Commit Graph

3 Commits

Author SHA1 Message Date
Thilo Borgmann c42d513ede lavf/mov: Change default to prefer TFDT time and allow for fallback to SIDX or TFDT 2021-11-05 16:22:04 +01:00
Jonas Licht 59ad504696 libavformat/mov.c: use calculated dts offset when seeking in streams
Subtract the calculated dts offset from the requested timestamp before
seeking. This fixes an error "Error while filtering: Operation not
permitted" observed with a short file which contains only one key frame
and starts with negative timestamps.

Then, av_index_search_timestamp() returns a valid negative timestamp,
but mov_seek_stream bails out with AVERROR_INVALIDDATA.

Fixes ticket #6139.

Signed-off-by: Jonas Licht <jonas.licht@fem.tu-ilmenau.de>
Signed-off-by: Peter Große <pegro@friiks.de>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2017-10-30 01:09:40 +01:00
Dale Curtis 37e8edc9f5 avformat/mov: Fix trampling of ctts during seeks when sidx support is enabled.
When sidx box support is enabled, the code will skip reading all
trun boxes (each containing ctts entries for samples inthat box).

If seeks are attempted before all ctts values are known, the old
code would dump ctts entries into the wrong location. These are
then used to compute pts values which leads to out of order and
incorrectly timestamped packets.

This patch fixes ctts processing by always using the index returned
by av_add_index_entry() as the ctts_data index. When the index gains
new entries old values are reshuffled as appropriate.

This approach makes sense since the mov demuxer is already relying
on the mapping of AVIndex entries to samples for correct demuxing.

As a result of this all ctts entries are now 1-count. A followup
change will be submitted to remove support for > 1 count entries
which will simplify seeking.

Notes for future improvement:
Probably there are other boxes (stts, stsc, etc) that are impacted
by this issue... this patch only attempts to fix ctts since it
completely breaks packet timestamping.

This patch continues using an array for the ctts data, which is not
the most ideal given the rearrangement that needs to happen (via
memmove as new entries are read in). Ideally AVIndex and the ctts
data would be set-type structures so addition is always worst case
O(lg(n)) instead of the O(n^2) that exists now; this slowdown is
noticeable during seeks.

Signed-off-by: Dale Curtis <dalecurtis@chromium.org>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
2017-08-24 11:02:22 +02:00