Easiest way to recognize VFR

[element72]

What is the easiest way to find out if your mkv or mp4 is using VFR?

Regarding mkv I just drag and drop it on to VirtualDubMod and if it argues about the frames, I assume its VFR, but I don't know how to find VFR for mp4

[TheFluff]

Mux MP4 to MKV, do with new MKV as you do with other MKV's.

On a side note, you're asking yourself the wrong question. Matroska doesn't have a segment-wide FPS value; all frames have their own timestamps. Technically all MKV's are VFR and it's just a coincidence that in some of them all frames have the same length. What you should ask yourself is how to determine if the file is CFR, because VFR is normal; CFR is an exception. That said the simplest way to do it is probably to extract v2 timecodes, convert them to the more human-readable v1 using one of several available tools (tritical's avi_tc package being one) and see if there's more than one framerate listed.

[Selur]

iirc mediainfo can report if vfr is used or not,..

[martino]

iirc mediainfo can report if vfr is used or not,..
Indeed. It shows a minimal, maximal as well as average/nominal framerate for VFR MP4s (if its CFR you get just one value). Only MP4s however, for MKVs it only shows what's in the "Assume xxx" timecodes line, I think.