[FFmpeg-cvslog] swscale/input: Use more unsigned intermediates

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Tue Nov 15 23:10:02 2022 +0100| [a604063ede5a64123d9e44f00fd951d6c6019eb5] | committer: Michael Niedermayer

swscale/input: Use more unsigned intermediates

Same principle as previous commit, with sufficiently huge rgb2yuv table
values this produces wrong results and undefined behavior.
The unsigned produces the same incorrect results. That is probably
ok as these cases with huge values seem not to occur in any real
use case.

Fixes: signed integer overflow
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit ba209e3d5142fd31bb6c3e05c5b183118a278afc)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a604063ede5a64123d9e44f00fd951d6c6019eb5
---

 libswscale/input.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/libswscale/input.c b/libswscale/input.c
index 159f70307d..bc0eec65b8 100644
--- a/libswscale/input.c
+++ b/libswscale/input.c
@@ -84,9 +84,9 @@ rgb64ToUV_half_c_template(uint16_t *dstU, uint16_t *dstV,
     int32_t rv = rgb2yuv[RV_IDX], gv = rgb2yuv[GV_IDX], bv = rgb2yuv[BV_IDX];
     av_assert1(src1==src2);
     for (i = 0; i < width; i++) {
-        int r_b = (input_pixel(&src1[8 * i + 0]) + input_pixel(&src1[8 * i + 4]) + 1) >> 1;
-        int   g = (input_pixel(&src1[8 * i + 1]) + input_pixel(&src1[8 * i + 5]) + 1) >> 1;
-        int b_r = (input_pixel(&src1[8 * i + 2]) + input_pixel(&src1[8 * i + 6]) + 1) >> 1;
+        unsigned r_b = (input_pixel(&src1[8 * i + 0]) + input_pixel(&src1[8 * i + 4]) + 1) >> 1;
+        unsigned   g = (input_pixel(&src1[8 * i + 1]) + input_pixel(&src1[8 * i + 5]) + 1) >> 1;
+        unsigned b_r = (input_pixel(&src1[8 * i + 2]) + input_pixel(&src1[8 * i + 6]) + 1) >> 1;
 
         dstU[i]= (ru*r + gu*g + bu*b + (0x10001<<(RGB2YUV_SHIFT-1))) >> RGB2YUV_SHIFT;
         dstV[i]= (rv*r + gv*g + bv*b + (0x10001<<(RGB2YUV_SHIFT-1))) >> RGB2YUV_SHIFT;
@@ -156,9 +156,9 @@ static av_always_inline void rgb48ToUV_c_template(uint16_t *dstU,
     int32_t rv = rgb2yuv[RV_IDX], gv = rgb2yuv[GV_IDX], bv = rgb2yuv[BV_IDX];
     av_assert1(src1 == src2);
     for (i = 0; i < width; i++) {
-        int r_b = input_pixel(&src1[i * 3 + 0]);
-        int g   = input_pixel(&src1[i * 3 + 1]);
-        int b_r = input_pixel(&src1[i * 3 + 2]);
+        unsigned r_b = input_pixel(&src1[i * 3 + 0]);
+        unsigned g   = input_pixel(&src1[i * 3 + 1]);
+        unsigned b_r = input_pixel(&src1[i * 3 + 2]);
 
         dstU[i] = (ru*r + gu*g + bu*b + (0x10001 << (RGB2YUV_SHIFT - 1))) >> RGB2YUV_SHIFT;
         dstV[i] = (rv*r + gv*g + bv*b + (0x10001 << (RGB2YUV_SHIFT - 1))) >> RGB2YUV_SHIFT;
@@ -178,12 +178,12 @@ static av_always_inline void rgb48ToUV_half_c_template(uint16_t *dstU,
     int32_t rv = rgb2yuv[RV_IDX], gv = rgb2yuv[GV_IDX], bv = rgb2yuv[BV_IDX];
     av_assert1(src1 == src2);
     for (i = 0; i < width; i++) {
-        int r_b = (input_pixel(&src1[6 * i + 0]) +
-                   input_pixel(&src1[6 * i + 3]) + 1) >> 1;
-        int g   = (input_pixel(&src1[6 * i + 1]) +
-                   input_pixel(&src1[6 * i + 4]) + 1) >> 1;
-        int b_r = (input_pixel(&src1[6 * i + 2]) +
-                   input_pixel(&src1[6 * i + 5]) + 1) >> 1;
+        unsigned r_b = (input_pixel(&src1[6 * i + 0]) +
+                        input_pixel(&src1[6 * i + 3]) + 1) >> 1;
+        unsigned g   = (input_pixel(&src1[6 * i + 1]) +
+                        input_pixel(&src1[6 * i + 4]) + 1) >> 1;
+        unsigned b_r = (input_pixel(&src1[6 * i + 2]) +
+                        input_pixel(&src1[6 * i + 5]) + 1) >> 1;
 
         dstU[i] = (ru*r + gu*g + bu*b + (0x10001 << (RGB2YUV_SHIFT - 1))) >> RGB2YUV_SHIFT;
         dstV[i] = (rv*r + gv*g + bv*b + (0x10001 << (RGB2YUV_SHIFT - 1))) >> RGB2YUV_SHIFT;