I've noticed that the amount of combing present in my videos (I record in interlaced) seems to be correlated not with the frames at any given time of what is being recorded, but rather, the exact point of time I hit "capture".
If I hit capture at X point of in game time (I'm using halo 4's theater mode for a slo mo vid), then nearly the whole video has interlacing artifacts. But if I start recording at Y point in time, the whole video has close to zero interlacing artifacts, even if both videos cover the same period of time/same footage.
This is really annoying, as avidemux can't deinterlace the video without re-encoding it, which would mean visible compression, and though VLC does a great job of deinterlacing while viewing, I can't seem to figure out how to actually get it to deinterlace the file. (Save-convert works, but how do I select the type of deinterlace?).
Attached are four images to show what I mean. Two have clearly visible combing, two do not, but each pair is taken at the same moment of in game time, same frame, just different starting points of the capture session. No difference in what's running on the computer, no deinterlacing, etc.