Webcams

[Bert Coules]

I just replaced a very elderly, very cheap webcam with a higher-res but still mid-budget model. Is there any way of zooming the image to restrict its coverage? The camera itself doesn't use a dedicated driver and (ironically) I can't see a zoom option in Zoom, which is the software I use most often.

I thought there were third-part utilities to control a webcam but the ones I've looked at so have only filters and lighting adjustment rather than image size options.

Thanks.

[Bob Eager]

My Logitech cameras have a utility (downloadable) that does that stuff.

[Bert Coules]

Thanks for that. I almost went for a Logitech; probably should have. I must check out their range. Do they something decently-specced for around £40 - £50?

[The Natural Philosopher]

They do, yes

[jon]

The Microsoft Studio webcam is an excellent product, with full filter control.

[Bert Coules]

Including zoom?

Thanks, Jon.

[Paul]

And some are back in stock. Some models of Logitech disappeared for a year.

My computer store has some Brio cameras, even. One of the few 4K, USB3 cameras. The part number has changed, implying a new review will be needed to see how much different this one is. (Sometimes they change sensor or controller when the part number changes.)

The digital zoom function can cut a 640x480 surface from the main picture. I have the Logitech software issued with my camera and it works only in Windows 7. Updates to the software stopped, so the issues caused by Windows 10 were not fixed up. I get really weird resolution choices in Windows 10. If you boot the Windows 10 setup twice, the resolution choice dialog may give a different set of values than before, for the same piece of hardware. Whereas the Windows 7 which uses original Logitech software "just works".

Paul

[Bob Eager]

I have a couple of C525s, which are about £60. I need a webcam in the office and the workshop, hence the two; it's too much faff to keep moving them and setting up.

Not tried the microphone; I have Bluetooth Plantronics/Poly headsets.

[Bert Coules]

Thanks for that. Is it not possible to tighten the coverage but retain a

16:9 image ratio?

I'm using Windows 7, so the compatibility of the software with Win10 wouldn't be an issue for me,

[jon]

Zoom, Focus, Backlight, etc.

[jon]

For security, I use the free Contacam application that has movement detection and network transfer if required, or Amcap for general video capture....for video chat I use 'Wechat' (I have a Chinese friend). OBS is a good, free video application, but a bit too fiddly for me. All of these apps allow you to set the complete range of filters.

[Paul]

This was software custom-made for that webcam.

We don't know if that's a silicon function or a pure software emulation of same.

Some security cameras have all of this capability, inside the camera housing. You can specify AOI (Area Of Interest), and even have movement detection in a small area. Some security cameras can even have two AOI and the recording only records the AOI and not the bulk of the sensor bits. Making the recording more compact.

A webcam is unlikely to be that sophisticated. The sensor doesn't care, and these could be functions in the MAC.

This is one reason you have to review the camera documentation to see if the software has any useful enhancements. If this is a software emulation of an AOI, then the dimensions are programmable. But typically, the dimensions, the values, tend to adhere to canonical values. Where 640x480 is canonical and 720x480 is canonical. 123x456 would be a bodge and harder for the software framework to deal with. This is one reason why the table of values Windows 10 makes from my webcam are so strange. They're goofy 123x456 values, and you can see values in the Win10 listing, that have no matching entries in the USB config space coming from the webcam.

If the pixels are square, there's no problem cutting a

640x480 out of a 1920x1080. My camera software control allows panning around within the sensor surface, and when I conference with the doctor at the hospital, I center my head in the shot once I'm comfortable in my "studio chair". I can sit where I like, slouch if I want, then fix it with the software pan.

When we had our community Zoom meeting about flooding and drainage, most of the users were reasonably good at setting up their kit, but one gentleman didn't even manage to prop his webcam up securely on his computer and it kept falling off. And he did that over and over again - just some old fart like me, with only half of his marbles left :-) I didn't expect the meeting to be that well managed, but he took the cake for cluelessness. I was hoping the mod would just blank out his camera. For a guy like that, centering the image was outside his pay scale. He was still "figuring out how gravity works".

Paul

[Bert Coules]

Paul, thanks for that. My current webcam has the following characteristics when used for Zoom:

The default setting is 16:9 full screen at what looks to me like a resolution of 720.

I can switch to "original ratio" which widens the field of view vertically but not horizontally, giving a 4:3 image with black bars either side on the

16:9 Zoom window,

in 16:9 mode I can also switch to "HD" which increases the field both vertically and horizontally, thereby covering a greater area. The image is reported as 1900x1080 and shows a marked fish-eye effect at the sides. The coverage is reported in the camera's spec as 120 degrees.

What I'd like to achieve is a 16:9 HD image with a narrower angle of capture: hence my enquiry about zooming. I suspect that this is simply not possible with the model I'm using.

[Paul]

The 16:9 ratios are in the Blue color here.

854x480 ???

I've never seen that one before. Don't think you'd find that in USB config space either. But you can look. Since your cam is HD 16:9, it's still a possibility.

The 1280x720, there are some mid-range webcams where that is their native resolution.

The arbitrary scale capability is unlikely to be in the main menu of any application. The trick is, the proprietary camera software offers a separate popup control, and that's the one that allows digital zoom in and pan. And panning is the part of that which I mostly adjust.

If I did Zoom in Linux, I don't know if there's a dialog available like that or not. There is at least one auxiliary control (in guvcview?), but it controls things like focus and light level. And with my camera, it has advanced enough to have a tick box for "autofocus". But as for capture WxH, I don't think it has that on it.

*******

From the USB config space of my webcam...

Video Streaming MJPEG Frame Type Descriptor

160x120 176x144 320x240 352x288 640x480 800x600 960x720 ("UVC max" ???)

It doesn't even have an entry for native resolution. That's why Windows 10 jerks me around, only offering weirdo values up to around the 960x720. I think the camera might do 1600x1200 native - it's not an HD cam.

Any other values are software emulated.

I got those values using USBTreeView from Uwe. My cam shows up as a composite device.

It's only when I use the proprietary Logitech software, that values above "UVC Max" are made available.

One reason 640x480 is popular on a USB2 cam, is you get

30FPS there. At 1600x1200, my cam only does 5 FPS and the session looks pretty jerky. (And this is not a light level issue either, you can bump up the lighting and it does not help the rates.) This is why the 640x480 value in my room, would be popular - the cam doesn't slow down. On the product box, the product is listed as

Capabilities:

1600x1200 30FPS

But notice they did not say 1600x1200 @ 30FPS. It's because these two lofty figures are independent of one another. You can't get them both at the same time. You might have to shell out for a USB3 cam to get a bit more headroom. And then the computer software would have its share of issues with such things. High tech stuff is never a "smooth ride". Windows 10 wants me to be a "low res guy".

Paul

[Bert Coules]

Thanks for that, Paul.

That chart is fascinating.