How long till we get 5.1 vorbis with channel coupling?

[The Belgain]

I know I'm not the only one being impatient about this, and also that sofware is ready when it is ready and all that, but I really can't wait till I can start having 5.1 sound at the kind of size that would make it feasible to put on a 1 CD rip.

Is there any way at the moment to get 5.1 sound from AC3 sizes down to under 192 kbit say? Will vorbis be able to do this with channel coupling?

Also when will there be a downmixer for 6 channel vorbis?

Sorry if I'm sounding a little impatient.

Anyone know when RC4 is coming out?

[MaTTeR]

http://www.doom9.org/transcode_ac3.htm

For 1CD rips I just transcode the 5.1 AC3 files down to 256kbps.

At the moment Xiph is very busy trying to get Vorbis 1.0 released and out the door. Emmett told me a few weeks ago that as soon as 1.0 is released then the 5.1 Vorbis work should be pretty heavy.

[DSPguru]

Originally posted by The Belgain
IIs there any way at the moment to get 5.1 sound from AC3 sizes down to under 192 kbit say? Will vorbis be able to do this with channel coupling?why not using AC3Machine to reencode your original AC3 to a lower bitrate AC3?
the biggest advantage of this method is that you preserve the option to playback your stream thru spdif ;).

[hippoth]

thats right what dg says...ogg machine is a powerfull tool...i like it very much :D
I say thank you to dg for his great work!! ;)

[The Belgain]

I've tried to use AC3 Machine, but it won't let me open the ac3 file outputed by DVD2AVI (when I select open ac3 file, the file just isn't there). Will the sound still be decent quality at 256 in 5.1 using ac3?

I suppose that it's not really possible to go any lower than that using ac3 without degrading the sound quality too much?

By the way I am using the latest versions of both AC3 Machine (0.3 09.06.02) and BeSweet (1.4b3).

[MaTTeR]

I have the same problem, it doesnt even see any of the AC3 files. So after beating my head against the wall for 30mins I gave up and blamed my laptop:D

Yes, 256kbps will give very nice 5.1 quality. In fact, you will most likely not hear any artifacts. Personally, I haven't tested anything lower than 256kbps and would be reluctant to go lower.

[The Belgain]

Ok, so that problem does seem to be a bug.

It still accepts the ac3 file if you just copy and paste the filename manually. What downmix options should I use to keep exactly the same channel mapping as the original ac3? I can't test this since I currently only have a 2 channnel setup :(

I guess I'll stick with 256 then even though that's a little large for most 1 CD rips.

[MaTTeR]

I'm using 256kbps with 1CD rips easily but I'm also using Mode2CDMaker(aka. XCD) to burn 805MB instead of 705MB to an 80min CD.

Can't really comment on the quality of this tool at lower bitrates because I have no access to my 5.1 system for another 6 weeks or so(stuck in a hotel on business). It appears DSPguru has the default bitrate at 224kbps so I guess he feels comfortable going this low.

In regards to the channel mapping, selecting 5.1 should be fine for channel mappings. Not sure why the DRC is disabled by default though. Maybe Dg could provide a little more information on the options.

[The Belgain]

Do u mux ac3 into an avi?

If so how risky is it burning it without error protection?

[MaTTeR]

I'm muxing the AC3 into the AVI using NanDub of course. After doing that I manually use GraphEdit to convert this into an Ogg(OGM) container. So far the error protection hasnt been an issue at all. I did some testing on light scuffs and scratches and the disc still plays flawlessly.

I have to advise against this since the readme file says so though;)

[The Belgain]

Is there an issue with bad frames using DivX 5.02 and ac3 in ogm container, or what that just an issue with Vorbis?

Or do you use XviD?

[MaTTeR]

I don't use Divx 5.x but yes apparently people using it are having to revert back to AVI and MP3 audio as it seems jerky playback is happening. These issues aren't seen with Xvid which is what I prefer to use.

[DSPguru]

Originally posted by The Belgain
Ok, so that problem does seem to be a bug.

It still accepts the ac3 file if you just copy and paste the filename manually. writing "*.ac3" in the filename textbox + clicking on 'enter' will do the trick.
i'll ask DD to help me excluding this stupid bug.
What downmix options should I use to keep exactly the same channel mapping as the original ac3?5.1 .

@hippoth
10q :).