[PR] avfilter/vf_xpsnr: avoid a zero block size on small frames (PR #23908)

PR #23908 opened by michaelni
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23908
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23908.patch

Fixes: division by zero
Fixes: SUcVEyk7r3Gc
Found-by: Kenan Alghythee <[email protected]>



>From 1daa28b33b5e68e35c496867e4b95da1de473e34 Mon Sep 17 00:00:00 2001
From: Kenan Alghythee <[email protected]>
Date: Sat, 11 Jul 2026 16:53:41 +0200
Subject: [PATCH] avfilter/vf_xpsnr: avoid a zero block size on small frames

Fixes: division by zero
Fixes: SUcVEyk7r3Gc
Found-by: Kenan Alghythee <[email protected]>
---
 libavfilter/vf_xpsnr.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavfilter/vf_xpsnr.c b/libavfilter/vf_xpsnr.c
index 34c875456e..89f4f279ba 100644
--- a/libavfilter/vf_xpsnr.c
+++ b/libavfilter/vf_xpsnr.c
@@ -273,7 +273,7 @@ static int get_wsse(AVFilterContext *ctx, int16_t **org, int16_t *org_m1,
     const uint32_t       w = s->plane_width [0]; /* luma image width in pixels */
     const uint32_t       h = s->plane_height[0];/* luma image height in pixels */
     const double         r = (double)(w * h) / (3840.0 * 2160.0); /* UHD ratio */
-    const uint32_t       b = FFMAX(0, 4 * (int32_t) (32.0 * sqrt(r) +
+    const uint32_t       b = FFMAX(1, 4 * (int32_t) (32.0 * sqrt(r) +
                                                      0.5)); /* block size, integer multiple of 4 for SIMD */
     const uint32_t   w_blk = (w + b - 1) / b; /* luma width in units of blocks */
     const double   avg_act = sqrt(16.0 * (double) (1 << (2 * s->depth - 9)) / sqrt(FFMAX(0.00001,
@@ -399,7 +399,7 @@ static int do_xpsnr(FFFrameSync *fs)
     XPSNRContext *const s = ctx->priv;
     const uint32_t      w = s->plane_width [0];  /* luma image width in pixels */
     const uint32_t      h = s->plane_height[0]; /* luma image height in pixels */
-    const uint32_t      b = FFMAX(0, 4 * (int32_t) (32.0 * sqrt((double) (w * h) / (3840.0 * 2160.0)) + 0.5)); /* block size */
+    const uint32_t      b = FFMAX(1, 4 * (int32_t) (32.0 * sqrt((double) (w * h) / (3840.0 * 2160.0)) + 0.5)); /* block size */
     const uint32_t  w_blk = (w + b - 1) / b;  /* luma width in units of blocks */
     const uint32_t  h_blk = (h + b - 1) / b; /* luma height in units of blocks */
     AVFrame *master, *ref = NULL;
-- 
2.52.0

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