Trying to go from 25fps to 60fps with Chronos with a 10 min 10s video, however the output comes back as 10 min 29s, tried with the original file (wmv) and also tried converting it to x264 in handbrake and running it again with the same results. The duration in the mediainfo is correct for the original file and shows the longer duration on the output file…
Any ideas? (Slow motion is set to 100%, FPS is set to 60)
(Had this happen with multiple videos too)
When I contacted support, it seems that I am currently aware of this issue.
It seems to be a trouble that occurs when duplicate frames are included.
I hope it will be improved in the next chronos model.
Hmm I’ll see if theres duplicate frames and trim them and see if it helps 
Tried generating a new version with ffmpeg decimate to remove duplicate frames… seemed to remove some (dropped the framerate to 20fps), ran Chonos again and the output was even longer… so… no idea
The current version of the chronos slo-mo model doesn’t seem to work unless it’s 2x4x…
Probably due to 3x from 20fps to 60fps
Ah… that explains it, tried 25 to 50fps and it had the correct times. Hope it gets fixed soon!
I have created a procedure to solve this problem (23.976> 59.94 or 24> 60).
1 --Make the post-deinterlaced video (I’m using avisynth QTGMC) at 30fps with assumeFPS.
2 --Convert 30fps video to 120fps with Chronos slo-mo.
3 --Set 120fps video to 96fps with assumeFPS.
4 --Use avisynth “srestore” to thin out frames to frate = 60.
(In most cases, after this process, execute “ntsc_double” in assumeFPS)
This method is, frankly, very stupid, but currently there is no choice but to do it.
Please solve the problem of magnification other than 2x4x as soon as possible.
In the current Slo-mo model, there are many blend frames because there is no scene change detection.
Therefore, flowflames RIFE is used to convert the original source to 60fps, and upscaling is performed with VEAI.
I have a related question - I have a video file that is perfectly looping - that is, the last frame transitions perfectly to the first frame - when I embed this video online it loops perfectly (it’s a Cinemagraph). It’s a 30fps video. When I run this through Chronos and set it to 1/2 speed it looks fantastic, but it’s also doing something to the first and/or last frames, so you can see a “jump” at the loop point.
My request would be to have a checkbox to maintain the first and last frames, which would fix this.
“video output is longer”
I’m having the same issue. See:
https://www.reddit.com/r/TopazLabs/comments/vx8gj2/chronos_is_not_outputting_the_correct_number_of/
Does Flowframes work properly? How about RIFE-app (limited to 2x, 4x, 8x)?
I found this thread:
https://community.topazlabs.com/t/chronos-scene-change-detection/29322
kjell wrote:
“Chronos should be able to detect scene changes and not try to interpolate them, it often leads to weird results if Chronos trys to interpolate between two frames that have no features in common.”
If Chronos is not detecting scene changes, that could be the cause of the issue. I watched what it does when a scene change happens, and it does indeed generate an extra frame for each scene change. This is a major bug and makes Chronos not usable for many projects.
Can someone else report the bug? I have not renewed my support due to job loss. Not that it matters for me… I’m stuck on VEAI 2.3 until json support comes back. I’m going to try Flowframes.
Flowframes is very poor (on this video). Installation was extremely difficult. Python and all the extra packages are supposed to be installed with the installer. They were not. I had to follow instructions (on a different webpage) to download and install Python. The setting of the path variable is not the default, not mentioned except in a forum thread, but very necessary! Then I opened a Adminstrative CMD prompt (Administrative CMD is NOT mentioned in the instructions, only CMD), copy and pasted two cryptic lines that look like they would only work on Linux, not Windows 10, which downloaded about 10 more packages for Flowframes to work. I rebooted between each step. I know for one that Path variable changes do not take effect until reboot. Whew!
And the output is poor. It morphs objects every time a strobe flashes. Not acceptable. Chronos handles strobe flashes perfectly. The only good thing I can say is Flowframes is fast. It took maybe 8 hours to process a 67min 1080p 24fps video. It only handles 2x, 4x, 8x fps increases. I was under the impression it could do 24fps to 50 fps. It has a plethora of output options and Prores output works well.
There’s RIFE-app to try which uses a different algorithm but I don’t know if scene detection works.
https://grisk.itch.io/rife-app
I’m going to try dregist’s workaround (above) for Chronos, but I don’t understand it, or how it could remove extra frames from each scene change.
Would you explain in detail the workings of your process?
Like why is assumeFPS used in step 1?
Why add additional interpolated frames in step 2?
Step 3’s purpose?
After reading the Srestore wiki, it seems that’s all you’d need. Plus AssumeFPS at the end if outputting to a file (vs. png sequence). Can you provide the text of the actual scripts you use? That might help a lot to use and understand your process.
Chronos is by far the best interpolater ever made IMO. I’ve tried all I could find now, those in professional tools, and older scripts from doom9. None come close to the output quality of Chronos, which my strobing poorly lit video requires.
Srestore didn’t work for me. It just outputted blended frames.
I ended up using Chronos at 2x to give 48fps. The frame count is exactly double as it should be. There is a blended frame with each scene change. It’s not visible at 48fps and I’m ok with that.
The developers for FrameRateConverter, SVPFlow, Davinci Resolve’s flow feature, Flowframes, RIFE-app, and others should study Chronos’ algorithm, as it’s superior with videos having poor lighting.
I’m watching the final video for my project and it’s amazing that there is nothing but dim lighting with a continuous volley of strobe lights and Chronos doesn’t blend any frames (other than the scene bug). If anyone is curious, look up Chvrches Hollywood Cemetery to see how bad the lighting is (I’m working on the audio now and the remaster will be at the usual places when I’m done).
