[FFmpeg-devel] [PATCH 5/5] avcodec/utvideodec: Factor multiply out of inner loop

Michael Niedermayer michael at niedermayer.cc
Tue Jun 27 22:47:35 EEST 2017


0.5% faster loop

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/utvideodec.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/utvideodec.c b/libavcodec/utvideodec.c
index 788f4475b9..a20e28320c 100644
--- a/libavcodec/utvideodec.c
+++ b/libavcodec/utvideodec.c
@@ -196,7 +196,8 @@ static int decode_plane10(UtvideoContext *c, int plane_no,
 
         prev = 0x200;
         for (j = sstart; j < send; j++) {
-            for (i = 0; i < width * step; i += step) {
+            int ws = width * step;
+            for (i = 0; i < ws; i += step) {
                 pix = get_vlc2(&gb, vlc.table, VLC_BITS, 3);
                 if (pix < 0) {
                     av_log(c->avctx, AV_LOG_ERROR, "Decoding error\n");
@@ -300,7 +301,8 @@ static int decode_plane(UtvideoContext *c, int plane_no,
 
         prev = 0x80;
         for (j = sstart; j < send; j++) {
-            for (i = 0; i < width * step; i += step) {
+            int ws = width * step;
+            for (i = 0; i < ws; i += step) {
                 pix = get_vlc2(&gb, vlc.table, VLC_BITS, 3);
                 if (pix < 0) {
                     av_log(c->avctx, AV_LOG_ERROR, "Decoding error\n");
-- 
2.13.0



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