important thing) I have spdif out on my sound card and wondered how I can make my home dolby digital decoder to distribute the 6 channels to my speakers (I don't have the decoder nor the speaker, so, if someone knows about a special hardware ogg decoder I would be happy too). As far as I can understand this won't work if my hardware decoder doesn't support ogg (and I don't think I will find one), so what about a way to "connect" the ogg decoder with ac3 encoder (by software I mean) then to give the resulting stream to soundcard ?

thanks !

John

[MaTTeR]

Ogg is a container file like AVI, Vorbis is the audio codec.

1. Vorbis to SPDIF out works fine but of course your amp will only detect it as PCM 2 channel

2. A Vorbis 5.1 will most certainly be larger than your stereo MP3, do a short clip to see how much.

3. AFAIK an Ogg Vorbis hardware decoder in amps doesn't exist. For multi-channel playback your stuck with analog outs if your sound card supports such a thing. Awhile back a few people on here were looking at writing an on-the-fly AC3 encoder as you mention but I'm not sure how far it progressed. A quick search should turn up the thread.

[ChristianHJW]

There is another chance also :

AFAIK the SPDIF interface norm would support 6 ch PCM also, unfortunately only a very small number of surround receivers seem to support this at all ( anybody has a link to a list ? ) ...

In principal it should be possible to find a combination of soundcard/reciever allowing to

- export uncompressed 6 ch PCM audio via SPDIF, using soundcard driver

- playback the 6 ch PCM in a surround receiver supoorting this input format

Probably the better way to do it, at least from a technical point of view. Although its quite frustrating to know that this solution could never become a generally usable way to listen to 5.1 Vorbis through external receiver ... :( ..