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View Full Version : deinterlacing progessive video?

draggoon01
13th March 2005, 19:43
if you're doing a conversion and run a deinterlace filter on a video that is already progressive, will that have any negative affects on the output?
stephanV
14th March 2005, 00:03
a "smart" deinterlacer should not detect any interlacing and therefor not doing anything, with "dumb" interlacers your video just gets blurred. But i don't really understand the question, why would you do that?
Leak
14th March 2005, 00:28
Originally posted by stephanV
a "smart" deinterlacer should not detect any interlacing and therefor not doing anything, with "dumb" interlacers your video just gets blurred. But i don't really understand the question, why would you do that?

Well, this would be one way to handle 29.94 FPS progressive material that has bits of 23.976 FPS material with 3:2 pulldown interspersed in it so you can watch it on a non-interlaced display or encode it as progressive - then again I'd really use Telecide or TFM in that case...

np: Digitalis - Rentrer (Snarecrisp Mix) (Silent Season Dub)
draggoon01
14th March 2005, 01:16
Originally posted by stephanV
a "smart" deinterlacer should not detect any interlacing and therefor not doing anything, with "dumb" interlacers your video just gets blurred. But i don't really understand the question, why would you do that?

to answer why, i transcode videos i download to mpg4. sometimes the videos are interlaced, sometimes not. it'd be convenient if i could just load one processing settings for all the videos.

is the internal deinterlace filter for virtualdub "smart"?
stephanV
14th March 2005, 09:50
no, the internal deinterlacer just blends. use smart deinterlace from neuron2; it has a motion threshold, to set the sensitivity of the deinterlacer (the lower the threshold the more likely it is a frame will be deinterlaced)

Why dont you just create 2 scripts, it would be a cleaner solution.
kassandro
27th March 2005, 19:59
Originally posted by stephanV
a "smart" deinterlacer should not detect any interlacing and therefor not doing anything, with "dumb" interlacers your video just gets blurred. But i don't really understand the question, why would you do that?
Unfortunately this is not correct. A smart deinterlacer interpolates/blends only those areas with motion. Of course, progressive video usually also contains motion. Thus smart deinterlacers alter progressive video as well. Moreover, most smart deinterlacers, base the decision to deinterlace or not, on thresholds and one may generate threshold artifacts, which are not compression friendly.