[FFmpeg-devel] [PATCH 4/6] avcodec/hnm4video: Optimize postprocess_current_frame()

[Michael Niedermayer]

On Sat, Aug 03, 2019 at 04:07:22PM +0200, Tomas Härdin wrote:
> lör 2019-08-03 klockan 01:49 +0200 skrev Michael Niedermayer:
> > -    uint32_t x, y, src_x, src_y;
> > +    uint32_t x, y, src_y;
> > +    int width = hnm->width;
> >  
> >      for (y = 0; y < hnm->height; y++) {
> > +        uint8_t *dst = hnm->processed + y * width;
> > +        const uint8_t *src = hnm->current;
> >          src_y = y - (y % 2);
> > -        src_x = src_y * hnm->width + (y % 2);
> > -        for (x = 0; x < hnm->width; x++) {
> > -            hnm->processed[(y * hnm->width) + x] = hnm-
> > >current[src_x];
> > -            src_x += 2;
> > +        src += src_y * width + (y % 2);
> > +        for (x = 0; x < width; x++) {
> > +            dst[x] = *src;
> > +            src += 2;
> 
> Looks OK. Maybe telling the compiler that src and dst don't alias would
> be worthwhile?

i can add restrict keywords if you want:
?

diff --git a/libavcodec/hnm4video.c b/libavcodec/hnm4video.c
index 68d0baef6d..1c2501afab 100644
--- a/libavcodec/hnm4video.c
+++ b/libavcodec/hnm4video.c
@@ -121,8 +121,8 @@ static void postprocess_current_frame(AVCodecContext *avctx)
     int width = hnm->width;
 
     for (y = 0; y < hnm->height; y++) {
-        uint8_t *dst = hnm->processed + y * width;
-        const uint8_t *src = hnm->current;
+        uint8_t * restrict dst = hnm->processed + y * width;
+        const uint8_t * restrict src = hnm->current;
         src_y = y - (y % 2);
         src += src_y * width + (y % 2);
         for (x = 0; x < width; x++) {


[...]
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Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you fake or manipulate statistics in a paper in physics you will never
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