Well, went through reading a lot of pages on the subject since my first post... and I think it could be useful to post some of my discoveries... and also hope one of the MJ's gurus might come cross this one and share his feelings about the subject. So here it is:
Playing 5.1 sound of course requires a multi-channel capable sound card:
1. either through
discrete speakers output (one per channel) - solution that requires the decoding of the sound stream
2. or
through SPDIF to an external decoder - solution which requires a AC3- or DTS-compliant sound stream (unless you have some very fancy decoder, with very fancy sound format support).
Now, if you have a
solution 1. compliant sound card, any multi-channel format (OGG, AC3, DTS (native or WAV encoded), etc...) would be fine...
provided you have the appropriate decoder software (plug-in). MJ currently lacks those...
If you have a
solution 2. compliant sound card, then you need to save your music in AC3 or DTS (native or WAV encoded) and
have the appropriate software (plug-in) to play the sound stream directly to the SPDIF connector (passthru mode, somehow). MJ currently lacks this too, except for WAV encoded files...
Now comes the question of
storage place: OGG (multi-channel), AC3 and DTS sound streams share the advantage of being highly compressed compared to AC3/DTS WAV encoded streams (by a ratio commonly close to 1 <-> 5). When speaking of about 10-15 MB per minute (600-900MB per hour), one may easily understand that
WAV-encoded sound streams are not the best options... though they are what you find the most commonly on the internet for now and are
the only solution available so far on MJ to obtain 5.1 sound through SPDIF and an external decoder.
Now, when speaking of native AC3 or DTS sound streams comes the question of
legal rights and how to obtain such encoded streams: AC3 is a proprietary format owned by Dolby Labs, who - it seems - requires a "licensing" fee for any application/software plug-in able to encode/decode AC3 sound stream. I'm not sure about DTS, but I think the problem is the same.
Plainly speaking, it means
one has to PAY to be able to decode/encode AC3 or DTS... unless you use Linux (cf. liba52, still freely distributed though not very legal) or some pirate software.
The discussion comes pretty close to the DVD ripping/burning subject, on which two excellent sources exist:
http://www.digital-digest.com and
http://www.doom9.orgCould MJ provide a AC3/DTS decoding plug-in in the frame of the "MJ Plus" licensing fee (would that cover Dolby Labs fees) ?
If not, it means we would have to pay to obtain a decoding plug-in, and then, how much ?... provided of course MJ (or any other third party developping plug-ins) is willing to go through the harness of contracting with Dolby Labs.
Now,
provided you have an encoded AC3/DTS sound stream (as a separate file, on a DVD or encapsulated in a VOB file... no matter how you obtained it) and
you just want to pass this stream through to the SPDIF connector,
NO encoding/decoding would take place.
Wouldn't this free any "passthru" plug-ins from the Dolby Labs licensing fees ? (I read something like this on the Internet, but it didn't look very official)
If yes, couldn't MJ easily (contractually speaking) provide a AC3/DTS playback plug-in ?OK. Why go through all this ? Well, the answer is quite simple: have your eve listened to a properly mixed 5.1 sound stream ? IT'S TERRIFIC! It would be great to have other-than-WAV-encoded solutions to build a 5.1 music library.
Wow... that was a long draw! I apologize for the length of this message. I hope I also understood right what I read through various web pages and didn't make a fool of myself (if so, please DO correct me)!
Hope we're heading towards 5.1
Author
Topic: AC-3 Dolby/DTS 5.1 support ? (Read 3971 times)