[MPlayer-users] BUG: MMX code in spp filter induces ringing

[jbcrowso at ncsu.edu]

When playing with the spp filter recently, I have found that the MMX code
induces ringing.  It does not do so on all sources, only those with sharp
edges, like anime with hard subtitles.  The ringing occurs regardless of
forced qp (even when it's set to 1), in both (hard and soft thresholding)
modes.  It does not occur when using the C version of either mode.

At http://www4.ncsu.edu/~jbcrowso/test.png is a file which contains sharp
edges for testing.  To reproduce this bug, download it and run "mplayer
mf://test.png -vf format=yv12,spp=3:1:0 -vo png" and examine the output. 
Due to the way the spp filter processes parameters, passing an invalid
parameter for the third (mode) option will cause it to stay with the
default of the C hard thresholding code, so you can verify that the C
version operates correctly with "mplayer mf://test.png -vf
format=yv12,spp=3:1:2 -vo png".