Problem with IMX415 USB camera

[admin]

Hi,

firstly, sorry about the downloads problem - I added some fancy footwork in Cloudflare a while back to try to make sure the installer downloads got cached properly and my server side code didn't handle the older four digit build numbers properly. That's now fixed, so you should be able to download old versions again.

When you say you are testing with the driver installed by AltairCapture, which choice are you choosing in the device menu in SharpCap? For it to be a comparable test to your webcam it would have to be the 'AltairCam' or similar entry in the 'DirectShow Cameras' section. I can't seem to find that AltairCam direct show driver at the moment, but if you may have it from an older install of the Altair software. I have the equivalent ToupCamAstro directshow driver installed as shown below.

Screenshot 2026-02-18 140530.jpg (32.9 KiB) Viewed 401 times

So, assuming you are using that AltairCam directshow driver and getting slow frame rates then I am starting to think that it might possibly be something to do with your Windows environment, as I am still seeing good frame rates with the ToupcamAstro directshow option - I have now tried with a few different ToupTek cameras.

Still, if we can pin down the point where the change in behaviour happened (and it isn't the big 'rewire DirectShow a different way' change) then I might be able to resolve the problem.

thanks,

Robin

[perdrix]

Ooops,I thought i'd selected this:

AltairCam.png (3.41 KiB) Viewed 390 times

when I ran the test on the lappie I used for imaging, but when I re-tested just now I realised I had tried originally with the old DS Altair driver which I hadn't removed. My bad!

So the GP224C is working correctly.

Apologies, David

[perdrix]

I DLed 4.0.7888 (64 bit) and have to report that it has the same problem as 4.1. So it looks like something that will be a bit trickier to solve.

Given that, should I post the camera to you? If yes, please email me offline with your postal address and I will pack it up and send it to you.

David

[admin]

Hi Dave,

I'm still worried this is an enviromental issue on your PC - your test with the AltairCam DirectShow driver was actually useful, since it revealed that camera also dropped to 0fps at a much lower resolution and with completely separate code on the camera side. My testing with the touptek directshow comes up fine and the touptek and altair ones are basically only different in terms of branding...

Can you test on a relatively clean alternative PC? Perhaps in a VMWare or VirtualBox VM on freshly installed Windows? One thing that can happen is that other video related software can install its own DirectShow filter components, which in some cases can get picked as the way to connect up the components needed to connect a video source like the camera to an application like SharpCap. I've seen cases before where having software package X installed caused that exact sort of problem for DirectShow cameras and uninstalling it fixed the issue (unfortunately I can't recall what 'X' was...).

If that doesn't get anywhere, are you coming to the PAS show in a couple of weeks? I will be there and it's a good opportunity to plug the camera into my laptop and see if the issue shows up - if it does I can take the camera away to test knowing I can repro the issue then post it back to you. If it doesn't have an issue then we are a bit stuck mind you...

cheers,

Robin

[perdrix]

I have already tested on another system, got the same problem. I am sort of planning on going to Stoneleigh for the show, but I am quite happy to post it (it is already packed and just needs a label).

Is there any magic environment variable I can set to persuade SC to log what's happening in gory detail?

D.

[admin]

Hi Dave,

to be honest, no, there isn't any additional logging for this that you can enable on the installed version. There are some things that I can do in the debug version in my testing, but this is an odd failure mode for a webcam - mostly if they are going to fail they fail during setup of the camera, not after setup.

Will ping you some postage details.

cheers,

Robin

[admin]

Hi,

just an update on this one in case anyone else runs into the issue. Dave was kind enough to post me his camera, and the problem can be cured by any of the following options

1) Switching the camera from MJPG into YUY2 mode

2) Increasing exposure to 0.25 or 0.5s

3) Ticking the 'Use preview pin for webcams ...' option in the 'Cameras' section of the SharpCap main settings (requires camera close/reopen)

It seems that something in DirectShow decides to limit the frame rate delivered to SharpCap when using shorter exposures on this camera in MJPG and using the preview pin.

cheers,

Robin