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 <michael@niedermayer.cc>
(cherry picked from commit c1f9734f977f59bc0034096afbe8e43e40d93a5d)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
Marios Titas authored on 2016/04/03 03:11:44Showing 1 changed files
| ... | ... |
@@ -240,7 +240,7 @@ static av_cold int movie_common_init(AVFilterContext *ctx) |
| 240 | 240 |
timestamp = movie->seek_point; |
| 241 | 241 |
// add the stream start time, should it exist |
| 242 | 242 |
if (movie->format_ctx->start_time != AV_NOPTS_VALUE) {
|
| 243 |
- if (timestamp > INT64_MAX - movie->format_ctx->start_time) {
|
|
| 243 |
+ if (timestamp > 0 && movie->format_ctx->start_time > INT64_MAX - timestamp) {
|
|
| 244 | 244 |
av_log(ctx, AV_LOG_ERROR, |
| 245 | 245 |
"%s: seek value overflow with start_time:%"PRId64" seek_point:%"PRId64"\n", |
| 246 | 246 |
movie->file_name, movie->format_ctx->start_time, movie->seek_point); |