I've come to notice that NTSC DVD streams play back more jerky than PAL. Here I'm talking about Film that runs at 24 fps being artificially blown up to 30fps, not real 60Hz video. Apart from the finite framerate of the computer (85 fps), what could be the cause of this?

In reality I get all the source progressive frames (~24 fps). But could their durations be mixed?

The doom9 forums are a better place for such questions, but...

85/25=3.4
85/24=3.541666

The frame repetition patterns will be different. Try 72Hz refresh for 24fps material.


Are you sure you're getting the 24fps cleaning? Ignoring pulldown flags or using telecide/decimate?

Cheers,
David.

My playback software (ffdshow) simply ignores any pulldown flags.

I think the following might be happening: When a frame that should be entirely recreated from pulldown instructions comes, nothing is displayed and the previous frame stays on much longer than it should. In other words, it really is 59.94fps but with some frames omitted. I want to find out if this assumption is true or false.

I asked about this on Doom9 before but apparently there was something wrong with my question.

I think, since video is not synced to the display, (fps*n) Hz refresh rate won't help. Can't try it now, because Intel integrated video does not have this rate.

how did you figure that?

With the ffdshow OSD that can display movie and decoder FPS maybe?

Cheers, Slipstreem.

Because there are no interlace artifacts and the Windows video renderer told me so (Average frame rate achieved).


Decoder FPS is 29.970 for these files.

It looks to me as though the majority of the problem is coming from having three different framerates. The source framertae, ffdshow attempting to change this to something else and then an unrelated monitor refresh rate, none of which is an exact multiple of the other. I have no idea what the fix is, but my PC went from 'close to perfection' with any input framerate to 'unwatchably jerky' when I changed from a monitor that supported and was used at a refresh rate of 75Hz to one that only supports 60Hz. Nothing I do fixes it, so I now seldom use my PC as a media centre for movie watching.

Cheers, Slipstreem.