[FFmpeg-cvslog] avfilter/vf_mpdecimate: add comment about 8x8 SAD

[Peter Cordes]

ffmpeg | branch: master | Peter Cordes <peter at cordes.ca> | Wed Mar  4 03:35:36 2015 -0400| [3ad3529b567e04a812c0ff103855ecba3efff900] | committer: Michael Niedermayer

avfilter/vf_mpdecimate: add comment about 8x8 SAD

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=3ad3529b567e04a812c0ff103855ecba3efff900
---

 libavfilter/vf_mpdecimate.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavfilter/vf_mpdecimate.c b/libavfilter/vf_mpdecimate.c
index cb3e69f..7cc3254 100644
--- a/libavfilter/vf_mpdecimate.c
+++ b/libavfilter/vf_mpdecimate.c
@@ -120,6 +120,11 @@ static int decimate_frame(AVFilterContext *ctx,
         return 0;
 
     for (plane = 0; ref->data[plane] && ref->linesize[plane]; plane++) {
+        /* use 8x8 SAD even on subsampled planes.  The blocks won't match up with
+         * luma blocks, but hopefully nobody is depending on this to catch
+         * localized chroma changes that wouldn't exceed the thresholds when
+         * diluted by using what's effectively a larger block size.
+         */
         int vsub = plane == 1 || plane == 2 ? decimate->vsub : 0;
         int hsub = plane == 1 || plane == 2 ? decimate->hsub : 0;
         if (diff_planes(ctx,