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Old 6th January 2011, 08:47   #1  |  Link
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mencoder resizing using -sws flag

Hy there!

I want to downscale a FullHD stream to pal-dvd size 720x576 using the -sws flag.
(walking on a Ubuntu 10.04 server)

My commandline looks like this:
mencoder video-delay3,6.mpg -channels 6 -oac copy -ovc lavc -of mpeg -mpegopts format=dvd:tsaf
-vf scale=720:437,expand=720:576,harddup -sws 9 -srate 48000 -af lavcresample=48000
-lavcopts threads=256:vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=9799:
dc=10:aspect=16/9:vstrict=0:vpsize=500:vfdct=0:idct=0 -ofps 25 -o movie.mpg

So, this is using lanczos for resizing. (-sws 9)

How do I adjust the strength of the filter?

man (manual of) mencoder tells me:
scale [= w: h [: ilaced [: chr_drop [: par [: par2 [: presize [: noup [: arnd ]]]]]]]]
  • Scales the image with the software (slow) and performs a color space conversion between YUV and RGB through (see the -sws).

<par> [: <par2>] (also see -sws)
Set some scaling parameters depending on the scaling, which was selected with-sws.
  • -sws 2 (bicubic): B (blurring) and C (Gain)
  • 0.00:0.60 Standard
  • 0.00:0.75 "precise bicubic" VirtualDub
  • 0.00:0.50 Catmull-Rom spline
  • 0.33:0.33 Mitchell-Netravali spline
  • 1.00:0.00 cubic B-spline
  • -sws 7 (gaussian): sharpness (0 (soft) - 100 (sharp))
  • -sws 9 (Lanczos): filter length (1-10)

But how do I have to use this in command-line?

my regards

Last edited by Nonoman; 7th January 2011 at 09:05. Reason: Edited text
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Old 15th January 2011, 10:44   #2  |  Link
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Posts: 28
can you tell me what's the mencoder websit?
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Old 15th January 2011, 10:44   #3  |  Link
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Join Date: Feb 2010
Posts: 28
do you have mencoder's options!
i can't find it
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Old 4th July 2011, 21:42   #4  |  Link
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Posts: 35
Ok I figured it out for mplayer:
-sws 9 -vf scale=1280:0:0:0:10# 10 is the filter length...I think so anyway, though it doesn't complain if I set it to 11.

Also does anybody know if it accepts sharpen parameters, like -ssf ls=75.0 -ssf cs=75.0 ?

if it works, it will display "Lanczos" in the output after a few lines.
rogerdpack is offline   Reply With Quote

command-line, lanczos, mencoder, resize, ubuntu

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