Bug 407082

When trying to split a track, then overlap the 2 parts and add a wipe effect between them, if I want to play and see the transition then Kdenlive crashes.

I'm using another project, inserted into the current project (I use the first project to "stitch" together the videos, and then import it into the second project in order to have it act as one single video). Besides the fact that it is imported with a wrong duration (about 40% longer than in reality - with black at the end), after correcting the duration it often crashes when splitting the track.

STEPS TO REPRODUCE
1. Create a new project and import an existing Kdenlive project (same framerate) into this project. Insert the project into the timeline and crop the last part of the track (the extra black part - another reported bug).
2. Split the track (right click - Split at playhead) twice, delete the part between the 2 split points.
3. Move the last part to overlap the first and insert a wipe effect between the 2 track parts. 
4. Move the playhead before the split/overlap zone and try to play the project, in order to see the transition.

OBSERVED RESULT
Kdenlive plays up to the overlap zone, then stops and the program crashes.


EXPECTED RESULT
It should play the transition.


SOFTWARE/OS VERSIONS
Operating System: Manjaro Linux 
KDE Plasma Version: 5.15.4
KDE Frameworks Version: 5.57.0
Qt Version: 5.12.3
Kernel Version: 4.19.36-1-MANJARO
OS Type: 64-bit
Processors: 8 × Intel® Core™ i7-8550U CPU @ 1.80GHz
Memory: 23,3 GiB of RAM


ADDITIONAL INFORMATION
Debug info in the terminal ends with:
[mpegts @ 0x7f61c6a8de00] PES packet size mismatch
[mpegts @ 0x7f61c6a8de00] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6ab44c0] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[mpegts @ 0x7f625bac9a40] PES packet size mismatch
[h264 @ 0x7f6259477740] co located POCs unavailable
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[mpegts @ 0x7f61c6aca500] PES packet size mismatch
[h264 @ 0x7f61c6a924c0] top block unavailable for requested intra mode
[h264 @ 0x7f61c6a924c0] error while decoding MB 14 0, bytestream 236376
[h264 @ 0x7f61c6ab3640] top block unavailable for requested intra mode
[h264 @ 0x7f61c6ab3640] error while decoding MB 17 0, bytestream 26609
[h264 @ 0x7f61c577e440] top block unavailable for requested intra mode
[h264 @ 0x7f61c577e440] error while decoding MB 34 0, bytestream 244905
Assertion src->f->buf[0] failed at libavcodec/h264_picture.c:71
[1]    16119 abort (core dumped)  kdenlive