I have an ElGato capture device that doesn’t work with Linux - it’s the one right before the model that does work but is significantly more expensive. Maybe this can help me write a driver for it …
Driver adventures for a 1999 webcam
11–20 of 78 posts
Re: Driver adventures for a 1999 webcam
#12Reminds me when I had to read barcodes from a USB-connected barcode scanner on a Mac. The manufacturer supplied a closed-source library which only supported PPC code and they told me that they lost the source code, so I couldn't easily add intel support.
In the end I sniffed the USB protocol of the windows driver and was delighted to see how they abused the control endpoint rather than setting up proper data endpoints.
I was so happy when my Mac application was able to talk to the scanner and, compared to windows, completely without any driver installation thanks to user-space IOKit on macOS.
Writing software to make hardware beep is even more fun than writing software that doesn't involve hardware making noise.
Re: Driver adventures for a 1999 webcam
#13I have so many strange devices since my adventures in computers began. This has inspired me to dig them out of the plastic containers i have relegated them to and get some running again. Thank you for the write up!!!!
Re: Driver adventures for a 1999 webcam
#14Ugh I wish v4l2loopback was in the upstream kernel...
Re: Driver adventures for a 1999 webcam
#15Reminds me when I had to read barcodes from a USB-connected barcode scanner on a Mac. The manufacturer supplied a closed-source library which only supported PPC code and they told me that they lost the source code, so I couldn't easily add intel support. In the end I sniffed the USB protocol of the windows driver and was delighted to see how they abused the control endpoint rather than setting up proper data endpoint…
> In the end I sniffed the USB protocol of the windows driver and was delighted to see how they abused the control endpoint rather than setting up proper data endpoints.
Is there a better way to implement this? They seem to use it for any non-standard feature. My laptop's keyboard uses the control endpoint to control the LEDs.
Re: Driver adventures for a 1999 webcam
#16There is a lot you can do to improve the quality of the image. This camera has a very early CMOS sensor, which suffered from huge pixel-to-pixel variation. By characterizing each pixel (which you can do by taking dark field and flat field images), you can correct for this variation, and get an image that looks much less noisy. There are also various algorithms to undo the Bayer filtering, with tradeoffs between sharpness, color accuracy and performance.
Re: Driver adventures for a 1999 webcam
#17Oh, the 'I took it home already' feeling. I had a really bad case of this last week, bought a 17 KW solar inverter for a relatively small amount of money and lugged it home, all 50 Kg of it. It worked when it was taken off the wall according to the seller, but on plugging it in on my end it didn't work, though the display lit up and it seemed to work it wasn't making any power. Normally you'd return it as defective and that would be that but this thing is heavy and it was far away.
Long story short: the seller was a trustworthy fellow and definitely did not try to pull a fast one on me. What happened is that during assembly in the factory or a later repair someone smashed the lid into the main circuit board, almost but not quite tearing off one of those IDC headers for flat cable. Bits of it were rattling around in the case which already had me suspicious upon unloading it. That must have been quite the impact, those things don't normally break. The vibration of the transport across 200 km in a car with a stiff suspension did the rest and dislodged the cable completely. Plug the cable back in and it still worked, so I guess I got really lucky. It's been on the wall and has been making power for the last 3 days without any errors.
Re: Driver adventures for a 1999 webcam
#18There is a lot you can do to improve the quality of the image. This camera has a very early CMOS sensor, which suffered from huge pixel-to-pixel variation. By characterizing each pixel (which you can do by taking dark field and flat field images), you can correct for this variation, and get an image that looks much less noisy. There are also various algorithms to undo the Bayer filtering, with tradeoffs between sharp…
That's a very neat trick. In two decades of messing around with webcams we never clued in to that, and I'm pretty sure that this may well be one of the reasons why we had noise issues when using our very early bluescreen implementation.
Re: Driver adventures for a 1999 webcam
#19There is a lot you can do to improve the quality of the image. This camera has a very early CMOS sensor, which suffered from huge pixel-to-pixel variation. By characterizing each pixel (which you can do by taking dark field and flat field images), you can correct for this variation, and get an image that looks much less noisy. There are also various algorithms to undo the Bayer filtering, with tradeoffs between sharp…
Maybe it's subjective, but the screencap from XP seems to show a much higher quality image. It seems there's still room for improvement. Awesome work regardless!
Re: Driver adventures for a 1999 webcam
#20There is a lot you can do to improve the quality of the image. This camera has a very early CMOS sensor, which suffered from huge pixel-to-pixel variation. By characterizing each pixel (which you can do by taking dark field and flat field images), you can correct for this variation, and get an image that looks much less noisy. There are also various algorithms to undo the Bayer filtering, with tradeoffs between sharp…
The mentioned qc-usb driver seems to do some filtering.
IIRC when I played with that 15-20 years ago qc-usb produced distinctly blurry images with slightly washed out colors, while the original windows driver produced images that are sharp, very noisy and with somewhat unnaturaly vivid colors.