Asynch Ogg-Audio in Divx4.x Movie

[kilg0r3]

Hi there,

What would be the way to go in order to fix asynchronous audio in a movie encoded with divx 4.x with an ogg vorbis audio stream? Streched audio probably would involve creating a temp wav file and its editing in cooledit or sth. like that. Yet, what about displaced audio? For neither virtual- nor nandub can handle ogg-audio.

[Neo Neko]

Quick question. Are you using Vorbis in AVI or in OGG? Vorbis does not work well in AVI. But it does work well in OGG for some reason. ;)

[kilg0r3]

i guess the procedure given below makes it an ogg-stream

1. ripping and encoding of audio via gknot-apps
2. ripping and encoding of audio via dvd2avi and besweet
3. multiplexing via graphedit using the ogg splitter and multiplexer

right?

cheers kilg0r3

PS: i've never understood how streched audio can occur in the first place

[ChristianHJW]

BeSweet can handle audio delay fine on transcoding to Vorbis .... and for other proggies like HeadAC3he you may use AC3delaycorrector ( sorry neither know URL nor precise name .. go search Doom9 downloads for similar name ).

[kilg0r3]

@ChristianHJW

this means that, in order to correct shifted audio, one would have to reencode and mux the audio multiple times in order to get the timing right. the same would apply for streched audio. to me this looks like a very long winded approach.

of course, ogg vorbis is a very young format, and, consequentialy, one should not demand too much of the tools that are able to handle it. still, i would be very glad about a smoother solution.

[ChristianHJW]

So i understand the audio delay is not constant over the whole movie ?

[kilg0r3]

sorry, it seems i've not made myself very clear. :( basically, i'm talking about both possible cases.

problem 1
shifted audio, which means that the delay is the same over the whole movie

problem 2
streched audio, which means that the amount of delay changes between beginning an end of the movie

i've got TWO films here. film A ('the shooting') suffers from problem 1 while film B (ride in the whirlwind) suffers from problem 2.

[DSPguru]

problem one - can be fixed by asserting dealy.
problem two - can be fixed by using FRC.

[MaTTeR]

@kilg0r3

Are you sure it's stretched audio instead of the video? It seems strange to have the audio stretched:rolleyes:

How did you transcode the AC3?

[kilg0r3]

@matter

i know its strange but the frame rate is ok, 25fps. actually the audio is not too long but too short, i.e., in the beginning its o.k. but later it comes too early.
i've extracted the ac3 with dvd2avi and transcoded it to ogg audio with besweet.

@DSPguru

->delay assertion:
is there a way to edit the asserted delay of an existing ogg audio file? for, that would save me from having to transcode the audio multiple times in order to find out the appropriate delay.

->frc:
would a conversion from 25.0fps to 25.003 or is the application restricted to ntsc->pal conversion etc.?

just out of interest, how is a change in the frame rate accomplished?

cheers to all of you for the patience you are having with me

kilg0r3

[MaTTeR]

kilg0r3,

Which players have you used? Are you using Direct Sound or Wave Out as the audio device?

I ask because I've seen this stretch effect before but it was due to have a combination of DS/WaveOut with DeDynamic. Unfortunately I've yet to pin it down on what the problem is. ATM I suspect WaveOut slowly gets out of sync if your playing an AVI with either Ogg or MP3. It doesn't happen with AC3 though.

[kilg0r3]

@matter

don't think its related to any of these factors because the asyncronous audio is specific to these two movies. i've had this problem once with another rip (insider) containing an mp3 audio track. used the avi-information tool to fix it. does no longer work very well under xp though.