QLab video hangs (v4.1.5 warning)

[Mark Chadwick]

Hi,

I have a show touring the UK currently that has been experiencing critical issues with QLab, specifically version 4.1.5 where videos over 15minutes long will freeze, hang or stutter during playback and sometimes crash.

The issue isn't necessarily replicate-able, doesn't happen at the same time, during the same cues. Videos can be pro res or h264 mp4, but shorter videos have been playing fine. Qlab workspace remains responsive and doesn't hang. Audio continues to output, but video outputting to a separate surface will hang or freeze. Once this created a critical workspace crash.

I created a showfile in 4.0.11 and playback has been completely solid for months of testing and development. I handed over the show to the client last week. It ran fine in half a days rehearsal but during actual performance certain videos began freezing and hanging.

The tour has been running QLab 4.1.5 on a pair of Mac Minis, on OS Sierra 10.12.6. 

They both take midi commands to fire simultaneously for redundant backup. Often the video output will hang or freeze on just one machine, but on one occasion both machines hung at exactly the same time.

They were provided with different copies of some video content in various codecs and as a means of testing. They built a new showfile from scratch on site and encountered the same issue. This demonstrates it is not a bug in the showfile I created specifically, and different codecs demonstrate it is not caused by the videos specifically.

For the next level of testing, they rebuilt the show in Version 3 and it has run completely stable. As I have not been able to replicated the issue on my setup using v4.0.11, it looks to me like there is an issue with the latest version of QLab which they have been using.

I am still trying to get the console logs from them, but their main goal has been achieving a stable show currently.

Their setup is as follows:

Midi Controller + KVM > Mac 1 & 2 > Output 1 HDMI (Surface 1) to Projector (1440x1080) / Output 2 Thunderbolt-DVI(Workspace) local surface for monitoring.

The Mac Minis have 16gb Ram, so its not a memory issue.

Currently as they have some stability they're happy using version 3 for playback of the videos over 10minutes length, whilst using 4.1.5 for the main show of  jpeg and short video cues, which completely circumvents the ability to run backup. I don't think this situation is ideal. 

So for now, a gentle (personal) warning of caution with critical show content and playback in 4.1.5, (I've never like using the latest edition of software, for this very reason.)

[Jim Suttie]

I have also experienced a video problem with a show this past weekend with video using 4.1.5.

I have just begun troubleshooting this and noticed this post.

Our problem however was with video speeding up to the point that the video finished around half way through the audio track. The video and audio are separate cues in a start all children simultaneously group. I have around 12 similar group cues in the setup and this issue arose on 2 out of the 12.

My first thoughts are that its a hardware issue however I am unable to consistently reproduce this problem.

Investigations continue!

Jim

[Chris Ashworth]

Hi Jim,

This is a software bug introduced in 4.1.5 (when trying to fix a different issue).

I have rolled back the change in this beta, if you can confirm it works for you:

https://figure53.com/temp/QLab-4.1.6-b3.zip

Our current plan is to try to release 4.1.6 soon, possibly later today, to resolve this issue.

So far the reports I’ve heard are all related to a video cue being paused for a while before it was restarted — does that apply in your case?

Best,

Chris

[Jim Suttie]

It seemed to me that the video started OK, after around 15 seconds speeded up to the end of the video, waited till the audio file in the group finished then moved on to the next group in the show sequence that played out just as as expected. The total length of the group cue affected is 5m 12s.

It seems random as I have been unable to reproduce the problem.

Still trying though.

Thanks,

Jim

[Jim Suttie]

Hi Chris,

I installed the 4.1.6 updated, tested my setup extensively and all seems to work as expected.

Many thanks for your very prompt solution.

Best wishes,

Jim