Convert avi back to mpeg2 - ac-3/6

[eric67]

Hello. I've got a DVD that I ripped down to an AVI, then back to mpeg2 but I haven't been able to get 5.1 dolby digital (ac-3/6) back, I end up with ac-3/2 only. Is this because of the way I ripped it down to begin with and the audio can't be converted back ?

Thanks for the help.

[manono]

Hi and welcome to the forum-

Open the .avi in GSpot (http://www.doom9.org/Soft21/Editing/gspot221.exe) and see what it says. I'm pretty sure you still have the 6 channel AC3.

[jggimi]

"3/2" = 5.1ch

3 forward speakers, 2 rear speakers, LFE channel assumed.

[KpeX]

Just to add some more clarification (hopefully not confusion):

AC3 is the name of the format. AC3 is the same as A-52 is the same as Dolby Digital. See the link in my sig for an AC3 FAQ.

Therefore AC3 3/2 = AC3 6 = AC3 5.1.

[eric67]

Thanks for the welcome .......

manono - GSpot shows "MPEG-1 Layer 3" for the 3/2 movie. I have another AVI attempt that shows "ac3 (0x2000) Dolby Laboratories, Inc" but I haven't tried to convert back yet.

jggimi - My receiver shows only the 2 forward speakers (L & R), no LFE channel. I thought 3/2 was just the 2 channels ?

KpeX - Great FAQ link. I think that's the one I was looking through the other day and found it very informative but a little too much for this newbie. It'll take more practice I guess.

Thank you all for the help.

[manono]

Hi-

GSpot shows "MPEG-1 Layer 3" for the 3/2 movie.

You didn't say that you had converted the audio to MP3. I assumed you had the DD 5.1 in the .avi. Silly me.

I have another AVI attempt that shows "ac3 (0x2000) Dolby Laboratories, Inc

Read down a bit, under Bitrate, and it tells you the bitrate, and how many channels there are. Nothing to convert, if AC3 is what you want.

My receiver shows only the 2 forward speakers (L & R), no LFE channel. I thought 3/2 was just the 2 channels ?

You thought wrong. Maybe it's just that the Surrounds or the LFE aren't active in the places you looked. Or maybe somethings going wrong with the audio transmission from your computer sound card to your receiver, if that's what you're doing. For example, my computer has only 2 speakers, and the sound card is set up to output for 2 speakers. But when I send a movie to the TV set (and the audio to my receiver), I have to turn on the S/PDIF Out in both the soundcard and the AC3 Filter, or else I'll get the same stereo output.

[eric67]

So I see I goofed on the initial rip to avi but not the 2nd attempt that shows Dolby in GSpot.

I was using my dvd player hooked up to my TV receiver, not from a pc. So is that scenario truly only 2 channels when playing the avi (with MP3) that was converted back to dvd ?

thanks again

[jggimi]

MP3 is either mono or stereo, and since the source was originally AC3, I'm betting on stereo. That's two tracks. It will likely have Dolby Surround (tm) included in the stereo downmix. However, you will have lost the separation of the individual rear and center tracks.

[eric67]

Thanks jggimi, that makes sense. Thanks all for the help.