Corner Pinning "From Pins" to "To Pins"

[FL K]

Hi there community and F53,

I am in a situation where we are constraint by distance to using a GoPro Wide as cam input,  on an angle, onto a recognisable 5x5 grid; Because of the Lens distortion and the angled aspect onto it, it was a bit of a challenge to get an acceptable outcome; at the moment we did it within a stage (send the camera cue to a syphon stage, reform the content in that stage, and then use a second cam cue with the said loop stage as the source for the final output.

I am getting somewhere with this method, but it is a bit clunky, as the camera is 16:9, and the target area appears naturally as a trapezoid within it to start with.

So, what I wanted to ask was - either via current tools/work-arounds, or as a feature request - whether either in stage warping, or as a plug in (though I find them harder to work with with the dials, not as intuitive), there is a chance to work with the concept of "From Pins" and "To Pins" - I used to use this a lot in After Effects with Red Giant Corner (Now rebranded with tracking as RG King Pin by Maxxon), and it makes live so easy when it comes to irregular shapes and shapes that are smaller than the entirety of the picture - demonstrated by someone here for a couple of minutes: https://www.youtube.com/watch?si=Wg0KMxC9Cm9_yaWe&t=277&v=wQXzff2UFEE&feature=youtu.be

I looked and could not find a good work around yet;

- Routing it through After Effects; you can get live feed FROM after effects via NDI, and there used to be a way to get live video in by frischluft, but that avenue seems gone: https://www.frischluft.com/lensfeed/index.php

- I guess one could "stack" another virtual stage via syphon or NDI internally, and use the first one to rectify/crop with overlap, creating a squarish with some leftovers, and then use the second to deal with the lens distortion/mesh warping?

Anyway, the absolute dream would be a way to have an input mesh (ideally with bezier and perspective, with freely configurable amounts of sub partitions including uneven ones), to then reform to an outer mesh...

Keen for all thoughts, both practical (now) and dream (future)...

Cheers,

Freddy

[micpool]

Reading your post, it struck me that you are missing a potential features of the video pipeline which could help a lot with what you are wanting to do.

If you are basically cropping  and corner pinning a 16:9 image to a square surface (5x5) then you can make a square stage. e.g 1080x1080

In the geometry tab of the camera cue you can move your 16:9 frame around the 1:1 stage to select the region of the GoPro image you are going to display.

In the Warping  tab of that stage you are now corner pinning that square area to your square surface. 

Mic

[FL K]

Hi Mic,

Thanks for your reply :)! I think either I am not getting what you are putting down, or you might have misread my (admittedly) convoluted explanation - let me rectify:

This is a very rough sketch of what I am dealing with, but - the outside outlines of this whole irregular quadrilateral would actually be bowed/bulging also as well as its perspective we are seeing.

Now, whether I make a smaller stage to contain what is in the 16:9 shot or not, the issue is that I want to "reverse" keystone, as opposed to grabbing the outside handles of the frame (if you go down that route, you keep have to iteratively go around each of the corners and bezier points, as every move of one affects the other through the perspective algorithm I think) - I want to define where the inside handles should be, to then re-map to a regular, square corresponding pins, if that makes sense - here demonstrated in a different software, on the left hand the "input" side, where you have the input image and where you have placed the "input" mesh points, and on the right hand side the "output" side, set to be a regular grid of 7x7 (one on each side to later crop to/discard) (this is what I believe the only realm that QLab is currently operating in - the warping of the output side):

So, I guess what I am trying to establish is - is there a comparable workflow that either exists now in QLab, or is desired/desirable/planned for the future, or is this way of working outside of the scope of what QLab can/wants to be?

Obviously, my example is a very specific need, so I understand if it is only me desiring this.

Cheers,

Freddy

[micpool]

On Sunday, November 30, 2025 at 1:58:49 AM UTC busy...@gmail.com wrote:

 I think either I am not getting what you are putting down, or you might have misread my (admittedly) convoluted explanation 

Yes I had misunderstood your query, and thought your GoPro was overhead and you were wanting to warp the overhead view of a square onto a tilted surface.

So what you are wanting to do is defish your GoPro  Wide Shot and then apply a 5x5 input mesh and warp that mesh to give an output of a regular 5x5 grid.

I don't think there is an easy way to do that in QLab.

You can do something similar in Mad Mapper, (I think your demo illustrations in your last email may have been made in that) but the defish is still tricky and you are dealing with over 50 points, 25 each in the input and output meshes.In fact you are using 128 points in your example because you are also warping the area outside of your grid.

I do think the fact that QLab restricts the input area selection on a stage that gets warped  to rectilinear areas is somewhat limiting, but looking at the number of controls and the amount of GUI elements that are used in MadMapper to even partially achieve a good result for your particular problem, perhaps that complexity is best dealt with by specialised mapping software in conjunction with QLab?

Mic

[FL K]

Yes to all that; it is asking quite a bit, and maybe not heartland QLab territory... OT, Madmapper does OK with this, but I discovered an annoying trait - you can't move input points without simultaneously moving the corresponding output point... so lots of double work instead of creating a neat grid to start with and just moving the 25 input points to suit... but hopefully they fix that...

Thanks for your time as always, Mic!

Freddy

[micpool]

On Sunday, November 30, 2025 at 1:43:24 PM UTC busy...@gmail.com wrote:

 OT, Madmapper does OK with this, but - you can't move input points without simultaneously moving the corresponding output point...

Doesn't deselecting this checkbox allow you to do this? 

 

[FL K]

Feeling like a right fool now, can't believe I did not spot this! Thank you Mic :)!