5.1 MP3 Encoding

[FreQi]

I'm probably jumping the gun here, but I just read the news article (http://www.mi2n.com/press.php3?press_nb=63979) linked from the front page here at doom9, and I'm pretty excited about the idea of a completly backwards compatable 5.1 MP3. Is there anything known about this new development yet? I am particularly interested in the bitrate requirements. Can we expect the same quality and size from --r3mix or --abr 160 encodes, or will the additional 4 channels greatly impact file size?

I haven't found anything else about it on Fraunhofer IIS (http://www.iis.fraunhofer.de/index.html)'s, LAME (http://lame.sourceforge.net/)'s nor DSPGuru (http://dspguru.doom9.org)'s site.

I'm just anxious to try out some 5.1 MP3 XviD's ...

[bond]

i doubt that mp3 will be able to bring good quality at 160kbps, many people even say that it doesnt bring great quality for stereo at that bitrate (heavily depends on the encoder used)

edit: reading it again it doesnt seem to be "real multichannel" as we know it but simply a stereo file with some extra info which upmixes to multichannel with decoders which handle it

anyways this idea is defintitely coming years too late :(
seems like they want to cash in once more before the (far) better formats succeed totally

[SeeMoreDigital]

I wonder if it will use some form of SBR technology for the surround sound channels!

Cheers

[P0l1m0rph1c]

Anyway, you have Gabriel (LAME developer) talking about source availability for such kind of encodes.here (http://www.hydrogenaudio.org/index.php?showtopic=11765&view=findpost&p=120060)

So, you souldn't expect any free encoder for this very soon...

[SeeMoreDigital]

I remember Doom9 telling me that 6Ch (or most probably 5Ch) Mp3 was a standard developement feature for Mp3 when it was originally conceived. However, it was never developed.

If anybody can provide such a file, I would love to add it to my collection.

Cheers

[planet1]

@FreQi

since we have to wait - for the first 5.1 (i hope up to 7.1) MP3 encoders, why dont you try 5.1 MP2 (Mpeg 2 Multichannel Audio - Backward Compatible) in the mean time.

http://hypercube.is.dreaming.org/

(the only free and "working" multichannel audio encoder for DVD)

i know its a near dead format, but still its an official format for DVD and SVCD - and its compatible with any ordinary mpeg 1 layer 2 audio decoder ;).

[KpeX]

At one point I believe I had heard that Lame 4.0 would include true multichannel encoding. And it is correct that true multichannel encoding is part of the MP3 spec.....as mentioned in the MP3 FAQ ;)

[FreQi]

@planet1

I do a lot of encodes from HDTV sources, and I primarily do ~1000kbit XviD's at 624x352 with 2ch MP3 using LAME and --r3mix (it's an old habbit, and I am quite content with the quality). However, I bought a DVD burner a couple months ago, so I have been gradually switching to doing my encodes with CCE and making DVD compliant MPEG's. Since my sources are OTA HDTV, my source audio (at least for ABC) is 5.1 AC3 at 384k. So I no longer process the audio, aside from cutting the commercials out of the TV shows and running the .ac3 through ac3fix and/or besplit.

Being able to do my XviD's with 5.1 MP3, but having it behave the same as all my previous encodes is very appealing. I do not like to switch my encode formats in mid season of a series, so having the first half of a season in XviD with stereo MP3, then the second half in MP2 is just not something I would do :/ But the idea of a 5.1 MP3 that behaves exactly like a 2ch MP3 on legacy decoders would be something I'd be willing to at least entertain.

[21_already]

As far as i can tell it doesn't use SBR (that's pretty much what MP3 pro is), it's something new and from what i heard on HA, this new development is propriatry and does not conform to any MPEG standards. That having been said, maybe it would get adopted in the future, i guess not for mp3 but for AAC which really does bring better quality at 160kbps and would probably ensure backward compatibility with existing decoders ... oh yeah, there are none :p

Look into my crystal ball:
I see 5.1 56kbps HE-AAC+PS+SI (Surround Information:p -i made it up)

PS, I reckon it won't increse bitrate much at all, just look at what DPLII can do with zero extra bits