[FFmpeg-devel] [PATCH] avfilter/fade: don't allow nb_frames == 0

[Gyan]

Fixes crash when user inputs a sub-unit fractional number for nb_frames.

Gyan
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From b3e463c6514eabb1081a22e32dce33d62f5278ce Mon Sep 17 00:00:00 2001
From: Gyan Doshi <ffmpeg at gyani.pro>
Date: Mon, 29 Jul 2019 10:53:12 +0530
Subject: [PATCH] avfilter/fade: don't allow nb_frames == 0

In filter init, there's a division by nb_frames but value isn't checked.
---
 libavfilter/vf_fade.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavfilter/vf_fade.c b/libavfilter/vf_fade.c
index 17eca109b6..bec765a09e 100644
--- a/libavfilter/vf_fade.c
+++ b/libavfilter/vf_fade.c
@@ -381,9 +381,9 @@ static const AVOption fade_options[] = {
     { "s",           "Number of the first frame to which to apply the effect.",
                                                     OFFSET(start_frame), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, FLAGS },
     { "nb_frames",   "Number of frames to which the effect should be applied.",
-                                                    OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 0, INT_MAX, FLAGS },
+                                                    OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 1, INT_MAX, FLAGS },
     { "n",           "Number of frames to which the effect should be applied.",
-                                                    OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 0, INT_MAX, FLAGS },
+                                                    OFFSET(nb_frames),   AV_OPT_TYPE_INT, { .i64 = 25 }, 1, INT_MAX, FLAGS },
     { "alpha",       "fade alpha if it is available on the input", OFFSET(alpha),       AV_OPT_TYPE_BOOL, {.i64 = 0    }, 0,       1, FLAGS },
     { "start_time",  "Number of seconds of the beginning of the effect.",
                                                     OFFSET(start_time),  AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT64_MAX, FLAGS },
-- 
2.22.0