Twixtor “Pause” Problem

Barry W. Hull wrote on 6/18/2013, 9:08 PM
If someone has experience with Twixtor and can solve this problem I would be thankful.

I have used Twixtor with other files without issue, but now it seems that there is a “delay” every second or so, the motion simply pauses briefly and then continues. This repeats over and over.

I have other files on the timeline that render as they should, the only problem is the track with Twixtor.

Please take a look at these files, maybe someone has seen this problem before.

The “regular motion” file is from Video Blocks. Unless you have a membership I’m sure it is copyrighted, please don’t use it except to help solve this issue. I know you know that, thanks.

The “slow motion” file is the one I rendered using Twixtor.

I’ve wasted almost an entire day trying every setting I can imagine, no luck, any help, thank you.


Grazie wrote on 6/19/2013, 1:36 AM
Eh? I often use TWIXTOR - I've not had this. It's as if you have a "pause" KF on each and every pass.

I'll have a go.

1] Do a G-Spot on that VideoBlox file. What is it?

2] Do a Pre-render to a "known" workable file type.

3] Repeat your TWIXTOR.

I'm not sure if this has any relevance, but do you have disable resample applied? Meaning NO resampling?

Barry W. Hull wrote on 6/19/2013, 6:42 AM

1] I must not get out of the house enough because I always though G-Spot meant something else, not sure what you mean by that.

2] I tried rendering to a workable file type, Mainconcept MP4 (AVC), and then using Twixtor on that, no luck.

3] I tried all the combinations of resample, with no luck.

I reinstalled Twixtor, no luck with that either.

Twixtor seemed to be working great, and then all of a sudden...
farss wrote on 6/19/2013, 7:38 AM
That's a significant amount of slowing down going on there but at the same time I cannot see anything in the video that should challenge Twixtor too much at being able to pull it off.

Have you tried going back to a clip you've previously been able to process through Twixtor without issue?

Barry W. Hull wrote on 6/19/2013, 8:35 AM

I redid a clip that had worked, and it still worked.

Some clips I slowed way down to 3%, worked OK. The sample clip with the "pause", I slowed to 10%. I also tried it at 50%, the pause was there, but it was shorter in duration.

It seems that some clips work, and some don't, and I am unable to determine why... big frustration with Twixtor. I sent tech support an email (no phone number), we'll see.
Grazie wrote on 6/19/2013, 9:07 AM
Thanks Barry. I'm interested on the outcome from tech at RE:vision.


Barry W. Hull wrote on 6/19/2013, 2:05 PM

Here is the response from Pete at Twixtor:

"Okay, the answer is easy. The original footage has duplicated frames in it. If you step through the original footage, you'll see that every now and then there are two frames that are the exact same picture."

Does anyone know of a simple, automated, way to remove every 5th frame?

As it is now, I take the time to find a suitable background, which is very time consuming, only to find out that it doesn’t work.
Barry W. Hull wrote on 6/19/2013, 2:28 PM
I spoke with Video Blocks, where I got the original footage.

I was told that they convert everything to 29.97fps, so if it comes to them as 24p, they are going to render it up to 29.97, creating this problem.

... another gotcha in the world of video.
Grazie wrote on 6/19/2013, 4:17 PM
Thanks for passing this on.


john_dennis wrote on 6/19/2013, 6:59 PM
'[I]Does anyone know of a simple, automated, way to remove every 5th frame?[/I]"

Start here.
johnmeyer wrote on 6/19/2013, 7:07 PM
Does anyone know of a simple, automated, way to remove every 5th frame?I do this almost every day. There are several ways to do it, but I use AVISynth with a plugin called TIVTC. You said you want something simple, and while I find AVISynth simple, it is pretty geeky (like me) and not something everyone feels comfortable using. If you don't want to use it, hopefully other people may have easier-to-use recommendations.

The technology that does what you want is called "inverse telecine" software, sometimes abbreviated "IVTC." You can Google this and perhaps come up with something that you might want to use instead of AVISynth.

The procedure for doing what you want is actually a little more complicated (usually) than removing every 5th frame. This is because "telecine," which is the act of duplicating in order that your 24 fps material can play at the proper speed on a device that expects 30 fps (nominal, actual = 29.97 fps), actually does not duplicate entire frames, but instead duplicates fields. This produces a much smoother result because you only get half a duplicate every 1/60 of a second instead of a full duplicate every 1/30 of a second. So, to do the inverse telecine, the 29.97 video is first split into its separate even and odd fields, and then the software looks for fields that have been duplicated.

For simple telecine (which is what you have), here is the AVISynth script that will recover the original 24 fps footage. In my experience, this software performs perfectly, with no residual duplicates, and without deleting anything that isn't a duplicate.

AVISource("e:\my video.avi")

Barry W. Hull wrote on 6/19/2013, 8:16 PM
Thanks for those suggestions. You're right, it's pretty geeky, my head almost exploded reading about it, but I'll keep trying.

I manually deleted each duplicate frame in a 15 second clip, took forever, but it worked, Twixtor was smooth as silk.

But I need something quicker... now if I can figure out AVISynth...
johnmeyer wrote on 6/20/2013, 12:02 AM
If you can post a short clip somewhere, I can take a look to make sure that it contains duplicate frames, and not duplicate fields. If you delete frames, but the telecine was done by duplicating fields, you may still have residual problems.

I can do this stuff in a matter of a few minutes, so if the clips are relatively short, I'd be happy to remove the pulldown from them.

Oh yes, this process is also called "pulldown removal." If you Google that, you may find some additional tools you can use, including Final Cut and After Effects.
amendegw wrote on 6/20/2013, 5:26 AM
"now if I can figure out AVISynth"Barry, A little better than a year ago, I put together a series of tuts for Rory Cooper for the using AVISynth & MVTools2 for SloMo. It was rather specific to Rory's needs (e.g. Vegas 10 32 bit & MVTools2 vs. TIVTC), but if you have an hour or so, the following might give you an idea of the steps needed to run johnmeyer's recommendations.

Good Luck!

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Barry W. Hull wrote on 6/22/2013, 5:51 PM
John, Jerry, thanks. I will explore AVISynth... However, I heard from Videoblocks. Turns out their MOV files remain in their original format, so it will not be an issue when slowing down using Twixtor. They offer download in both MP4 and MOV.

The only problem files are the MP4 that were originally recorded in 23.97 and then converted to 29.97.

So anyway, if anyone gets that "pause" when using Twixtor, it is probably the source file, every fifth frame or so there is a repeat.

Yeah, I had gotten myself all pumped up to use AVISynth, now I can go back to sleep.
Grazie wrote on 6/22/2013, 10:42 PM
Barry: "So anyway, if anyone gets that "pause" when using Twixtor, it is probably the source file, every fifth frame or so there is a repeat.

Hence my invitation for you to use G-Spot. This is a great free media analysis tool. I use this all the time when I'm needing to see what is inside the "wrapper" of a piece of media. 2.07a (last updated 2007)[/link]


Concerning MediaInfo, I like this BBC comment!:



johnmeyer wrote on 6/23/2013, 1:45 AM
G-Spot is a completely useless tool for this particular problem because it has no way of knowing whether a video stream contains duplicate fields ("pulldown"), or not.
Grazie wrote on 6/23/2013, 4:08 AM
I wouldn't say "completely". Not from the outset. It would have told our colleague that it was of a frame rate or another. Was he even sure it was pull-down? What I read was this: " . . . but now it seems that there is a “delay” every second or so ".

I'm real glad I offered it to him as it may assist him with other issues. But that's the kinda guy I am.


Barry W. Hull wrote on 6/23/2013, 9:09 AM
Thanks Grazie, I will add that to my bag of tricks.

... and finally I know what G-spot is.
johnmeyer wrote on 6/23/2013, 2:06 PM
I wouldn't say "completely". Not from the outset. It would have told our colleague that it was of a frame rate or another. Was he even sure it was pull-down? What I read was this: " . . . but now it seems that there is a “delay” every second or so ".I am not being critical of anyone's attempt to help someone here in the forum. However, I think it is important to point out that you cannot get any information about pulldown cadence from GSpot, Mediainfo, or any other tool that reports information from the header of a video file. This is important because if anyone has a future problem with Twixtor, or any other problem that results from dealing with video files that contain embedded pulldown fields, they should not expect to get any help whatsoever from these tools, and should not use them for that purpose.

Instead, you either need to use the "trick," documented many times in this forum, to deconstruct a video into its component fields and then observe the field-to-field motion as you walk through the video one field at a time, or else do the same thing using an external tool like AVISynth. Even with the amazing tools available within AVISynth (or VirtualDub), there is no automatic way to determine what is going on: you have to do it yourself by going from field to field and looking for lack of motion between adjacent fields, and then writing down how often that happens. The lack of motion is a pulldown field that must be removed. Once you know the cadence of the pulldown, you feed that information to your IVTC software, and if you set everything up correctly, you will end up with the original progressive source.

Finally, just to complete the thought, you should always remove pulldown before doing any editing or encoding. Failure to do this will seriously degrade the result.
Grazie wrote on 6/23/2013, 3:04 PM
Thanks John.