From 3d9f1c0dbbcba0164ec5f0bd3497c481afc43062 Mon Sep 17 00:00:00 2001 From: Marios Titas Date: Sat, 2 Apr 2016 21:11:44 +0300 Subject: [PATCH] avfilter/src_movie: fix how we check for overflows with seek_point Currently, if the movie source filter is used and a seek_point is specified on a file that has a negative start time, ffmpeg will fail. An easy way to reproduce this is as follows: $ ffmpeg -vsync passthrough -filter_complex 'color=d=10,setpts=PTS-1/TB' test.mp4 $ ffmpeg -filter_complex 'movie=filename=test.mp4:seek_point=2' -f null - The problem is caused by checking for int64_t overflow the wrong way. In general, to check whether a + b overflows, it is not enough to do: a > INT64_MAX - b because b might be negative; the correct way is: b > 0 && > a > INT64_MAX - b Signed-off-by: Michael Niedermayer (cherry picked from commit c1f9734f977f59bc0034096afbe8e43e40d93a5d) Signed-off-by: Michael Niedermayer --- libavfilter/src_movie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavfilter/src_movie.c b/libavfilter/src_movie.c index 908c03e1d3..6df52f75cc 100644 --- a/libavfilter/src_movie.c +++ b/libavfilter/src_movie.c @@ -240,7 +240,7 @@ static av_cold int movie_common_init(AVFilterContext *ctx) timestamp = movie->seek_point; // add the stream start time, should it exist if (movie->format_ctx->start_time != AV_NOPTS_VALUE) { - if (timestamp > INT64_MAX - movie->format_ctx->start_time) { + if (timestamp > 0 && movie->format_ctx->start_time > INT64_MAX - timestamp) { av_log(ctx, AV_LOG_ERROR, "%s: seek value overflow with start_time:%"PRId64" seek_point:%"PRId64"\n", movie->file_name, movie->format_ctx->start_time, movie->seek_point);