QLab syphon client too optimized (somehow) ?

[Jérôme Tuncer]

Hello there,

Quite a tricky problem to describe :

I'm witnessing a somehow strange behavior in QLab 5. Could have happened in QLab 4, not sure it's really version related...

I'm using Glypheo to stream a lot of text input to QLab via Syphon. I'm dealing with all the cosmetics stuff (fades, effects...) in QLab. I have a lot of other stuff going on in my QLab session (video files, sound input, output...) apart from this.

Whenever I start QLab, then Glypheo (or the other way around, FWIW), if I monitor Glypheo Syphon inputs from my workspace preferences, I only see blank inputs. I have to update Glypheo a few time to witness change in my input monitor windows in QLab. It's as if Syphon inputs in QLab were so optimized that frames get lost when an app (Glypheo in my case) "streams" Syphon to no actually active video input cue.

The actual consequence in my show being that if I display a video cue input from Glypheo through Syphon to an output, it is quite often an older Syphon frame that is displayed in my output. Glypheo has to be trigged a few time (i.e. get frames updated a few times) for QLab to receive the correct actual line of text.

If I monitor stuff going out of Glypheo through Syphon Simple Client, frames are updated immediately after Glypheo is started or line is being changed.

Just so you know : Glypheo is not a very "active" Syphon streamer. It will (from what I see) only update Syphon "frames" every time a new line of text is trigged. Hence its detected framerrate being very low...

I hope I'm being clear enough. It's actually easy to witness in real life, but hard to describe with a few paragraphs of text.

Don't hesitate to ask if you need more details to understand my issue.

Yours,

Jérôme

[Richard Williamson]

Doesn’t solve the underlying issue but fyi I usually use glypheo with NDI and qlab and don’t see this issue 

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On 26 Oct 2025, at 00:03, Jérôme Tuncer <jerome...@gmail.com> wrote:

Hello there,

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[micpool]

Richard,

Are you saying that you have seen this "underlying issue" with Glypheo and Syphon into QLab? I'm about to do an opera with surtitles using that set up, and haven't seen it yet, but if it is a thing then obviously I would want to avoid it..

Glypheo and QLab seems to be a regularly used combination, and if there is an issue with Syphon to QLab I'm surprised this is the first post on the subject?

Syphon is designed for the transport of video and still images, so it shouldn't be an issue.

Mic

[Richard Williamson]

Sorry - I wasn’t clear. I haven’t seen this issue - although I have had a few issues with glyoheo’s NDI feed stopping working and needing a restart of the app to fix, but this has never been a critical problem

I’ve just always used NDI as generally glypheo has its own operator 

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On 26 Oct 2025, at 11:52, micpool <m...@micpool.com> wrote:

Richard,

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[Jérôme Tuncer]

It's actually tricky to reproduce in a simple session but here goes one example that might demonstrate this behavior.

1. Start the 2 files (Glypheo and QLab), leave Glypheo alone.
2. Wait for QLab to discover NDI sources (takes a few seconds in my setup here)
3. Start cue number 1 in QLab

Expected behavior :

1. "actual text track 1 line 1" should be displayed with a 1s fade-in / out
2. "actual text track 3 line 3" should be displayed with a 1s fade-in / out

Result (at least here) : nothing is shown on the surface.

Next step :

1. Start cue number 2 in QLab

Expected behavior :

1. "actual text track 1 line 1" should be displayed with a 1s fade-in / out
2. "actual text track 3 line 3" should be displayed with a 1s fade-in / out

Result (at least here) : correct text is displayed.

Now, go back to cue number one : behavior is back to normal.

Maybe my computer is the only setup showing such behavior. I don't know. But in my true show session, it ends up being not so reliable.

I'll try switching to NDI only during tomorrow's rehearsal and keep you posted.

[Paul]

Just a thought, you do know that Glypheo numbers it's subtitles from zero?

So if you want the first line in your file you need to send OSC 

/goTo 0 

and to get line 2 you need to send /goTo 1

Also you need to put the Network cue before the Camera cue.  Tested your Workspace with 1000 entry Glypheo file and Syphon seems to work ok.

[Jérôme Tuncer]

Hey Paul,

Thanks for chiming in.!

Le lundi 27 octobre 2025 à 22:14:42 UTC+1, Paul a écrit :

Just a thought, you do know that Glypheo numbers it's subtitles from zero?

So if you want the first line in your file you need to send OSC 

/goTo 0 

and to get line 2 you need to send /goTo 1

Yes, I know that. I've been using Glypheo a lot in the past already (-;

 

Also you need to put the Network cue before the Camera cue.  Tested your Workspace with 1000 entry Glypheo file and Syphon seems to work ok.

Will try that. But I don't think it's really related to the exact symptom I'm witnessing.

I think the strange behavior I'm witnessing is not in any way related related to the amount of cues contained in the QLab and/or Glypheo workspace. It's related to the way things get instantiated/started.

If you happen to have time : What happens if you follow scrupulously my guidelines ? Specifically the first part :

 

1. Start the 2 files (Glypheo and QLab), leave Glypheo alone (i.e. don't clik on any subtitle, leave it on title 0)
2. Wait for QLab to discover NDI sources (takes a few seconds in my setup here, you might have to re-patch inputs in QLab)

1. Start cue number 1 in QLab

Expected behavior :

1. "actual text track 1 line 1" should be displayed with a 1s fade-in / out
2. "actual text track 3 line 3" should be displayed with a 1s fade-in / out

Result (at least here) : nothing is shown on the surface.

I'd be really curious so as to what happens on another computer than mine here.

[Paul]

Using your Qlab Workspace, after changing the video output counting and turning on 'Keep rending between cues" (Settings-Video- Edit Stage), running your cue number 1 I get

Panel 1 Line 1 fades in and out

Panel 3 line 2 fades in and out

but the first time I run it after open Glypheo I get nothing displayed. So I guess Glypheo needs "kick" to get something output - but that would be done in the rig check, so it's irritating, but I wouldn't regard that as a problem.

I haven't had time to try NDI.

In general if using Qlab for video other than subtitles, I would put the subtitles into QLab. That is much more flexible. Just use Glypheo when those are the only video display in use on a show. (did a show last year with about 700 subtitles in two languages in QLab which worked smoothly).

[micpool]

Richard,

I've now had a few issues with QLab using Syphon  on the same machine so tried NDI and also moving the Glypheo to a seperate machine and using NDI to QLab,  Every time I do anything, editing Panels, playing a cue etc. Glypheo crashes. Is there somewhere you can download earlier versions as I don't remeber this from last time I tried it. I'm using 1.4.9 on Sonoma with QLab 5.4.11 on M1 Macs. What configuraiton do you use successfully?

Thanks

Mic

[micpool]

The opera project that  I was working on which included Surtitles , is now up and running successfully. It included 5 surtitle screen areas so surtitles could be placed on a screen above the head of the singing performer, or a singing filmed character on screen..

I started programming this in  Glypheo running on the same machine and Syphoned  into QLab camera cues, moved to NDI streams running on a second computer,  but got totally frustrated whenever a character moved to a different position that I couldn't select a block of surtitles in Glypheo  and cut and paste them to a different track/screen position. The new export import features in Glypeo did not help very much as the implementation is very limited..

In the end I went back to doing everything in one QLab workspace and only needed to write half a dozen scripts to be able to import titles from a spreadsheet and convert blocks of cues to Glypheo style transitions (fast fade previous then   fastfade up new caption),  and a few other utility functions to emulate some of Glypheos other features and to handle batch changes of fonts and  sizes etc.

I had about 1000 surtitle cues of which half were automated in sync with video cues and half cued line by line manually to sync with live sections of the performance.

Whenever  I edited the video cues,   I had a couple of scripts to add or subtract to the prewait times for subsequent cues.

I am now strongly of the opinion that Surtitling in QLab, with a few suitable scripts to hand,  is for most uses a much more flexible and more efficient workflow than using a standalone captioning software solution. The sequence recording in QLab is great for syncing surtitles to prerecorded or clicked sections of performances. and the fact that spelling mistakes or small rewrites can instantly be corrected makes it much more flexible than rendering surtitles onto the actual video files.

If you think there is something that standalone Surtitle software can do more efficiently than QLab, I would be interested in hearing about it, to see if I can optimise my scripts to do it more efficiently in QLab!

Mic

[micpool]

On Tuesday, October 28, 2025 at 7:07:39 PM UTC micpool wrote:

I've now had a few issues with QLab using Syphon  on the same machine so tried NDI and also moving the Glypheo to a seperate machine and using NDI to QLab,  Every time I do anything, editing Panels, playing a cue etc. Glypheo crashes.

For the record, although this was the point at which, after wasting a few hours,  I moved my surtitling back to QLab, I did follow this up with the Glypheo team. The crashes were caused by NDI stream pixel dimensions that were not a multiple of 16. I believe this limitation has been fixed in a new version.

Mic

[micpool]

Here's a photo (credit: Anthony Robling) of my show!

Projection onto BP with 30 percent mirrored front surface.

[Richard Williamson]

Most times I need surtitles for a show it’s for theatre in another language, therefore I have a separate operator for surtitles so Glypheo is the best option - I also find Glypheo is much simpler for an operator to use, and I can show a non technical person how to go through and update it much more easily than I can QLab

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On 12 Nov 2025 at 16:43 +0000, micpool <m...@micpool.com>, wrote:

Here's a photo (credit: Anthony Robling) of my show!

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