ffmpeg | branch: master | Michael Niedermayer <[email protected]> | Wed Jan 6 23:24:49 2021 +0100| [a899d6ca101d0ed735e13dc4c57b0b8fc0465d37] | committer: Michael Niedermayer
avformat: Change avpriv_new_chapter() from O(n) to (1) in the common case Fixes: timeout (slow -> 300ms) Fixes: 28876/clusterfuzz-testcase-minimized-ffmpeg_dem_MOV_fuzzer-5664824587583488 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <[email protected]> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=a899d6ca101d0ed735e13dc4c57b0b8fc0465d37 --- libavformat/internal.h | 5 +++++ libavformat/utils.c | 11 ++++++++--- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/libavformat/internal.h b/libavformat/internal.h index 49e82bfbca..f45b1cd6b4 100644 --- a/libavformat/internal.h +++ b/libavformat/internal.h @@ -142,6 +142,11 @@ struct AVFormatInternal { * Prefer the codec framerate for avg_frame_rate computation. */ int prefer_codec_framerate; + + /** + * Set if chapter ids are strictly monotonic. + */ + int chapter_ids_monotonic; }; struct AVStreamInternal { diff --git a/libavformat/utils.c b/libavformat/utils.c index 1ec71691e5..9dab4fc96f 100644 --- a/libavformat/utils.c +++ b/libavformat/utils.c @@ -4614,9 +4614,14 @@ AVChapter *avpriv_new_chapter(AVFormatContext *s, int id, AVRational time_base, return NULL; } - for (i = 0; i < s->nb_chapters; i++) - if (s->chapters[i]->id == id) - chapter = s->chapters[i]; + if (!s->nb_chapters) { + s->internal->chapter_ids_monotonic = 1; + } else if (!s->internal->chapter_ids_monotonic || s->chapters[s->nb_chapters-1]->id >= id) { + s->internal->chapter_ids_monotonic = 0; + for (i = 0; i < s->nb_chapters; i++) + if (s->chapters[i]->id == id) + chapter = s->chapters[i]; + } if (!chapter) { chapter = av_mallocz(sizeof(AVChapter)); _______________________________________________ ffmpeg-cvslog mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
