how can I fix audio delay with avisynth?

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how can I fix audio delay with avisynth?

Postby mikansei » Sat Apr 02, 2011 3:13 pm

I'm opening a new thread to ask about the audio, because the dehalo thread is getting very long.
I have doubts about working with the audio: I want to put the original audio and a new track.

When I demuxed the audio with DGIndex for the whole episode (not just the sample), I got the value "xxxx T01 2_0ch 384Kbps DELAY -162ms.ac3"

So according to http://www.animemusicvideos.org/guides/ ... dio3b.html I need to keep that delay in mind when synchronizing the episode. OK… now my question is: which script in avisynth will let me correct this delay? I know there is this filter called delayaudio but I don't know if that's the filter I need or how to use it.

Anyway, I will be converting a NTSC DVD to 23.976fps by IVTCing it. My final video will be 25fps as the the 2nd audio track I want to add is a 25fps audio. I will be using Zarx264gui_1.4 to convert the DVD to mp4, so is the following script what I need to convert from 23.976fps to 25fps?

Code: Select all
Delayaudio(xxx)
- IVTC filter
- footage cleaning filters
- resizing & cropping filters
AssumeFPS(25)


I had always used Virtualdubmod until now, so any help will be appreciated! For instance, if you know of any guide/site about editing audio with avisynth or how to convert NTSC to PAL... (that explains how to convert both audio and video, using AssumeFPS, etc.)
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Joined: 21 Mar 2011

Re: how can I fix audio delay with avisynth?

Postby mirkosp » Sat Apr 02, 2011 4:10 pm

You should try to avoid loading audio in avisynth, especially if lossy (ac3 is). Just, when you mux the audio with the video, remember to set the delay correctly again.
As for framerate, it does not matter. As long as the 25fps track wasn't made from a sped up version of the footage, then the framerate at which you should play it back doesn't have to change, so I'd suggest you to keep the framerate at 23.976.
There is a slight possibility that the dub for the PAL version was made at 24.00 or something along those lines however, so you'd either have to slightly speed up the video and ac3 audio to that or slow down by a factor of 1001/1000 the PAL track. Not sure about this one tho as it depends entirely on how the PAL audio was made to begin with...
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Re: how can I fix audio delay with avisynth?

Postby Mister Hatt » Sat Apr 02, 2011 4:42 pm

Don't use PAL sources to start with and you don't have a sync problem. Never handle your audio in avisynth because it's a shit way to do it. Pay attention to delays is all.
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Re: how can I fix audio delay with avisynth?

Postby mikansei » Mon Apr 04, 2011 3:31 pm

>mirkosp
I'm lucky and my PAL audio is 29.796fps! (or 24, dunno yet)

>mister hatt
True. I cannot change my country's video system though lol

Thank u!
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Re: how can I fix audio delay with avisynth?

Postby mikansei » Mon Apr 04, 2011 3:31 pm

@mirkosp: I meant 23.976fps
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Re: how can I fix audio delay with avisynth?

Postby Mister Hatt » Mon Apr 04, 2011 6:59 pm

No, but you CAN change the rates you use seeing as the content was never PAL originally. That's like saying Japan and the US use NTSC so you shouldn't encode at FILM rates.
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Re: how can I fix audio delay with avisynth?

Postby mikansei » Tue Apr 05, 2011 12:45 am

Oh, I see what you meant. Gotcha. Sure, I tried editing in 23.976fps and I could. But in case the audio had been at 25fps I should have changed the video fps to 25fps, is that correct?
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Re: how can I fix audio delay with avisynth?

Postby Mister Hatt » Tue Apr 05, 2011 1:15 am

Audio doesn't have a framerate, as long as the duration matches it makes no difference...
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Re: how can I fix audio delay with avisynth?

Postby mikansei » Tue Apr 05, 2011 6:07 am

oh, got it. thank u!
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