Deinterlacing Question

[hizzy7]

Hi folks,

I have been tinkering with the audio in besweet and I found something interesting that I hope you guys could explain to me. I transferred my video to NTSC speed in AVIsynth, and I have been having the toughest time syncing the audio to the ntsc video. When I used the PAL to NTSC preset in Besweet, the audio was messed up. It had a run time of one second less than the video and it was noticeably out of sync. It did not drift out of sync. It was continually out of sync, and badly out of sync. It also sounded weird, perhaps slightly out of pitch, if that makes sense. While playing around in besweet, I decided to try a custom frame rate for the audio Pal 25 fps to NTSC 23.790, not 29.796. The result was perfect. Can anyone venture to guess why? In my avisynth script, I used this:

AssumeFPS("ntsc_film")

Would avisynth interpret that as 23.790? I would love to understand why the NTSC 23.790 in besweet worked so well!

Thank you again for your help and patience!

h

[sanlyn]

"ntsc_film" in the SssumeFPS() command is the same thing as specifying 23.972 frame speed, which is movie nfilom speed. Another way of doing it is to use the command this way:

AssumeFPS(24000,1001)

which is the long way of doing it, meaning take the number "24000" and divide it by 1001, which equals 29.970. "ntsc_film" is a pre-set expression meaning the same thing. It is listed in the Avisynth online help on the internet and on your computer in Avisynth's installed documentation. Click "Start" and go to your Programs listings, find the Avisynth program group, expand it, and click on "Avisynth Documentation".

The same information can be found on the internet. http://avisynth.org.ru/docs/english/corefilters/fps.htm

[LaKap]

"ntsc_film" in the SssumeFPS() command is the same thing as specifying 23.972 frame speed, which is movie nfilom speed. Another way of doing it is to use the command this way:

AssumeFPS(24000,1001)

which is the long way of doing it, meaning take the number "24000" and divide it by 1001, which equals 29.970.

I believe you mean 23.976 for "ntsc_film".

[sanlyn]

Yep. I'll correct that.

[hizzy7]

Hi,

Any guesses as to why the audio slowed to 29.970 works, but 29.796 didn't? My only guess is that there was a flaw in the source. The clip I was working with was a bad PAL to NTSC conversion. Could the maker of the DVD have messed up the speed of the audio?

Thanks again to the experts here for your help. I can't believe the improvements I have made to videos here with your help.

Best,

h

[manono]

It had a run time of one second less than the video and it was noticeably out of sync. It did not drift out of sync. It was continually out of sync

Out of synch at the beginning and out the same amount by the end? Then I don't understand how changing the output framerate would fix that. My guess is there was an opening delay you didn't take into account. I've done this probably over 1000 times using BeSweet. I often find I have to set a -200ms delay to make it come out right. That plus whatever the delay might have been to begin with might account for it. I've never had to change the output framerate. If it was out a second from beginning to end why didn't you just redo it with a -1000 delay set? Or remove the delay using DelayCut afterwards?

It also sounded weird, perhaps slightly out of pitch, if that makes sense.

Yes, it changes the pitch. It was probably the source that was out of pitch and you fixed the pitch when you made it match the 23.976 video.

[jagabo]

Any guesses as to why the audio slowed to 29.970 works, but 29.796 didn't?

Because 29.97 is the NTSC frame rate, 29.796 is not?

30000 / 1001 = 29.97002997002997002997002997002997002997...

[manono]

Any guesses as to why the audio slowed to 29.970 works, but 29.796 didn't?

Because 29.97 is the NTSC frame rate, 29.796 is not?

30000 / 1001 = 29.97002997002997002997002997002997002997...

Maybe reread his post at the top of this page. I don't think he used either 29.97 or 29.796 (not for the one that's supposedly in synch, anyway), but some 23.xxx framerate. There's lots of confusion and mistyping or typos by hizzy7 in this portion of the thread.

[hizzy7]

Hi!

29.97 worked, and 29.796 didn't. Sorry for the confusion!

[manono]

Hi!

29.97 worked, and 29.796 didn't. Sorry for the confusion!

Oh, my mistake then. But what about this:

While playing around in besweet, I decided to try a custom frame rate for the audio Pal 25 fps to NTSC 23.790, not 29.796. The result was perfect.

And if in that one you really meant 29.97fps instead of 29.976fps, then I don't believe you. Not when you first used SRestore to get to 25fps and then AssumeFPS(23.976) or AssumeFPS(24000,1001) or AssumeFPS("ntsc_film").

So, just what is the framerate of your video now? If it's 23.976fps, how can you claim using 25000->29970 in BeSweet can possibly work? If you made the video framerate 29.97fps by speeding it up and your 29.97fps audio really synchs up, then you messed up big time.

[hizzy7]

Hi manono!

Yes, it was 29.97, not 23.790. Sorry for that. The frame rate of the video is 23.976. I used AssumeFPS(NTSC_Film). I used 29.97 in besweet and it works perfectly. 23.976 did not work. It was the first time I used AssumeFPS(NTSC_Film). I always type in the desired frame rate, rather than type "NTSC_Film". Do you think that could have given me something other than 23.976?

Thank you for your help!

h

[manono]

I used AssumeFPS(NTSC_Film). I used 29.97 in besweet and it works perfectly. 23.976 did not work.

Again, I don't believe you. What you say is impossible. Plus, you're contradicting yourself right and left:

My audio is still out of sync when I do 25 fps to 23.976.

It looks to be off by one second for the entire duration of the movie. I think it is something I am doing wrong.

There you're saying slowing it to 23.976fps did work, except for the one second delay which is easily fixed.

Check the video and audio lengths. What was the original PAL2NTSC DVD length? What is the 23.976fps video length? What is the 29.97fps audio length. Something's not right somewhere. And if you really changed it to 29.97fps, you'd get unlistenable chipmunk voices.

[hizzy7]

Hi Manono & Company!

I decided to go over all my materials so that I can give you folks a proper, accurate description of what I have going on. I have been reviewing everything, and I hope that what I'm saying now makes more sense.

- I had a video that was a poor PAL to NTSC conversion. I used AssumeFPS("ntsc_film") to slow it to 23.976. Using Mediainfo, it says that the video is 23.976.

- I used Besweet, which I have very little experience with. I used the PAL 25 fps to NTSC 23.976 setting to create a new audio track. Now, after looking at the audio more closely, I have found some stuff that has me confused:

1) The runtime of the 23.976 audio is one second shorter that my original audio, and, as previous people have mentioned, the audio gradually drifts out of sync with the video. At the beginning of the video, the audio looks to be okay, but, as the video goes on, it goes out of sync more & more as I approach the end of the video.

2) The audio's pitch seems odd, but that might just be my hearing :P

3) On a whim, I decided to try PAL 25 fps to 23.970 fps in besweet, and that worked. I didn't use 23.976, but 23.970. That has synced perfectly to the video.

I don't know why 23.970 worked, but 23.976 didn't. Is NTSC film 23.976 or is it 23.970? I always thought that it was 23.976.

Sorry for all of the confusion. It would have helped if I would have had my facts straight earlier. I hope this makes more sense.

Thanks again for your patience and help,

h

[jagabo]

Is NTSC film 23.976 or is it 23.970? I always thought that it was 23.976.

It's exactly 24000/1001 = 23.97602397602397602397602397602397602397602397602 3976...

Did you check the frame rate after SRestore()? It may not have been exactly 25 fps.

[hizzy7]

Hi Jagabo,

How would one check the frame rate after SRestore?

Thanks!

[jagabo]

# whatever
SRestore()
Info()
Return(last)
# whatever

[hizzy7]

# whatever
SRestore()
Info()
Return(last)
# whatever

Sorry for being dense, but what would the whatever be? Would that be my dv2 file?

Thanks!

[jagabo]

#whatever = whatever else your script is doing before and after the other lines. I didn't feel like looking back through all the posts and and quoting your exact script. The point is to insert Info() and Return(last) right after SRestore(). Info() will print information about the video at that point of the script, Return(last) will stop further processing. Ie, everything after Return(last() will be ignored.

[hizzy7]

#whatever = whatever else your script is doing before and after the other lines. I didn't feel like looking back through all the posts and and quoting your exact script. The point is to insert Info() and Return(last) right after SRestore(). Info() will print information about the video at that point of the script, Return(last) will stop further processing. Ie, everything after Return(last() will be ignored.

It worked! Everytime I get something to work in AVIsynth I am thrilled. You guys are AVIsynth kings, but I find it such a daunting, complicated program. The result is 25 fps after SRestore. It is 23.9760 after AssumeFPS("ntsc_film"). I have now clue why the audio at 23.970 works, but 23.976 doesn't.

[jagabo]

I have now clue why the audio at 23.970 works, but 23.976 doesn't.

What field mode did you use with DgIndex? Did you use Honor Pulldown Flags? If you used Forced Film did it show 100 percent film when it was done?

[hizzy7]

I have now clue why the audio at 23.970 works, but 23.976 doesn't.

What field mode did you use with DgIndex? Did you use Honor Pulldown Flags? If you used Forced Film did it show 100 percent film when it was done?

I did use honor pulldown flags. I loaded that into AVIsynth. I have never used forced film. Do you find that setting useful?

[jagabo]

I have never used forced film. Do you find that setting useful?

If the DVD is nearly all film (like 99.9%) forced film will cause Mpeg2Source() to output 23.976 fps progressive frames. It's a little faster than Honor Pulldown Flags followed by TFM().TDecimate(), and more accurate.

[hizzy7]

Would using honor pulldown flags effect my frame rate? I know I'm not making any mistakes in besweet. 23.970 works, but 23.976 doesn't, and 23.976 gradually drifted out of sync.

[jagabo]

Would using honor pulldown flags effect my frame rate?

No, it's the most accurate way to work with NTSC DVD video. The other methods (Ignore Pulldown Flags, and Force Film) can lead to frame rate errors because MPG video doesn't always have a constant frame rate before pulldown. But after pulldown it's always 59.94 fields per second (60000/1001).

[hizzy7]

Say if I just wanted to use the original audio and keep the 25fps, what would you recommend I use to make the frame size PAL? I am using Sanlyn's script from post 100. Would I just add spline or bicubic resize?

Thanks!!

[jagabo]

Say if I just wanted to use the original audio and keep the 25fps, what would you recommend I use to make the frame size PAL? I am using Sanlyn's script from post 100. Would I just add spline or bicubic resize?

Yes. Or you could try using nnedi3_rpow2(2, cshift="Spline64Resize", fwidth=720, fheight=576) for slightly better results. If you're not making a DVD there's no reason to resize though.

[sanlyn]

Say if I just wanted to use the original audio and keep the 25fps, what would you recommend I use to make the frame size PAL? I am using Sanlyn's script from post 100. Would I just add spline or bicubic resize?

Aside nfrom the resize matter, there was no audio with the original m2v sample, so there was no way to check it at this end.

[hizzy7]

Say if I just wanted to use the original audio and keep the 25fps, what would you recommend I use to make the frame size PAL? I am using Sanlyn's script from post 100. Would I just add spline or bicubic resize?

Aside nfrom the resize matter, there was no audio with the original m2v sample, so there was no way to check it at this end.

Your script is amazing. I find the results astounding. I just figure that it would be easier to just keep the whole thing at 25fps. Thank you for your help. I will try to encorporate nnedi3_rpow2(2, cshift="Spline64Resize", fwidth=720, fheight=576) into the script. Do you have any suggestions as to how I can make it work best?

Thanks!

[sanlyn]

With the resizing routines, you often have to fiddle with different methods to see which works best. You can have two sets of coded line that resize in two different ways. To disable one routine, just place a "#" comment mark at the beginning of each line you want to disable.

Resize routine 1    # <- this line is enabled.
# Resize routine 2  # <- this line is disabled.

I often do a lot more tweaking than many users. Quite often some levels and color adjustment can make a video look entirely different, apart from denoising and other cleanup.

[hizzy7]

Hi Everyone!

I have noticed one thing that I think might be the key to my problem. When I transfer the audio from 25 fps to 23.976, it sounds like it is slowed down or something. If I could fix that, I think that would solve the problem. Is there a setting in Besweet that I can change? Sorry to manono and everyone for making this so complicated. I feel like I am inching closer to understanding the audio issues here.

Again, thanks for the help,

h