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alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Holy PnP: A Media Device that Loads & Works 1st Time without Config

25 years ago with Windows I got used to being able to load hardware & have it work without too much bother; usually. Or at least, that is the bright memory of youth. With Linux I love it but, oh my! How often the tale of "only Window$ drivers available" and much wailing & gnashing of teeth in the Valley of the Trent. So, how pleasant to be able to deliver the tale of no-config necessary for, of all devices that normally fail, a video/audio web-camera. I give you: YIMONA Linux WebCam with Microphone (I bought it from Amazon and no, I have zero financial interest in promoting this to you):

This is what happened when I plugged it in:

[481612.084437] usb 1-1.3: new high-speed USB device number 6 using ehci-pci
[481612.546534] usb 1-1.3: New USB device found, idVendor=1bcf, idProduct=2cc9, bcdDevice= 9.19
[481612.546556] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[481612.546564] usb 1-1.3: Product: USB 2.0 Camera
[481612.546571] usb 1-1.3: Manufacturer: BC-230918-K
[481612.881352] usb 1-1.3: USB disconnect, device number 6
[481613.027528] mc: Linux media interface: v0.10
[481613.104459] usb 1-1.3: new high-speed USB device number 7 using ehci-pci
[481613.225308] videodev: Linux video capture interface: v2.00
[481613.334323] usbcore: registered new interface driver snd-usb-audio
[481613.388104] usbcore: registered new interface driver uvcvideo
[481613.432439] usb 1-1.3: device descriptor read/64, error -71
[481613.838737] usb 1-1.3: New USB device found, idVendor=1bcf, idProduct=2cc9, bcdDevice= 9.19
[481613.838754] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[481613.838761] usb 1-1.3: Product: USB 2.0 Camera
[481613.838766] usb 1-1.3: Manufacturer: BC-230918-K
[481614.064887] usb 1-1.3: Found UVC 1.00 device USB 2.0 Camera (1bcf:2cc9)
[481614.113270] input: USB 2.0 Camera: USB 2.0 Camera as /devices/pci0000:00/0000:00:12.0/usb1/1-1/1-1.3/1-1.3:1.0/input/input11
[481614.167675] usb 1-1.3: Warning! Unlikely big volume range (=4096), cval->res is probably wrong.
[481614.167686] usb 1-1.3: [5] FU [Mic Capture Volume] ch = 1, val = 0/4096/1

I've initiated a small-claim in the courts and without warning was posted a link for a remote hearing the next day. I was asked to login at 10am & read the email at 2pm that day (it was posted at 4pm the previous day). I had zero hardware for a remote hearing, and hence the order.

The Courts & Tribunals service has a page How to join Cloud Video Platform (CVP) for a video hearing (the link to test your equipment is at the bottom of that page; [later update]: please refer to note#2 in post#2 if you are non-UK).

Everything worked first time, zero config required. Wow! I do already have V4L2 installed (video for Linux), and that may be a requirement, I do not know.

It states Chrome as a requirement. I used Chromium under Daedalus.

I'm now waiting for a replacement Hearing date.

Hope that was interesting.

Last edited by alexkemp (2024-01-11 08:17:08)

alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

Note #1:
Both the Amazon product link + img link in post#1 come from my browser history in buying this product. Please report if either fails for you so that I can search out generic links to replace them.

Note #2:
The gov.uk CVP page should be available for non-UK visitors. I'm less certain whether the try-it-out-live page linked on that page will work for non-UK folks. Do drop a post here stating whether either worked for you.

Note #3:
I came across Guvcview, which is a useful UVC-based utility to check a webcam which also has snapshot/record video buttons. It is available in the repository:

$ apt search Guvcview
Sorting... Done
Full Text Search... Done
guvcview/stable,now 2.0.8-2 amd64 [installed]
  GTK+ base UVC Viewer

libguvcview-2.1-2/stable,now 2.0.8-2 amd64 [installed,automatic]
  GTK+ base UVC Viewer - runtime

libguvcview-dev/stable 2.0.8-2 amd64
  GTK+ base UVC Viewer - development files

Last edited by alexkemp (2024-01-11 10:16:33)

aluma

Member

Registered: 2022-10-26

Posts: 533  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

Maybe I don't understand something.
The v4l subdeck is included in the Linux kernel. Usually webcams use its driver and there are no problems, at least I didn’t have any problems with them.
In addition to the site gov.uk, there are many others that allow you to check the camera, for example
https://webcamtests.com/
Or just turn on the video from the webcam in the media player, without any Internet connection

P.S. Lastly, I don't think it's a good idea to use the site gov.uk unnecessarily. Government services have enough to worry about without DDoS attacks.

Last edited by aluma (2024-01-11 10:32:01)

alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

Hi aluma.

It is simple enough. I've never used a webcam before (40+ years using a computer). Previous Linux reports on webcams are that they suck. I'm having to educate myself all about them. After your post I discovered that the V4L API is in the kernel (did not know that - which kernel was it introduced with?).

The point of the gov.uk site is that CVP will be the specific app that I will need to use for the court (no options), so I used it to make sure that both me & the hardware would function in those circumstances. It also tested the 'cam for me. Then afterwards I thought "Hang on. It may be UK-only" so put the caveats in. Another point is that this is all new for small-claims, so it may well be important to document for the future, and I thought that others may spot the ignorance of a court employee not thinking that perhaps someone may need more notice than a 4pm email.

Last edited by alexkemp (2024-01-11 10:38:04)

aluma

Member

Registered: 2022-10-26

Posts: 533  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

Good health alexkemp !
I don't know when v4l was included in the kernel. My desktop has an ancient (10 years old) usb webcam, still 640x480. Even in those days, she worked without problems and I observed my face in some KDE3 program.

Regards.

Last edited by aluma (2024-01-11 10:58:20)

alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

The v4l subdeck is included in the Linux kernel. Usually webcams use its driver

An API is not a driver.

In my reading I notice many mentions of laptops with builtin webcams. If one of those is supplied with Linux (unlikely, I would have thought) then it would come with a driver that would utilise the V4L API. Otherwise not.

The main problem with cheap devices for Linux is not the driver but the way that so much (so-called) hardware-processing is actually off-loaded to the local CPU rather than handled by the hardware. That is the reason for so much "non-free firmware" in the apt sources.list. The dirty secret that is not mentioned there is that this is actually 'non-free firmware-originally-designed-for-Windows'.

You can see some of what I'm talking about in this PDF about modems & DSPs ("Digital Signal Processing"). On Page 9.3 it states:

A simplified block diagram for a V.90 analog modem is shown in Figure 9.3. The diagram shows that the bulk of the signal processing is done digitally. Both the transmit and receive portions of the modem subject the digital signals to a number of DSP algorithms which can be efficiently run on modern processors.

(DSPs are also used in sound processing)

The point of that paragraph is that DSP's are supposed to be specialised hardware chips contained within the modem. But no - that is too expensive. So instead the modem contains a cheap EEPROM which loads external firmware, and that causes the modem to use the local laptop cpu to run the DSP algorithms. Now, in the 1990s when this was all first originated there was ONLY Windows firmware, and Linux & Mac & all other OS had to go hang themselves. Now, after 25 years, we do actually have some firmware grudgingly provided (but no code, so it is non-free). Also, all updates arrive at Windows first.

But, it seems that my web-cam actually contains all necessary hardware. Hooray!

alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

I don't know when v4l was included in the kernel

It turns out to be 2002. It does also include drivers as well as an API.

aluma

Member

Registered: 2022-10-26

Posts: 533  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

About drivers and more
https://help.ubuntu.com/community/Webcam
https://www.berlios.de/software/linux-uvc/

alexkemp

Member

Registered: 2018-05-14

Posts: 292  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

Government services have enough to worry about without DDoS attacks.

Well, with 80 views in 24 hours that is, of course, a near certainty (if this not obviously irony, then consider that I am a mod at SFS and in mid-December the Stats Page reported 2m queries daily; now that gets close to a DDOS).

Thanks for the Berlios link. Reviewing my dmesg output I spotted that it was a UVC camera (have never come across that before):

[481614.064887] usb 1-1.3: Found UVC 1.00 device USB 2.0 Camera (1bcf:2cc9)

Last edited by alexkemp (2024-01-11 19:51:09)

aluma

Member

Registered: 2022-10-26

Posts: 533  

Re: Holy PnP: A Media Device that Loads & Works 1st Time without Config

@alexkemp
The main thing is that everything works for you and you are ready for the hearings.
The rest is little things...

Regards.