AC3 rather than Mp3

[Wolfman]

I have looked around on here and checked out some answers.. and I have two querys
AutoGK .. it would be nice to have the ability to use AC3 rather than mp3 (at the same bitrate) eg 192k AC3 rather than 192k mp3 .. the ac3 could be either 5.1 or 2.0, so ability to convert 5.1 ac3 to 2.0 AC3 in the program would be needed. Or even 256k ac3.

Also Gordian Knot doesnt allow you to use a lower quality AC3 rather than mp3...

basically I would like to be able to use AC3 rather than mp3 at medium bitrates 192k 265k 320k... is this possible?

I know I could AGK or GK, with mp3 at the same bitrate, then demux the file (mp3+video) then manually convert the Ac3 to lower quality AC3 then remux the file :confused:


Also aspect ratio adjustment in AGk would be nice.. at present I am using 1:1 input PAR GK to adjust for my player.

[jggimi]

Use Gordian Knot:[list=1] Demux the appropriate soundtrack from the vob set with DVD2AVIdg. You'll find it in Start...(All) Programs ... Gordian Knot ... Apps ... DVD2AVIdg, or, on the Ripping tab of Gknot.

Use BeSweet GUI to encode your soundtrack to .ac3 at the desired bitrate. You'll find it in Start...(All) Programs ... Gordian Knot ... Apps ... BeSweet.

Press the Select button in the Audio A box on the Bitrate tab, and select your soundtrack file to account for it's size.

Select the file again on the Audio 1 tab after you "Save & Encode," and select "just mux".[/list=1]

[Wolfman]

Good idea ..
Btw, why does GK take so much longer than AGK? even setting virtualdub on highest priority?

[jimmy basushi]

have you got vdubmod set on fast recompress as default? im not sure if gknot does that itself ?

[DSPguru]

ac3 isn't as good as the mp3 format when encoding stereo is concerened (not to mention that, BeSweet, in particular, uses lame for mp3 encoding which is a superb encoder, and using ac3enc for ac3 encoding which really sux).

therefore, i would suggest keeping an original stereo ac3 track instead of transcoding to mp3, but wouldn't advise to transcode 5.1ac3 to 2.0ac3, but to transcode 5.1ac3 to 2.0mp3 (or ogg.. or aac..).

[Wolfman]

Thank you for your comments Mr Besweet.. and I agree about keeping an original ac3 stereo file. However I just used besweet to try and transcode some ac3 to mp2 and for the life of me I couldnt get it to work..I mean I'm not stupid, but the interface (IMO) needs a thorough going over. :mad:.Why do you say however that mp3 stereo is better than ac3 stereo file?? I have no idea there would be any diff?
besweet, when I can get it to work, is fast tho.. this is all for use on my divxplayer which doesnt use ogg or aac.

[DSPguru]

the interface.. are you talking about BeSweetGUI ?
use the BeSweetGUI wizard mode, it's much friendlier..

anyhow, a general advice would be to read the BeSweet FAQ, always to produce a logfile, and to read the logfile when problems are met.
comparing the specs, mp3 is more advanced than ac3 for stereo signals.
anyhow, the quality of encoded streams is heavily dependent on the specifiec encoder rather than the standard in general, eg, there are mp2 encoders that are better than other mp3 encoders.
as mentioned before, BeSweet's mp3 encoder (lame) achieves much better result than BeSweet's ac3 encoder (ffmpeg's ac3enc module).

[Taurus]

@ Wolfman

It is simply not true, that GKnot is slower -> AutoGk.
Autogk is performing a lot more of testing and averaging as GKnot in manual mode.
Maybe you screwd up your initial settings. To correct this, go to Options, Reset ini, and, or hit delete Registry key.
And look in VdubMod if Fast recompress is set.
But don't blame me if this doesn't work, all your manual settings will also be gone. (I am using GKnot for years and when I feel there is a little sluggish around, I just del my precious settings and build them from scratch).
And be aware that you use the updated Besweet (Download from Webpage of the author), caus the one that came with the original GKnot package is known to be buggy.
Should have been fixed via a silent update in the last Gknot package.
And don't go to more than Normal priority in VdubMod, you only run into trouble, lost frames, lost house, lost girlfriend, lost windows:D
As one wise man said: 95% of failures are made by human, the rest depends on bad material and Micros......

[Wolfman]

Alright sorted the probs with besweet .. installation got corrupted .. so re-install let everything work.
re speed.. AUTOGK gets 15-30fps when doing main job of work in virtualdub..fine thats about what I expect
GK gets about 3-4fps :confused: when doing main encode in virtualdub, It sounds like you are right re fast re-compress but as far as I know GK (not much), it sets this itself or is there some sort of settings file?

Yes I am referring to besweetGui.. non-standard things can be nice but..:rolleyes:

[jggimi]

Wolfman: Both AGK and GK use the same application, VirtualDubMod, to do the video encoding. However, what they encode may be different. You can see the difference by comparing the .avs scripts used for encoding. Resolution, noise reduction, and other differences can have huge impacts. In addition, the bitrate used can effect elapsed performance as well.