NTSC to PAL AVI2DVD keeping AC3 audio

[WhipHubley]

OK, here goes...

I have an 23.976 FPS AVI with AC3 5.1 audio. I wish to convert it to a PAL DVD, keeping the AC3 5.1 audio.

For the video side of things I just check "NTSC to PAL" in AVI2DVD (which uses AssumeFPS in its AviSynth script) and for the audio side I edit the .d2s file, replacing the encoded audio filename with my extracted AC3 filename (as in Q.74 of the FAQ). This instructs bbMPEG to mux together the video with the AC3 file.

Before doing that of course I need to convert the extracted AC3 file from 23.976 to 25. This way the audio and video will be in sync. For this I use BeSweet which uses ac3enc.

The final result is always perfect when I do this, but the fact remains that the AC3 audio AFTER running through BeSweet sounds nowhere near as good as before.

Because there is no other tool I know of to re-encode the audio and keep it as AC3, I thought it best to keep the original extracted audio and work on this problem from the video side of things. That is, converting the FPS without changing the length of the video. That way I can just mux it with the original extracted audio.

I initially tried "convert to FPS" in VirtualDubMod, but the resultant video is very jerky. So I then looked into ChangeFPS and ConvertFPS with AviSynth, but have read that ChangeFPS will also result in a jerky file and ConvertFPS can be blurry or flickery :-(

I see that AssumeFPS has a sync_audio parameter, but this can only work with PCM audio right? I certainly get errors if trying to use it on an AVI with AC3 audio.

Are there others out there who have dealt with this? I can imagine it's a problem that must have troubled someone else at some point, and I'm hoping they have an answer!

The only other option of course is to convert it and keep it as NTSC - but I really don't want to do that.

Any help, as always, would be most greatly appreciated.

Thanks very much.

[Nick]

To be honest I don't think there's a way out of this one.
Something has to give - either the audio has to be re-encoded to be in sync or the framerate of the video has to be changed.

Whichever you mess with will lose out on quality.

As for Changefps, Manngo wrote a guide
http://manngo.fw.hu/avi2dvd
which you may wish to try.

Cheers
Nick

[WhipHubley]

Yeah, I think you're right. After posting I realised that I'm just being a bit greedy! DVD down to AVI then back to DVD is a bit silly anyway, so I can't expect perfection. annoying though that is :-)

I'll either just allow them to convert to NTSC and keep the original audio (hey, all of the US seem to be happy with it, so it can't be that bad. certainly better looking than convert or change FPS I reckon) or stick with my original method and convert the AC3 through BeSweet.

funny, comparing the original and converted audio with AC3 filter produces a marked difference. but once I'd authored the DVD's and did a comparison using PowerDVD, the converted audio really didn't sound that bad at all. much more "boosted" than with AC3 filter.

I'll have to check on my standalone player, too.

cheers again.

[Manngo]

Hello!

My guide is not perfect, but can give a good gideline on how to do. I'll correct it in a few days, becouse it gives an oversized result.

A tip: In the guide I used ChangeFPS(25), this couses a bit jumping in the video. According to my friends it is quite annoying. So you can use ConvertFPS(25.000,80,49) instead of ChangeFPS(25). It gave me better results, no blurring, but of course it depends on yor taste.

Any problems occure, let us know.

Manngo

[WhipHubley]

cheers manngo.

I found ConvertFPS(25) to be quite slightly blurry (enough to annoy you as you watch it) and ConvertFPS(25,80,49) to look all wavy and pulsating - like you're tripping or something! I might play with these settings at some point to see if I can improve it.

after comparing the pre ac3 encoded audio with the post ac3 encoded audio on my TV, I'm gonna stick with AssumeFPS and BeSweet for now.

I might badger the ffmpeg team to start developing ac3enc again, or learn to code and have a go myself :-)

[Manngo]

ConvertFPS(25.000,x,49)
where x is the 1/2 of vertical resolution of the cropped source.
This gives me a good result. No wavy or blurring effect can be noticed.