The MOVFragmentIndexItems of a MOVFragmentIndex are ordered
by increasing moof_offset; yet get_frag_stream_info_from_pkt()
searched the array of index items linearly for the item
with moof_offset <= pos < moof_offset of next index (if existing).
This commit changes this: First, it is checked, whether
the current item or the next item are the desired items;
it this fails, a array is searched via binary search.
Fixes ticket #9941.
Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com>
---
The earlier code reused current in case pkt->pos is before
the first moof_offset. I kept this behaviour, although I don't know
whether this can actually happen.
libavformat/mov.c | 44 +++++++++++++++++++++++++++++---------------
1 file changed, 29 insertions(+), 15 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 1f436e21d6..79331638b0 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -7192,26 +7192,40 @@ static int cenc_decrypt(MOVContext *c, MOVStreamContext
*sc, AVEncryptionInfo *s
static MOVFragmentStreamInfo *get_frag_stream_info_from_pkt(MOVFragmentIndex
*frag_index, AVPacket *pkt, int id)
{
int current = frag_index->current;
+ int next = -1;
if (!frag_index->nb_items)
return NULL;
// Check frag_index->current is the right one for pkt. It can out of sync.
- if (current >= 0 && current < frag_index->nb_items) {
- if (frag_index->item[current].moof_offset < pkt->pos &&
- (current + 1 == frag_index->nb_items ||
- frag_index->item[current + 1].moof_offset > pkt->pos))
- return get_frag_stream_info(frag_index, current, id);
- }
-
-
- for (int i = 0; i < frag_index->nb_items; i++) {
- if (frag_index->item[i].moof_offset > pkt->pos)
- break;
- current = i;
- }
- frag_index->current = current;
- return get_frag_stream_info(frag_index, current, id);
+ if (current >= 0 && current < frag_index->nb_items &&
+ frag_index->item[current].moof_offset <= pkt->pos) {
+ if (current + 1U == frag_index->nb_items ||
+ frag_index->item[current + 1].moof_offset > pkt->pos) {
+ next = current;
+ } else if (current + 2U == frag_index->nb_items ||
+ frag_index->item[current + 2].moof_offset > pkt->pos)
+ next = current + 1;
+ }
+
+ if (next < 0) {
+ if (pkt->pos < frag_index->item[0].moof_offset) {
+ /* Can this happen? Does this make sense? */
+ next = current;
+ } else {
+ next = search_frag_moof_offset(frag_index, pkt->pos);
+ /* If there is no exact match for pkt->pos, then
+ * search_frag_moof_offset() returns the index of
+ * the first item with moof_offset > pkt->pos
+ * (or frag_index->nb_items if no such item exists). */
+ if (next == frag_index->nb_items)
+ next = frag_index->nb_items - 1;
+ else if (frag_index->item[next].moof_offset > pkt->pos)
+ next--;
+ }
+ }
+ frag_index->current = next;
+ return get_frag_stream_info(frag_index, next, id);
}
static int cenc_filter(MOVContext *mov, AVStream* st, MOVStreamContext *sc,
AVPacket *pkt, int current_index)
--
2.34.1
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