Logitech C250 camera has too long decriptors.

[wimpie]

Hallo Bret,

I am already familiar with isochronous transfers and how to obtain an image from the Logitech C250 Camera using OS/2. This weekend I decided it was time to try and use your drivers to do the same using PCDOS. Unfortunately there were no interfaces shown at all when I used USBUHCI ADDRESSES and when I used USBUHCI DESCR only about 800 bytes of the descriptors were correctly shown. This camera has a total descriptor length of 1050 bytes. Is this a known limitation of your drivers? And if so are you willing to upgrade that?

In the meantime I already succeeded to try and obtain an image from my Sonix USB PC Camera using your drivers. In fact I found your API very easy to use. The disadvantage of this camera is that it supplies an image in bayer format whereas the Logitech C250 Camera is UVC compliant and supplies YUY2 and MJPG formats. My simple test program displays the raw bayer pixels directly on screen as a greyscale image.

Regards, Wim.

[Bret]

Unfortunately there were no interfaces shown at all when I used USBUHCI ADDRESSES and when I used USBUHCI DESCR only about 800 bytes of the descriptors were correctly shown. This camera has a total descriptor length of 1050 bytes. Is this a known limitation of your drivers? And if so are you willing to upgrade that?

Yes, the next version of USBUHCI will fix that. At the time I released the version you're using now, the biggest descriptors I found on any of the devices I had seen were about 500 bytes, so I figured 800 would be big enough. Since then, I've actually seen a device that rolls in at about 1200 bytes, so In the experimental update I'm working on now I've increased the max size to 1600 bytes. I hope that's big enough to handle any device someone might want to use -- if anybody sees anything bigger, please let me know.

I'm still several months away from officially releasing any updates to the programs, though. Never enough time to work on this stuff.

In the meantime I already succeeded to try and obtain an image from my Sonix USB PC Camera using your drivers. In fact I found your API very easy to use. The disadvantage of this camera is that it supplies an image in bayer format whereas the Logitech C250 Camera is UVC compliant and supplies YUY2 and MJPG formats. My simple test program displays the raw bayer pixels directly on screen as a greyscale image.

That' sounds pretty cool. FYI, I've never actually tested anything with isochronous transactions, so if you actually get it working I think you may be the first.

[wimpie]

I'm still several months away from officially releasing any updates to the programs, though. Never enough time to work on this stuff.

I understand.

That' sounds pretty cool. FYI, I've never actually tested anything with isochronous transactions, so if you actually get it working I think you may be the first.

See screen capture. On the actual vga screen it looks worse.