[gentoo-user] guvcview - no video device (/dev/video0) found

[gentoo-user] guvcview - no video device (/dev/video0) found

[thelma]

Getting an error message when trying to start usb-cam:

guvcview
ENCODER: no video codec detected for VP9 (VP9)
ENCODER: no video codec detected for Theora (ogg theora)
GUVCVIEW: version 2.0.8
GUVCVIEW: couldn't open /home/joseph/.config/guvcview2/video0 for read: No such file or directory
V4L2_CORE: ERROR opening V4L interface: No such file or directory
GUVCVIEW (2): Guvcview error
	 no video device (/dev/video0) found
GUVCVIEW (Qt5): fatal error (0 devices detected)
GUVCVIEW (Qt5): creating error dialog

dmesg:

[935066.984348] usb 1-1.4: Product: Vega USB2.0 Camera
[935066.984350] usb 1-1.4: Manufacturer: Vimicro Corp.
[936075.049430] usb 1-1.4: USB disconnect, device number 47
[936080.312412] usb 1-1.4: new high-speed USB device number 48 using xhci_hcd
[936080.504291] usb 1-1.4: New USB device found, idVendor=0ac8, idProduct=0331, bcdDevice= 1.00
[936080.504296] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[936080.504297] usb 1-1.4: Product: Vega USB2.0 Camera
[936080.504299] usb 1-1.4: Manufacturer: Vimicro Corp.

-- 
Thelma

Re: [gentoo-user] guvcview - no video device (/dev/video0) found

[Andreas Fink]

On Sat, 13 May 2023 14:50:33 -0600
thelma@sys-concept.com wrote:

> Getting an error message when trying to start usb-cam:
>
> guvcview
> ENCODER: no video codec detected for VP9 (VP9)
> ENCODER: no video codec detected for Theora (ogg theora)
> GUVCVIEW: version 2.0.8
> GUVCVIEW: couldn't open /home/joseph/.config/guvcview2/video0 for read: No such file or directory
> V4L2_CORE: ERROR opening V4L interface: No such file or directory
> GUVCVIEW (2): Guvcview error
> 	 no video device (/dev/video0) found
> GUVCVIEW (Qt5): fatal error (0 devices detected)
> GUVCVIEW (Qt5): creating error dialog
>
> dmesg:
>
> [935066.984348] usb 1-1.4: Product: Vega USB2.0 Camera
> [935066.984350] usb 1-1.4: Manufacturer: Vimicro Corp.
> [936075.049430] usb 1-1.4: USB disconnect, device number 47
> [936080.312412] usb 1-1.4: new high-speed USB device number 48 using xhci_hcd
> [936080.504291] usb 1-1.4: New USB device found, idVendor=0ac8, idProduct=0331, bcdDevice= 1.00
> [936080.504296] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
> [936080.504297] usb 1-1.4: Product: Vega USB2.0 Camera
> [936080.504299] usb 1-1.4: Manufacturer: Vimicro Corp.
>

Do you have read/write access to /dev/video0? Try with:
ls -lh /dev/video*

Re: [gentoo-user] [SOLVED] guvcview - no video device (/dev/video0) found

[thelma]

On 5/13/23 22:31, Andreas Fink wrote:
> On Sat, 13 May 2023 14:50:33 -0600
> thelma@sys-concept.com wrote:
> 
>> Getting an error message when trying to start usb-cam:
>>
>> guvcview
>> ENCODER: no video codec detected for VP9 (VP9)
>> ENCODER: no video codec detected for Theora (ogg theora)
>> GUVCVIEW: version 2.0.8
>> GUVCVIEW: couldn't open /home/joseph/.config/guvcview2/video0 for read: No such file or directory
>> V4L2_CORE: ERROR opening V4L interface: No such file or directory
>> GUVCVIEW (2): Guvcview error
>> 	 no video device (/dev/video0) found
>> GUVCVIEW (Qt5): fatal error (0 devices detected)
>> GUVCVIEW (Qt5): creating error dialog
>>
>> dmesg:
>>
>> [935066.984348] usb 1-1.4: Product: Vega USB2.0 Camera
>> [935066.984350] usb 1-1.4: Manufacturer: Vimicro Corp.
>> [936075.049430] usb 1-1.4: USB disconnect, device number 47
>> [936080.312412] usb 1-1.4: new high-speed USB device number 48 using xhci_hcd
>> [936080.504291] usb 1-1.4: New USB device found, idVendor=0ac8, idProduct=0331, bcdDevice= 1.00
>> [936080.504296] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=0
>> [936080.504297] usb 1-1.4: Product: Vega USB2.0 Camera
>> [936080.504299] usb 1-1.4: Manufacturer: Vimicro Corp.
>>
> 
> Do you have read/write access to /dev/video0? Try with:
> ls -lh /dev/video*

No, it wasn't the case.
I had to add support for V4L in the kernel.

I'm surprised that there was no emerge note after emerging the package, that package needs V4L support in the kernel.