Commit dace243da8 for ffmpeg
commit dace243da83ff60c8c21026f99d8239d0458fc47
Author: Greg Falcon <gfalcon@google.com>
Date: Tue Oct 27 12:58:57 2026 -0400
swscale/aarch64: fix signed load in yuv2planeX_10
The horizontal scaler intermediate buffer holds signed 16-bit samples
that can be negative when scaling with filters that have negative lobes
(such as bicubic). The 16-pixel and 8-pixel NEON vector loops in
ff_yuv2planeX_10_neon treat src as signed int16_t via smlal, but the
scalar tail loop for remaining (dstW % 8) pixels used unsigned ldrh
before sxtw, interpreting negative intermediate values as large positive
values around 65536 and saturating output pixels.
Use ldrsh instead of ldrh so negative intermediate samples are properly
sign-extended in the scalar tail loop.
Signed-off-by: Marvin Scholz <epirat07@gmail.com>
diff --git a/libswscale/aarch64/output.S b/libswscale/aarch64/output.S
index a650d72f54..2e559ba1e5 100644
--- a/libswscale/aarch64/output.S
+++ b/libswscale/aarch64/output.S
@@ -165,7 +165,7 @@ function ff_yuv2planeX_10_neon, export=1
ldr x14, [x12], #8 // Load src pointer
ldrsh w15, [x13], #2 // Load filter coefficient
add x14, x14, x7, lsl #1 // Add pixel offset
- ldrh w16, [x14]
+ ldrsh w16, [x14]
sxtw x16, w16
sxtw x15, w15