Bug 360096

Summary:	15.13.0 git master - Monitor doesn't show video when switching to another tab, then back -- in certain layouts (video example included)
Product:	[Applications] kdenlive	Reporter:	Unknown <null>
Component:	User Interface & Miscellaneous	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED FIXED
Severity:	normal	CC:	null
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Kubuntu
OS:	Linux
URL:	https://youtu.be/ZuhXMiuHlQs
Latest Commit:	http://commits.kde.org/kdenlive/b5046ae634b8f0e05079606db8a1f45f1151d260	Version Fixed/Implemented In:
Sentry Crash Report:

Description Unknown 2016-03-04 23:17:40 UTC

See video in URL field for example.

When I was testing Kdenlive, I was playing back a clip in the timeline, then went to another tab, then back to the project monitor... but the screen was gray. No video.

The only way it comes back is if I switch between some combination of tabs to bring it back.

Reproducible: Always

Steps to Reproduce:
1. Set up, say, the undo history widget to the right of the Project Monitor.
2. Playback the project in timeline (or don't).
3. Click the undo history tab to open the widget, then click back to the Project monitor.

Actual Results:  
There is no video in monitor. Only gray.

Expected Results:  
Video to appear as normal.

Bug discovered on Kdenlive 15.13.0 latest git master build, Kubuntu 15.10 x64, KDE Frameworks 5.18.0 via Kubuntu backports ppa.

Comment 1 Jean-Baptiste Mardelle 2016-03-05 11:08:39 UTC

Hmm, cannot reproduce despite having the same config. Do you have a dual monitor setting (I mean physically 2 monitors attached to computer) ?

Comment 2 Unknown 2016-03-05 20:18:42 UTC

Ugh, gotta love the issues that can't be reproduced on the dev's end.

No sir, just a single monitor, set to 1920 x 1080, 60hz refresh rate.

I just tested a fresh install using the latest mlt .deb builds from Olivier Banus' ppa, and the latest Kdenlive git .deb builds from the Kubuntu-ci/unstable ppa. Same issue. :/

I'm also running two Nvidia GTX 660 graphics cards and the Nvidia 352.63 proprietary driver (the graphics cards are not SLI'd; Kubuntu is using the top one closes to the cpu on the motherboard, and ignoring the bottom one).

Comment 3 Unknown 2016-03-07 16:44:49 UTC

Last night, I tested for this issue using a laptop with Kubuntu 15.10 x64, KDE frameworks 15.18.0,  Intel graphics, and the  latest Kdenlive & mlt builds. Same issue on three separate machines.

Could it be something in the backports ppa? The bug might lie somewhere in my layout, too. I'll do some more testing.

Comment 4 Unknown 2016-03-07 16:48:26 UTC

Update: Whenever the two monitors are tabbed together, this issue doesn't happen.

Comment 5 Unknown 2016-03-08 17:21:05 UTC

Maybe it's the packages I'm using or the way I'm installing Kdenlive? These are the packages I'm using: https://www.dropbox.com/sh/g85jnkzxwnrrg8x/AAAzdTE6-hvfk0B02iC4Zzh3a?dl=0.

Could that be causing this issue at all? I'm experiencing this on all my devices I'm installing Kdenlive on, and their hardware is pretty diverse.

Comment 6 Unknown 2016-03-30 16:35:10 UTC

This issue doesn't seem to be present in the latest git master build via Kdenlive-master ppa for Ubuntu. I'll run a few more tests before marking this bug as resolved.

Comment 7 Jean-Baptiste Mardelle 2016-07-29 22:26:25 UTC

Git commit b5046ae634b8f0e05079606db8a1f45f1151d260 by Jean-Baptiste Mardelle.
Committed on 29/07/2016 at 22:25.
Pushed by mardelle into branch 'Applications/16.08'.

Fix monitor sometimes blank when switching tab

M  +1    -0    src/monitor/monitor.cpp
M  +3    -1    src/monitor/monitormanager.cpp

http://commits.kde.org/kdenlive/b5046ae634b8f0e05079606db8a1f45f1151d260

Comment 8 Unknown 2016-07-29 22:34:09 UTC

Excellent! Glad this was got resolved. :) Thanks JB.