[FFmpeg-devel] [PATCH] avfilter/vf_scale_d3d12: fix integer overflow in input framerate calculation (PR #21130)

[Timo Rothenpieler via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #21130 opened by Timo Rothenpieler (BtbN)
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21130
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/21130.patch

Also removes pointless intermediate variables that caused
the overflow and truncation to happen in the first place.

Fixes #YWH-PGM40646-1


>From 338889c0d9794782ea1b247bce934df50e5ade8c Mon Sep 17 00:00:00 2001
From: Timo Rothenpieler <timo@rothenpieler.org>
Date: Mon, 8 Dec 2025 14:18:36 +0100
Subject: [PATCH] avfilter/vf_scale_d3d12: fix integer overflow in input
 framerate calculation

Also removes pointless intermediate variables that caused
the overflow and truncation to happen in the first place.

Fixes #YWH-PGM40646-1
---
 libavfilter/vf_scale_d3d12.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/libavfilter/vf_scale_d3d12.c b/libavfilter/vf_scale_d3d12.c
index 6950feb32b..8066bd0725 100644
--- a/libavfilter/vf_scale_d3d12.c
+++ b/libavfilter/vf_scale_d3d12.c
@@ -155,8 +155,6 @@ static DXGI_COLOR_SPACE_TYPE get_dxgi_colorspace(enum AVColorSpace colorspace, e
 
 static AVRational get_input_framerate(AVFilterContext *ctx, AVFilterLink *inlink, AVFrame *in)
 {
-    int64_t duration_scaled;
-    int64_t time_base_den;
     AVRational framerate = {0, 0};
 
     if (in->duration > 0 && inlink->time_base.num > 0 && inlink->time_base.den > 0) {
@@ -164,13 +162,9 @@ static AVRational get_input_framerate(AVFilterContext *ctx, AVFilterLink *inlink
         * Calculate framerate from frame duration and timebase
         * framerate = 1 / (duration * timebase)
         */
-        duration_scaled = in->duration * inlink->time_base.num;
-        time_base_den = inlink->time_base.den;
-        framerate.num = time_base_den;
-        framerate.den = duration_scaled;
-        /* Reduce the fraction */
         av_reduce(&framerate.num, &framerate.den,
-                 framerate.num, framerate.den, INT_MAX);
+                  inlink->time_base.den, in->duration * inlink->time_base.num,
+                  INT_MAX);
     } else if (inlink->time_base.num > 0 && inlink->time_base.den > 0) {
         /* Estimate from timebase (inverse of timebase is often the framerate) */
         framerate.num = inlink->time_base.den;
-- 
2.49.1

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