Elgato Cam Link 4K (HDMI input) webcam not detected

[Daniel Pocock]

I have an Elgato Cam Link 4K HDMI input.  It works fine with guvcview
and OBS Studio.

Jami says "No camera detected"

Jami version 20210104.4.dda80df~ds1-1


$ v4l2-ctl -d /dev/video0 --all

Driver Info:
        Driver name      : uvcvideo
        Card type        : Cam Link 4K: Cam Link 4K
        Bus info         : usb-0003:01:00.0-1
        Driver version   : 4.19.132
        Capabilities     : 0x84a00001
                Video Capture
                Metadata Capture
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04200001
                Video Capture
                Streaming
                Extended Pix Format
Media Driver Info:
        Driver name      : uvcvideo
        Model            : Cam Link 4K: Cam Link 4K
        Serial           : 000455561D000
        Bus info         : usb-0003:01:00.0-1
        Media version    : 4.19.132
        Hardware revision: 0x00000000 (0)
        Driver version   : 4.19.132
Interface Info:
        ID               : 0x03000002
        Type             : V4L Video
Entity Info:
        ID               : 0x00000001 (1)
        Name             : Cam Link 4K: Cam Link 4K
        Function         : V4L2 I/O
        Flags         : default
        Pad 0x01000007   : 0: Sink
          Link 0x0200000d: from remote pad 0x100000a of entity
'Processing 2': Data, Enabled, Immutable
Priority: 2
Video input : 0 (Input 1: ok)
Format Video Capture:
        Width/Height      : 1920/1080
        Pixel Format      : 'YUYV' (YUYV 4:2:2)
        Field             : None
        Bytes per Line    : 3840
        Size Image        : 4147200
        Colorspace        : sRGB
        Transfer Function : Default (maps to sRGB)
        YCbCr/HSV Encoding: Default (maps to ITU-R 601)
        Quantization      : Default (maps to Limited Range)
        Flags             :
Crop Capability Video Capture:
        Bounds      : Left 0, Top 0, Width 1920, Height 1080
        Default     : Left 0, Top 0, Width 1920, Height 1080
        Pixel Aspect: 1/1
Selection: crop_default, Left 0, Top 0, Width 1920, Height 1080, Flags:
Selection: crop_bounds, Left 0, Top 0, Width 1920, Height 1080, Flags:
Streaming Parameters Video Capture:
        Capabilities     : timeperframe
        Frames per second: 25.000 (25/1)
        Read buffers     : 0
                     brightness 0x00980900 (int)    : min=-128 max=127
step=1 default=0 value=0
                       contrast 0x00980901 (int)    : min=0 max=255
step=1 default=128 value=128
                     saturation 0x00980902 (int)    : min=0 max=255
step=1 default=128 value=128
                            hue 0x00980903 (int)    : min=-128 max=127
step=1 default=0 value=0