Audio Slow after NTSC>PAL...?

[nbarzgar]

Hello,

I have converted an .avi-file from NTSC to PAL, following this guide:
http://www.johnisme.shawbiz.ca/avi.shtml

Everything works fine, like a charm actually, but the audio-playback of the resulting file (i.e. PAL-standard) is slightly slower than the NTSC one.

I know that the two framerates (here it was 29.97 NTSC) are different in playback-speed as the fr suggests... but I have done one or two such conversions before and did - thanks to BeSweet's excellent template - have no such problems...

It makes voices and speech sound a bit too slow, as if the actors had made it a point to speak more slowly; although pitch is untouched, thanks to BeSweet again.
So
- do I imagine this,
- is it to be expected in such cases, or
- may I just be to particular...?

Thanks for any instruction on this point.

[Baldrick]

29.97fps to 25 will sound slow yes. Maybe your last conversions was from 24fp to 25?

[manono]

What was the AVI framerate? If 23.976fps you screwed up. That guide says nothing about converting the audio using the 29.970->25.000 Preset in BeSweet.

[nbarzgar]

Thanks for fast replies!

Well, I did 23.978>25.000 before...

Would make indeed some difference, as I think myself now, wouldn't it?

I just thought in terms of format (NTSC/PAL), but of course from 23.xxx to 25 is fastening the pace, so to speak, whereas 29.xxx>25.000 sloows down, right?

So it was my misreading/not thinking properly. Well, no real harm done. The originals are there...

Have you got any better suggestions by any chance to prevent jerky playback of NTSC material (in this case 29.xxx!) on PAL-player/TV?
Would I have to encode again to achieve that?
Thanks again!
EDIT: Just looked again and found SatStorm' guide. I'm quite used to using AviSynth and just this minute trying out Donald Graft's tutorial on "Telecide" inside Decomb. So will try that and report back. Preview so far looks promising...! EDIT

@manono

That guide says nothing about converting the audio using the 29.970->25.000 Preset in BeSweet.

Well, in fact it does, but only in terms of format. At the bottom of the page, refer to "Step 4"... BUT as both of you pointed out correctly, it says nothing about 29.xxx ...mentions 23.xxx only

[manono]

Well, in fact it does

Well in fact it doesn't. The whole of part 4 says:

Step 4:NTSC to PAL Conversion
For ntsc to pal conversion just enter 25000 for the video frame rate in
virtualdub and for besweet choose the preset NTSC -> PAL (23.976 to 25.000).

Nothing about 29.970->25.000. If this thing is a movie, and if the source framerate is 23.976fps, and if you're converting to PAL's 25.000fps, you use the 23.976->25.000fps Preset.

Have you got any better suggestions by any chance to prevent jerky playback of NTSC material (in this case 29.xxx!) on PAL-player/TV?

That's a little vague for me to answer. If you're following that guide, and if I'm understanding you correctly, then that guide is dead wrong when it says:

Then load the m2v that you got from demuxing and browse and open with dgpulldown and choose the desired fps,if the file was pal-ntsc then the selection would be 25-> 29.97,for ntsc to pal it would be custom
23.976->25 or 29.97->25 depending what the original fps was.

You can't apply DGPulldown to get a lower framerate than the source; you can't apply DGPulldown for 29.97->25. I don't think the guy ever tried as it'll be rejected. If you have a true 29.97fps source (AVI or whatever, and not telecined from 23.976fps), it's nearly impossible to get a smooth playing 25fps PAL result. Unless you're willing to blend the heck out of it. But you can probably get a much better result than you're getting now, I think. But you haven't detailed what you're doing, and I'm not sure I understand your question anyway. If you're unsure of what you have and how to treat it, you could always upload a 10 second clip of it for us to have a look.

[nbarzgar]

Well, in fact it does, but only in terms of format. At the bottom of the page, refer to "Step 4"... BUT as both of you pointed out correctly, it says nothing about 29.xxx ...mentions 23.xxx only

My way of expressing myself was a bit involved/confusing, it's what I meant...

Have done several test-conversions. The following yields the best results (no jerkiness of playback, clean and nice audio):
1. AviSynth Script (After all ):

DirectShowSource("D:\path-to\movie.avi")
ConvertToYUY2()
ConvertFPS(23.978)

I load the script into VdubMod, where the audio (as is the case in AviSynth) is shown as "Wav PCM". That way, it seems, the audio is processed flawlessly - using compression into original codec for video (DiVX).

2. I plan to use BeSweet, etc. afterwards, as per the above mentioned guide.

That means:
1. 29.97 (DiVX-video, AC3-audio in .avi-container)>23.98 (DiVX+wavPCM in.avi)=video re-encoding
2. 23.98>25.000 (DiVX+mp3/AC3-audio)=fr-adjustment+audio-encoding (s. guide)
CU

Thanks again for your kind help and suggestions!

[manono]

ConvertFPS(23.978)

Yes, that's what I meant when I said, "Unless you're willing to blend the heck out of it."

However, if you're satisfied with the blurry (but smooth playing) video you're creating , then that's the way to go. I might make a couple of more suggestions, though. If you are OK with keeping the video the same length - not having to speed it up or shorten it - then you can just make it ConvertFPS(25) instead. You can do it in one shot. The video stays the same length and the original AC3 audio can be kept without doing the time-stretch.

Even if you prefer to do the time-stretch for some reason I can't begin to fathom, you can do it all in one crack like this:

ConvertFPS(23.978)
AssumeFPS(25)

And by the way, it should be:

ConvertFPS(23.976)

Depending on how long the video is, by having that last figure off by a little bit, you may find the audio drifting off by a little bit by the end. Unless that's just a typo. And all this assumes you have a true 29.97fps source, and not some 23.976fps source improperly converted to 29.97fps by some idiot that didn't know what he was doing.

[nbarzgar]

Hi manono,

thanks for all the kind help, again...

Indeed I have now done two files the way you suggest, as it occurred to me also, why not try the short way...

Works fine! Faster too and less troublesome! I feed the script into Total Video Converter and on the TV screen (10 years old, not the height of sophistication... ) the outcome is great (I didn't trouble about file length, since that doesn't bother me...)

Script:

DirectShowSource("D:\path to....avi")
ConvertToYUY2()
ConvertFPS(25.000)

(I like using DirectShowSource since ffdshow is called then and the image is just that little bit crisper.)

Of course - this is NOT, as you point out - the best way to go, if best possible quality of image is to be kept... But these files are not of such grave importance, and I am (s.a.) quite satisfied this way.