What's the best way to convert Variable to Constant Framerate nowadays?

[Dagger7]

I've got some old recordings when I didn't know anything about video. What's the best way to convert them nowadays?
I use avidemux for cutting and converting video and audio streams. Is it good for this task or there's a better tool out there?

[hello_hello]

To convert a VFR to a CFR it's necessary to duplicate or delete frames, or some combination of the two. If you need to convert to a CFR (why bother though?) it's best to pick a frame rate high enough so that frames are only duplicated, not dropped. For an NTSC DVD VFR encode (as an example) the peak frame rate will oftem be 29.97fps, so you'd use that as the new constant frame rate.

IMO, the best way (maybe the only way) to successfully convert from VFR to CFR is to decode using a method that can convert the frame rate as the video is being decoded. I'm not all that familiar with Avidemux but it has a "Resample FPS" that looks like it might be what you need. If not, it's do-able in Avisynth if you're familiar with it.

Maybe try the Avidemux filter first and post back if it doesn't do the job and you want to try another method.

[ProWo]

If the video can be played correctly, there is no reason to convert VFR to CFR (you only lose quality).
If your video is a mp4 video, a simple remux to another container format (e.g. mkv) may help. Often a video stream in an mp4 container is not VFR at all, but actually CFR.

[abolibibelot]

If your video is a mp4 video, a simple remux to another container format (e.g. mkv) may help. Often a video stream in an mp4 container is not VFR at all, but actually CFR.

In the past I've had an issue playing a "VFR" flagged video on a standalone BRD player ; simply remuxing with mkvmerge or ffmpeg or mp4box did not do the trick. Setting the framerate while demuxing with TSMuxer, then remuxing with mkvmerge, did the trick.