From fc016fd665903b61bcf37c5d23897fe951f5d8e6 Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Sun, 4 Dec 2022 13:19:50 +0100
Subject: [PATCH] avfilter/vf_exposure: ensure that scale is always > 0

---
 libavfilter/vf_exposure.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/libavfilter/vf_exposure.c b/libavfilter/vf_exposure.c
index 108fba7930..bbe951967b 100644
--- a/libavfilter/vf_exposure.c
+++ b/libavfilter/vf_exposure.c
@@ -67,8 +67,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
 {
     AVFilterContext *ctx = inlink->dst;
     ExposureContext *s = ctx->priv;
+    float diff = fabsf(exp2f(-s->exposure) - s->black);
 
-    s->scale = 1.f / (exp2f(-s->exposure) - s->black);
+    diff = diff > 0.f ? diff : 1.f / 1024.f;
+    s->scale = 1.f / diff;
     ff_filter_execute(ctx, s->do_slice, frame, NULL,
                       FFMIN(frame->height, ff_filter_get_nb_threads(ctx)));