softskip vs decimate for 720p

[morph166955]

I just spent the better part of my night running tests on this weeks episode of house which i recorded using my fusion5hdtv usb into an MPEG-TS .tp file. Once i got the bugs all worked out of my scripts i began plaing with the video filters because my videos were semi choppy. first thing i did was to scale the video down using "crop=1280:704:0:10,scale=720:-2". this helped greatly but not completely. i then went to add -ofps 30000/1001 (i figured going to 30fps over 24 was right because this was originally a tv show and not a dvd movie, if im wrong let me know). having this string of ofps and vf worked mostly but i was getting very jumpy video. alot of places on the net recomended using decimate=2:1000:1600:.001 before the crop so i did that and got the video cleaner. however some other places said that for INTERLACED (i have a 720p source so im like 99.9999999999% sure that im not interlaced thanks to that nice "p" and the fact that i dont see a hint of combing anywhere) you should use softskip. in an attempt to mess around i replaced decimate with softskip and i noticed that the video was less jumpy. so now i ask, why would someone use decimate over softskip if softskip works just as well? whats the benefits/risks to using either?

btw im using mencoder on a freebsd box to do my encoding. im using x264 with the following options:
crf=22:psnr:8x8dct:4x4mv:mixed_refs:b_pyramid:frameref=10:weight_b:me=3:bframes=3:subq=6:brdo:bime:nofast_pskip

mencoder and x264 were compiled this morning (4-27-06) since i found another issue in my system that required me to rebuild mplayer/mencoder so i upgraded x264 at the same time.

[Prysme]

Could you please provide us with the complete mencoder command line in order to make a test ?
Tks.

[morph166955]

here ya go:

/usr/bin/time -ao x264-decimate.txt mencoder House.tp -ofps 30000/1001 -af volnorm=2:.40 -oac mp3lame -lameopts preset=standard -ovc x264 -x264encopts crf=22:psnr:8x8dct:4x4mv:mixed_refs:b_pyramid:frameref=10:weight_b:me=3:bframes=3:subq=6:brdo:bime:nofast_pskip -o H-264-720x406-30fps-decimate.avi -vf decimate=2:1000:1600:.001,crop=1280:704:0:10,scale=720:-2 2>&1 | tr "^M" "\\n" > x264run-decimate.txt 2>&1

/usr/bin/time -ao x264-softskip.txt mencoder House.tp -ofps 30000/1001 -af volnorm=2:.40 -oac mp3lame -lameopts preset=standard -ovc x264 -x264encopts crf=22:psnr:8x8dct:4x4mv:mixed_refs:b_pyramid:frameref=10:weight_b:me=3:bframes=3:subq=6:brdo:bime:nofast_pskip -o H-264-720x406-30fps-softskip.avi -vf softskip,crop=1280:704:0:10,scale=720:-2 2>&1 | tr "^M" "\\n" > x264run-softskip.txt 2>&1

also, heres some info on the decimate run (the softskip is still goin i re-ran em last night):
x264 [info]: slice I:953 Avg QP:21.15 size: 21559 PSNR Mean Y:45.48 U:46.82 V:47.72 Avg:45.95 Global:45.59
x264 [info]: slice P:44467 Avg QP:23.29 size: 6391 PSNR Mean Y:43.89 U:45.65 V:46.56 Avg:44.45 Global:43.86
x264 [info]: slice B:63150 Avg QP:24.93 size: 1590 PSNR Mean Y:43.33 U:45.32 V:46.45 Avg:43.96 Global:43.46
x264 [info]: mb I I16..4: 30.0% 49.4% 20.6%
x264 [info]: mb P I16..4: 7.3% 8.2% 1.8% P16..4: 42.4% 11.7% 4.5% 0.4% 0.2% skip:23.6%
x264 [info]: mb B I16..4: 0.3% 0.4% 0.1% B16..8: 26.4% 1.3% 2.3% direct: 1.3% skip:67.9%
x264 [info]: 8x8 transform intra:47.9% inter:67.5%
x264 [info]: ref P 69.5% 13.8% 7.1% 2.5% 1.9% 1.7% 1.4% 0.7% 0.6% 0.7%
x264 [info]: ref B 81.6% 9.3% 3.2% 1.7% 1.1% 1.0% 0.7% 0.5% 0.4% 0.5%
x264 [info]: PSNR Mean Y:43.581 U:45.473 V:46.507 Avg:44.176 Global:43.635 kb/s:894.72

soft skip info to come later

[morph166955]

so some more info...when i start to snip up the x264 video i just made with decimate i get errors saying it cant find a reference frame. when i use softskip i dont get any errors and its also clean. whats the deal?

btw, psnr info on softskip:
x264 [info]: mb I I16..4: 30.0% 49.6% 20.4%
x264 [info]: mb P I16..4: 6.8% 7.7% 1.6% P16..4: 43.6% 11.6% 4.5% 0.4% 0.2% skip:23.7%
x264 [info]: mb B I16..4: 0.2% 0.3% 0.1% B16..8: 23.6% 1.0% 1.8% direct: 1.1% skip:71.9%
x264 [info]: 8x8 transform intra:48.1% inter:68.4%
x264 [info]: ref P 69.5% 13.6% 7.2% 2.5% 2.0% 1.7% 1.5% 0.7% 0.7% 0.7%
x264 [info]: ref B 84.3% 8.2% 2.9% 1.3% 0.9% 0.7% 0.6% 0.4% 0.3% 0.3%
x264 [info]: PSNR
ean Y:43.791 U:45.534 V:46.643 Avg:44.359 Global:43.831 kb/s:795.79

[Zep]

720p is normally 60 FPS (well here in the states anyway) so you want to do a selecteven() on it. Now since this show is scripted it is 23.97 like most scripted shows. So you want to use decimate(5) next.

there will be no jumpiness at all but when in doubt just step through the show 1 frame at a time and look for dupes.

all you need really is


Selecteven()
Crop(16,16,-16,-16) #whatever works best of course
Decimate(5)
Lanczos4Resize(960,528)


and it will look awesome

good luck