GKnot and AC3...newbie questions...

[angelleye]

When using GKnot to do DVD -> Divx and trying to get the AC3 Surround sound in the finished product...I have a couple of questions:

1) Do I simply have to select the AC3 file under Audio A in the Bitrate tab? And then select Just Mux at the end...is that it? Will that take care of everything for me? Dolby Pro Logic surround would be inserted???

2) When I do a DVD rip sometimes they have 2 or 3 AC3 files on there. Anytime I've done movies (in the past I always did mp3 sound and finally mux) I always just picked the first AC3 file and it worked out fine. What are the others though? And do I need them when I'm trying to do the AC3 sound in my finished Divx movie? I see there's the Audio B section.

I've just been confused...is that another language or is that part of the 5.1 surriound that it would need. And if so...what happens when there are 3...I only have audio A and audio B in GKnot to work with.

Any information on these questions would be greatly apprecaited.

Thanks!

Drew

[angelleye]

on the same note...when encoding the movies with the AC3 do I HAVE to have a sound card that supports 5.1 surround like on the expensive audigy cards?

Right now all I have is a SoundBlaster Live card. If I do my encodings and then play my divx movies on a computer that supports the Dolby surround will everything be ok?

[angelleye]

well, i did some browsing around in my control panel and realized that the SB Live does support 5.1 surround. So I think I'm good to go...

Any info on my original questions would be great....thanks!

[angelleye]

i've been playing with a small VOB from the set. each time I use the AC3 sound and I select Just Mux I end up with a file that will not open in windows media player. no errors..it just closes itself.

the avi will play in both the ATI player I have and Divx Player.

Checking it out with AVIcodec it's showing:

Video : 48 MB, 1487 Kbps, 29.970 fps, res. 352*256 (4:3), DX50 = DivXNetworks Divx v5, Unsupported


Why would it be coming up unsupported? The audio shows up AC3 and shows supported (i've got ac3 filter installed) why woul using AC3 effect my video support? Anytime I encode movies and choose to Finally Mux with MP3 I get supported everything and it plays fine in any player.

Any info is great as always...sorry all the replies to my own post...

[killingspree]

hi,
well it seems that reading through the forum would have gotten you most answers, but here's some points anyway:

Yes, just mux is all you have to choose. you'll end up with identical sound as your DVD has.
to be able to play avi files that contain ac3 audio you have to install a special filter. i would recommend ac3filter which you can find in the doom9 dl section.
you can play ac3 with (almost) every soundcard. if you just have a stereo card you'll just have 2 channels and can't make full use of the information contained in the ac3 file...
most of the time a DVD contains more than one language. for each language you get a seperate ac3 file. in addition the directors commentary (or alike) are also kept in an extra ac3. you can use ifoedit for example to find out what ac3 file contains the english audio stream (or whatever you want)


hope this helps
steVe

edit: instead of writing a new post every time, you can just edit your existing post!

[angelleye]

thanks for your reply...I had ready through the forums and many guides...but hadn't really seen exactly what what I was asking.

Anyway, I've figured out that my problem opening in media player isn't the AC3...it's that I used 2 audio streams.

I was looking at the Stream Information that DVD Decrypter gives me and it shows one is a 2 channel audio and the other is a 6 channel. So I used the 6 and tried again and it works out ok.

When, though, would I want to use 2 audio channels?

[killingspree]

i'd suggest you download and install the audio filter package then. it will allow you to play avi files with two audiostreams.

anyway playing a 2 channel ac3 file shouldn't be a problem though, especially if the 6 channel audio works!

as i said in my prior post already the 2 channel ac3 usually contains either another language or the directors commentary.

steVe

[angelleye]

So then playing an AVI with 2 audio streams...can I select which audio stream I'd like to use. Is that so I could put 2 different languages...or the directors commentary..or whatever...as well as another choice? Or is 2 streams that run at the same time?

Thanks for all your info..

drew

[jggimi]

I'm going to recommend the Audio Encoding (http://forum.doom9.org/forumdisplay.php?s=&forumid=11) forum as the best place to get these questions answered. I believe most, if not all of your questions have been covered in two "sticky" threads you'll find at the top of the page. The first is the Audio FAQ (http://forum.doom9.org/showthread.php?s=&threadid=7633), the second is the AC3 Q&A (http://forum.doom9.org/showthread.php?s=&threadid=18318).

[BeaterRX7]

I'm still getting used to Gordion Knot - excellent program btw, and I'm never sure which AC3 file to use when encoding. It takes me about a day to encode a DVD to .avi and I wasted a day encoding Akira with the Japanese .ac3 track. How can you tell which .ac3 to use? From the previous posts in this thread I'm guessing you guys just double-click on the .ac3 in your windows desktop and it plays on Windows Media Player or whatever you're using. I have Windows XP and a SB Audigy card with Windows MP as the default player and WinAmp also installed. I haven't been able to hear the .ac3s but the .avis play fine after they're encoded.

[manono]

Hello, and welcome to the forum-

I wasted a day encoding Akira with the Japanese .ac3 track.

Most anime fans would consider it wasted effort to encode anime with anything but the original Japanese track. But to answer your question about how to tell what the different AC3 tracks represent; open the Stream Information.txt file that DVD Decrypter creates, and it usually tells you what's in the different AC3 tracks. Or jusy play the damn things and then pick the right one.

And if you want to switch tracks after having chosen the wrong one, if they have the same number of channels, they'll be the same size and you can just mux in the one you really wanted without reencoding.