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View Full Version : Vorbis 5.1 & AC3 5.1 ?


ookzDVD
5th November 2002, 06:51
@Forum,

Sorry for posting this,
but I really want to confirm about the channel mapping for the
Vorbis 5.1, is that different with the AC3 5.1 ?

I have playback problem with the Vorbis 5.1.

Thank you.

JohnMK
5th November 2002, 06:54
What's the combined bitrate of a 5.1 ogg vorbis file at whatever q you're using?

ookzDVD
5th November 2002, 07:09
@JohnMK,

I'm using -q 0.250 which will produce ~320 total bitrate.

JohnMK
5th November 2002, 07:12
Doesn't seem to be worth it in that case. Why not keep the original AC3 track @ 384 or 448kbit/s?

ookzDVD
5th November 2002, 07:14
@JohnMK,

Sure, I just want to test it ;)

DSPguru
5th November 2002, 18:26
front left, front center, front right, rear left, rear right, LFE :).

ookzDVD
6th November 2002, 03:16
@DSPGuru,

thank you for the info,
btw, so I should hear the correct sound at the correct channel then,
why the Peter's in_vorbis should hack with "remap" for the playback ?

Thank you.

tiki4
6th November 2002, 13:07
Hi all,

I was wondering about that, too. For example, I can play AC3 in Windows Media Player with iviaudio.ax 4.0 without any problems. When I try to play 5.1 Vorbis I get no sound at all, choosing wavOut instead of DirectSound I can hear something but it's garbled.

In Winamp (2.81) I have to choose 'remap 6 channels' to hear the channels in the right speakers (in_vorbis 1.2.9). I never got 5.1 AAC working in whatever player I tried (Quicktime 6, mpegable player, Winamp (AAC and MP4), Envivio plugin for WMP).

Yesterday I installed the release candidates of Windows Media Player 9 and Windows Media Encoder 9 and tried WMA9 Professional for one song of one of my concert DVDs and it worked like charm (?).

I really like to know what's going on here. Is it just the crappy Audigy (that otherwise produces nice sound IMHO) or is it something not very well defined in the DirectShow components of Windows?

Regards,

tiki4

ookzDVD
7th November 2002, 11:02
@tiki4,

I think the "remap channel" in_vorbis 1.29 still produce the
wrong channel mapping, the center sound is heard in the Front Right. :(

The multi channel playback still mystery in the M$ world :(

tiki4
7th November 2002, 12:03
@ookzDVD:

You maybe right about the channel remapping. I didn't test that extensively as I only have little use for playing 6 channel files in Winamp. Still, why the hell does AC3 and WM9 work while Vorbis and AAC/MP4 doesn't? By the way do you know about any MP4 player that can play 5.1 AAC in MP4 container? It's just for testing, but I think that any ISO MPEG4 compatible player should play such content. Not any did for me (Envivio TV, Quicktime, mpegable DS, mpegable player) though I didn't try RealONE yet.

Regards,

tiki4

ookzDVD
7th November 2002, 12:36
@tiki4,

Sorry, I don't know about the player, since I never "touch" the MP4 container ;)

Btw, about WM9 5.1, is that easy to encode the AC3 -> WM9 5.1 ?
I really want to try, what tools should I have to do that ?

Thank you.

tiki4
7th November 2002, 14:14
Oh,

you just need the Windows Media Encoder 9 Release Candidate (and maybe WMP 9 RC for playback). 5.1 WM9 will only work in Windows XP though, all other OS's will downmix to stereo.

For encoding I just took a song from the U2 Elevation CD, made a DVD2AVI project file, converted to AVI with VFAPIReader. The AC3 was demuxed then to 6 mono waves (with BeSweet) which you can select as audio device in WME9. Better would be to do resizing in Avisynth, but WME doesn't accept that (you'd need Link2 from Edwin, but it costs money!).

Nic has an alternative WMEncoder on his site but this one cannot creative 5.1 WMA9.

Quality is quite O.K., but speed is terrible.

Regards,

tiki4

tiki4
12th November 2002, 09:29
Woh, I'm surprised, so here's a little update:

I didn't know that, but WME9RC actually 'eats' Avisynth script files. You still need six mono waves as input for 5.1 WMA Pro. On the other hand this seems to work pretty good. I encoded a short bit at 384 kBit and it sound really nice. I tried to play the video and audio in Winamp and this actually worked in Winamp 3 though it just sees a mono audio track instead of 5.1. I didn't test that in my XP yet as I use Winamp 2.81 there at the moment for my MPC files.

Just give it a try: Video source: AVS, audio source: 6 mono waves created with BeSweet. It seems that the first time M$ aims directly at the DVD backup community.

But of course: XviD + AC3 in OGM is much better!

tiki4

ookzDVD
12th November 2002, 09:47
@tiki4,

Thank you for your update,
I will play around with M$ WM stuffs this week end ;)