If ff_subtitles_queue_insert() were given a NULL buffer with 0 length, it would still attempt to grow the packet or memcpy depending on if merge option is enabled.
In this commit, allow passing a NULL buffer with 0 length without attempting to do such operations. This way, if a subtitle demuxer happens to pass an empty cue or wants to use av_get_packet() to read bytes, there are no unnecessary operations on the packet after it is allocated. Signed-off-by: Marth64 <mart...@proxyid.net> --- libavformat/subtitles.c | 23 +++++++++++++++-------- libavformat/subtitles.h | 2 +- 2 files changed, 16 insertions(+), 9 deletions(-) diff --git a/libavformat/subtitles.c b/libavformat/subtitles.c index 3413763c7b..1c9b229f5b 100644 --- a/libavformat/subtitles.c +++ b/libavformat/subtitles.c @@ -21,6 +21,7 @@ #include "avformat.h" #include "subtitles.h" #include "avio_internal.h" +#include "libavutil/avassert.h" #include "libavutil/avstring.h" void ff_text_init_avio(void *s, FFTextReader *r, AVIOContext *pb) @@ -111,15 +112,19 @@ AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, { AVPacket **subs, *sub; + av_assert1(event || len == 0); + if (merge && q->nb_subs > 0) { /* merge with previous event */ int old_len; sub = q->subs[q->nb_subs - 1]; old_len = sub->size; - if (av_grow_packet(sub, len) < 0) - return NULL; - memcpy(sub->data + old_len, event, len); + if (event) { + if (av_grow_packet(sub, len) < 0) + return NULL; + memcpy(sub->data + old_len, event, len); + } } else { /* new event */ @@ -133,14 +138,16 @@ AVPacket *ff_subtitles_queue_insert(FFDemuxSubtitlesQueue *q, sub = av_packet_alloc(); if (!sub) return NULL; - if (av_new_packet(sub, len) < 0) { - av_packet_free(&sub); - return NULL; + if (event) { + if (av_new_packet(sub, len) < 0) { + av_packet_free(&sub); + return NULL; + } + memcpy(sub->data, event, len); } - subs[q->nb_subs++] = sub; sub->flags |= AV_PKT_FLAG_KEY; sub->pts = sub->dts = 0; - memcpy(sub->data, event, len); + subs[q->nb_subs++] = sub; } return sub; } diff --git a/libavformat/subtitles.h b/libavformat/subtitles.h index 88665663c5..ad6b96ca6a 100644 --- a/libavformat/subtitles.h +++ b/libavformat/subtitles.h @@ -112,7 +112,7 @@ typedef struct { /** * Insert a new subtitle event. * - * @param event the subtitle line, may not be zero terminated + * @param event the subtitle line (not zero terminated) or NULL on not yet available event * @param len the length of the event (in strlen() sense, so without '\0') * @param merge set to 1 if the current event should be concatenated with the * previous one instead of adding a new entry, 0 otherwise -- 2.34.1 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".