[FFmpeg-cvslog] avcodec/h261dec: Simplify decoding motion vectors
Andreas Rheinhardt
git at videolan.org
Thu Jun 20 20:01:16 EEST 2024
ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinhardt at outlook.com> | Thu Jun 13 15:45:19 2024 +0200| [9933dfe103166c43569a3b5bd4649b2e7fcefa0a] | committer: Andreas Rheinhardt
avcodec/h261dec: Simplify decoding motion vectors
Don't use a LUT to negate followed by a conditional ordinary
negation immediately thereafter. Instead fold the two.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9933dfe103166c43569a3b5bd4649b2e7fcefa0a
---
libavcodec/h261dec.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/libavcodec/h261dec.c b/libavcodec/h261dec.c
index 6df8588bb6..852de8d535 100644
--- a/libavcodec/h261dec.c
+++ b/libavcodec/h261dec.c
@@ -208,10 +208,6 @@ static int h261_decode_mb_skipped(H261DecContext *h, int mba1, int mba2)
return 0;
}
-static const int mvmap[17] = {
- 0, -1, -2, -3, -4, -5, -6, -7, -8, -9, -10, -11, -12, -13, -14, -15, -16
-};
-
static int decode_mv_component(GetBitContext *gb, int v)
{
int mv_diff = get_vlc2(gb, h261_mv_vlc, H261_MV_VLC_BITS, 2);
@@ -220,9 +216,7 @@ static int decode_mv_component(GetBitContext *gb, int v)
if (mv_diff < 0)
return v;
- mv_diff = mvmap[mv_diff];
-
- if (mv_diff && !get_bits1(gb))
+ if (mv_diff && get_bits1(gb))
mv_diff = -mv_diff;
v += mv_diff;
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