Bug 356185

Summary:	When clicking on the timeline, the monitor doesn't update until play is pushed
Product:	[Applications] kdenlive	Reporter:	Kubuntiac <user581>
Component:	User Interface & Miscellaneous	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED DUPLICATE
Severity:	minor	CC:	qubodup
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Ubuntu
OS:	Linux
Latest Commit:		Version Fixed In:	15.12.0
Sentry Crash Report:

Description Kubuntiac 2015-12-02 07:11:22 UTC

Any time I click somewhere on the timeline, the playhead marker moves to the correct place, but the image in the monitor doesn't update, making it difficult to correctly place the playhead on the timeline.

When pushing play, however, the monitor plays correctly from where the playhead was placed on the timeline.

I'm using version 15.11.80 from vpinions ppa on Ubuntu 15.10 64 bit with the Plasma desktop.

Reproducible: Always

Steps to Reproduce:
1. Place a clip on the timeline
2. Click somewhere on the timeline
3. Click smoewhere else on the timeline

Actual Results:  
The project monitor stays the same

Expected Results:  
The project monitor updates each time the playhead is moved by clicking somewhere else on the timeline

Comment 1 qubodup 2015-12-02 12:32:12 UTC

@Kubuntiac what video file format are you using? Does the video file have any strange properties? Does it play back properly in VLC and other media players? Can you seek it properly or does seeking cause freezes or A/V desync?

catalyst-hook 15.9-6
catalyst-libgl 15.9-2
catalyst-utils 15.9-2
mlt 0.9.8-3
qt5-base 5.5.1-3
kdenlive git describe --tags --always
v15.11.80-53-g0918054

I can confirm this or a similar issue with recent git, however only when using an apparently broken mkv video* and apparently only a low zoom levels (1 or 2). The final result of the issue is that Kdenlive freezes after clicking around the timeline less than 10 times.

Video: https://youtu.be/r1_y-rJ8Oo4

- The issue can be reproduced when not recording a screencast as well.
- Rewriting the container (ffmpeg -i in.mkv -c copy out.mkv) does not solve the issue.
- Reencoding to mp4 solves the issue. The video is still broken somehow (clicking in the first half, will start the music at the beginning, no matter where to click and it will show a static image but the right half is useable and it does not cause a freeze.

*The broken-ness of the video appears to be that audio and video are somehow out of sync perhaps and video players either don't play back anything for a while but skipping seems to help and seeking back only allows to go back to about 3m40s of the total >9m of video. Here is the broken pinball.mkv file: https://app.box.com/s/mwgo2r68oi5221l7g1o0hvijoj7qyu0l

Comment 2 Kubuntiac 2015-12-12 00:11:22 UTC

It's an H264 mp4 recorded on my Motorola Android phone using the default camera app. I've also tried and gotten the same result using mp4 files (presumably h264) recorded in the opensource Telecine Android screenrecording app.

Comment 3 Kubuntiac 2015-12-12 00:13:41 UTC

I've switched to vpinions packages and using:
Version 15.11.90
KDE Frameworks 5.15.0
Qt 5.4.2 (built against 5.4.2)
The xcb windowing system

I still get this problem.

Comment 4 Kubuntiac 2015-12-12 00:16:39 UTC

Just realized this is a duplicate of:
https://bugs.kde.org/show_bug.cgi?id=352489

When I reduced MLT threads from 3 to 1 and restarted Kdenlive, the problem goes away.

*** This bug has been marked as a duplicate of bug 352489 ***