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Fix UB issue calculating the frame duration for images with FFMPEG

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AVFormatContext::duration was used without checking it was set,
calculations for the frame-rate cast -INT64_MAX to a double,
scaled it then cast to an integer - overflowing.
On my system the result was a negative number so the duration was never
usable in practice.

Add an explicit check for this so the duration is left at zero instead.
This commit is contained in:
Campbell Barton
2023-10-13 10:48:25 +11:00
parent df108825c0
commit aebb32748e
1 changed files with 14 additions and 4 deletions
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18
source/blender/imbuf/intern/anim_movie.cc
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@@ -558,10 +558,20 @@ static int startffmpeg(anim *anim)
}
}
}
/* Fall back to manually estimating the video stream duration.
* This is because the video stream duration can be shorter than the pFormatCtx->duration.
*/
if (anim->duration_in_frames == 0) {
if (anim->duration_in_frames != 0) {
/* Pass (already valid). */
}
else if (pFormatCtx->duration == AV_NOPTS_VALUE) {
/* The duration has not been set, happens for single JPEG2000 images.
* NOTE: Leave the duration zeroed, although it could set to 1 so the file is recognized
* as a movie with 1 frame, leave as-is since image loading code-paths are preferred
* in this case. */
}
else {
/* Fall back to manually estimating the video stream duration.
* This is because the video stream duration can be shorter than the `pFormatCtx->duration`. */
BLI_assert(anim->duration_in_frames == 0);
double stream_dur;
if (video_stream->duration != AV_NOPTS_VALUE) {