QTGMC framerate changing?

[killerteengohan]

I am using QTGMC to deinterlace a source because TIVTC would not remove all of the lines in some spots while QTGMC does it perfectly. The motion seems to be smoother as well when the entire screen is moving.

The only issue I am having is the final output video is 59.940fps.

When I use TIVTC its 23.976fps.


Why am I getting more frames in my output from QTGMC. Can I keep it at 23.976fps when using QTGMC?

[killerteengohan]

I just read that by default it's supposed to do this apparently unless you add in fpsdivisor=2 to its settings. I tried that and it seems to go to the original 29.97fps of the DVD before it's been deinterlaced instead of 23.976fps, but it's deinterlaced well. I guess it keeps the original framerate of the video its processing when that setting is specified.

So I tried it like this, that way it was processing 23.976 IVTC'd video.

LoadPlugin("C:\Program Files (x86)\MeGui\tools\avisynth_plugin\TIVTC.dll")
tfm(order=1).tdecimate(mode=1,hybrid=0)
QTGMC(preset="slow", fpsdivisor=2)


It seems to have gotten rid of the leftover interlace lines IVTC didnt in some frames and kept the 23.976 framerate as I'd hoped.

I'm skeptical about doing it this way though. Wont using 2 deinterlacers like that just hurt the video?

[killerteengohan]

I guess it does. Set up that way its keeping the original fps of 23.976, but its dropping every second frame essentially making more jumpy.

Apparently I will have to make due with this. This seems to work fine.

QTGMC(preset="slow")
changefps(24000, 1001)


I do however like the smoother movement motion of the 59.940fps version where it was just QTGMC by itself. It doesn't seem jumpy at all and is a smooth glide when the entire screen moves.


Is leaving the video at 59.940fps a bad thing?
I was under the impression that encoded video had to be 23.976fps, 25fps, or 29.97fps.

[Skiller]

Why am I getting more frames in my output from QTGMC. Can I keep it at 23.976fps when using QTGMC?

Because QTGMC is a deinterlacer. That means it interpolates the missing lines in each of the two fields contained in one source frame in a clever way to make each field a frame, hence the field rate of the source becomes the new frame rate; or to put it differently, the frame rate of the source is doubled. This is how you would see the video if you watched the DVD on a TV.

Inverse Telecine is not deinterlacing. What IVTC does is, it matches the fields so that they make up frames and then throw out the superfluos (duplicate) frames so that you are left with the original 23.976 fps. This works only if the source was clean 23.976 to begin with.

If your video can be IVTC'ed nicely, do it. If not, a sane way to deal with it is QTGMC and 59.94 fps.

QTGMC(preset="slow")
changefps(24000, 1001)

Scratch that it's perfectly producing rubbish.

Is leaving the video at 59.940fps a bad thing?

No, not at all.

I was under the impression that video had to be 23.976fps, 25fps, or 29.97fps.

You were wrong.

[jagabo]

Many video containers can contain video with any framerate. Some, like MPG, are limited to particular frame rates. DVD and Blu-ray have frame rate limitations.

If your source is video camera based it may well be 59.94 fps (29.97 interlaced). In that case you wouldn't want to use TFM().TDecimate(). QTGMC() to 59.94 fps would be perfectly fine unless you have a playback limitation (some older devices or slow computers can't handle it). If that causes playback problems use ChangeFPS(30000,1001) to reduce it to 29.97 fps. That discards every other frame leaving less smooth video, but smoother than 23.976 fps would give you.

TFM() sometimes misses some light combing, even given sources with perfect 3:2 pulldown. In those cases you can adjust the cthresh parameter. Sometimes you need to adjust the mode parameter too.

Then there are cases where you have blended frames from PAL/NTSC conversions. Those need to use {QTGMC() or Yadif(mode=1)} followed by SRestore() to remove the blended frames, leaving 25 fps or 23.976 fps (or some other frame rate).

Post a sample of your source if you can't figure out which method to use.

[killerteengohan]

Here is a small sample video from the source.

https://mega.nz/#!EowwxLwY!NI9gKkrWyrOtrU0IMDmhBfqo1GuYyrLPafal-X4Vbvc

[LMotlow]

AssumeTFF()
QTGMC(preset="very fast")
sRestore(frate=24)

[jagabo]

That clip wasn't the best because all it had was slow vertical panning along with the frame blending. Deinterlacers get confused by the thin horizontal lines. But it looks like QTGMC().SRestore() with frate=24 or 23.976 is right.

[killerteengohan]

Thanks!

I can give another clip if you would prefer

[jagabo]

A long horizontal panning shot would be good. Or just run the script yourself and step through frame by frame at such a shot. See if there are any missing or duplicate frames.

[killerteengohan]

I'm trying the script and letting it run now.

In the meantime, is this any better?

https://mega.nz/#!pwJimL5Z!mfNpY84Puu4dcI47RcX80E0Wvkl9OI29novqOzScy_o

[jagabo]

That's a much better sample. 23.976 looks good to me. Note that the difference between 23.976 and 24 is only one frame every 1001 so it's very hard to tell the difference. But it's definitely not 25 fps.

[dannyboy48888]

The QTGMC and srestore option work great. One case use I had was doctor who season 5 bluray which was hard telecined to 60i for the US. I used QTGMC and srestore to 25fps progressive. another example of the combo working great was ducktales that was 60i on some eposides. used QTGMC then srestore for smooth video at 23.976fps. on purely interlaced stuff like dirty jobs, mind of mencina, etc it may be better motion wise to leave the 60p video alone unless the target is MPEG2 then srestore at 29.97p will give some non jerky video, but may seem to blur a little on panning scenes but is still "better" than the stuttering i was getting with just decimating to 29.97p

[killerteengohan]

QTGMC(preset=slow)
srestore(frate=23.976)


That worked perfectly and stayed just about as smooth as the double framerate from just QTGMC alone. Thanks!!



Was that a PAL source converted to NTSC?

[dannyboy48888]

Yes a bad pal to NTSC I did back to pal

[jagabo]

QTGMC(preset=slow)
srestore(frate=23.976)


That worked perfectly and stayed just about as smooth as the double framerate from just QTGMC alone. Thanks!!

A faster preset in QTGMC probably won't hurt much and will run much faster.

[killerteengohan]

Thanks!