Techniques/hardware for cropping an image?

Does anybody know if the Extron 304 is capable of cropping an image? Thanks!

I have an Extron DVS 204, but I checked the manual and it’s the same as the 304 in this regard. It has the ability to change the horizontal and vertical centering as well as the horizontal and vertical size of the image. You can use the edges of the frame to crop out certain parts of the image (ie extend the image so that the menu bar from a computer is off the edge), but you can’t arbitrarily crop the image.

The 304 has an additional feature that allows you to zoom into the image without affecting the centering and size controls, and provides additional pan controls to move around while zoomed, but this still wouldn’t let you crop arbitrarily.

Hope this was helpful!

It absolutely was, thanks!

Follow-up question, what hardware out there allows for live cropping without the use of a laptop?

cardboard passepartouts over the display you’re rescanning
:face_with_hand_over_mouth:

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I think I might be able to give a better answer with a little more context, what kind of look are you trying to achieve?

What are you using as your input source, and what are you trying to crop from it? Do you want the cropped image to fill the frame, or do you want to leave blank space around the cropped image? Do you want to be able to reposition or resize the input image?

Sadly, I’m not aware of a dedicated video hardware device that can do live cropping on its own, but I am aware of some techniques that can be used to achieve the same effect.

The simplest and most flexible way would be to use a laptop: send your input video signal into a USB capture card (I like this one), open the video capture device in something like OBS studio (free) or Resolume Avenue/Arena (not free), where you can crop, move, and resize as you like, then send the output to a scan converter if you need it back in composite or S-Video for the rest of your signal chain.

Besides using a laptop, this functionality (cropping, moving, and resizing) can also be achieved by rescanning a display and using a cardboard mask over the display, as @pixelflowers suggested. If you want to manipulate it in a live context, I’d personally
recommend using a document camera and flat panel LCD display for this purpose (it’s also really nice for camera feedback :slight_smile:) I used a circular mask I had laying around, but using multiple pieces to create the edges of the mask would allow you resize the mask.

A different technique I’ve seen mentioned in an old video mixer user guide is using a camera and a cardboard cutout or mask to act as the key for the luma key of a video mixer, and then filling it with your input video. The example they gave was zooming into a heart shape printed on a piece of paper to create a heart shaped wipe for a wedding video. It’s kind of small, but you can see the composited output in the preview monitor on the left. This method does not allow you to reposition or resize the input video (although you could use a video scaler to do that before cropping), and it does use a whole video mixer, but it does open up a lot of possibilities for overlays and frames for your input video source, even printing gradients onto overhead transparencies for softer edges.

I like where this conversation is going, but we’re starting to get away from “Hardware video converters/scalers.” I don’t know how to split this into a new topic, but maybe one of the mods/admins could move this to a topic called “Techniques/hardware for cropping an image?” or something similar? Thanks in advance :slight_smile:

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right! thanks a lot for the input, and suggesting an appropriate title makes things easier.

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also: most any video mixer that allows you to select a ‘matte’ for 1 channel allows you to then use any wipes that come out from the sides of the image as a crop tool. i kind of have a feeling that this and/or tagboard masks would be the standard methods used

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On Panasonic MX10 and MX12, pretty sure the rectangle and circle wipes can both be positioned as well. (But it’s been forever since I’ve used mine so someone correct me if I’m wrong; neither in front of me at the moment to look.)

So you wouldn’t get precise control of the crop shape (2 choices: either a circle or a 4x3 rectangle), but you can control size and position (of crop; not position of cropped image).

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Some really interesting techniques, thanks everybody.
It’s funny that none of these mixers have a proper left/right/top/bottom cropping effect but I guess I’ve been doing this for ten years and it’s the first time this issue has come up.

To answer Clovis’ question, it was for the sake of projection mapping, but at the end of the day I’m going with my laptop and cropping through Isadora. The projection image and sheet got much more complex so even if cropping hardware existed I would need more maneuverability at this point.