Transfer delay for a camera + video-capture-device

English Multimedia
1

gnome 46.0 wayland 64bit
Linux 6.10.7
AMD Ryzen™ 5 5600X × 12
Video capture device: <product description at Amazon>

The VC device does work and at the resolutions detailed. The camera is a Nikon d810; the USB port is v3.

Is it normal that there is about a 2 second delay between the camera and the display? Both VLC and Kamosa show the same delay regardless of the resolution selected in the camera.

Some data from “lsusb -vt”:

 /:  Bus 005.Port 001: Dev 001, Class=root_hub, Driver=xhci_hcd/4p, 480M
    ID 1d6b:0002 Linux Foundation 2.0 root hub
    |__ Port 004: Dev 002, If 0, Class=Hub, Driver=hub/5p, 480M
        ID 2109:2817 VIA Labs, Inc. 
        |__ Port 001: Dev 006, If 0, Class=Video, Driver=uvcvideo, 480M
            ID 534d:2109 MacroSilicon 
        |__ Port 001: Dev 006, If 1, Class=Video, Driver=uvcvideo, 480M
            ID 534d:2109 MacroSilicon 
        |__ Port 001: Dev 006, If 2, Class=Audio, Driver=snd-usb-audio, 480M
            ID 534d:2109 MacroSilicon 
        |__ Port 001: Dev 006, If 3, Class=Audio, Driver=snd-usb-audio, 480M
            ID 534d:2109 MacroSilicon 
        |__ Port 001: Dev 006, If 4, Class=Human Interface Device, Driver=usbhid, 480M
            ID 534d:2109 MacroSilicon
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@jimbobrae Worth a read here https://www.ideasonboard.org/uvc/faq/

3

Thank you. Using the info there, the video capture device is definitely a UVC device. None of the issues there seem applicable to mine; there is no mention of a processing delay.

With the camera providing a stream, it is displayed using VLC. If I wave my hand in front of the camera, 2 seconds later I see it in the host’s display. In the camera’s display, the wave is immediate.

4

@jimbobrae What is the graphics card in use, inxi -Gxxz

5 
 $ inxi -Gxxz
Graphics:
  Device-1: AMD Polaris 20 XL [Radeon RX 580 2048SP] driver: amdgpu v: kernel
    arch: GCN-4 pcie: speed: 8 GT/s lanes: 16 ports: active: DP-1
    empty: DVI-D-1,DVI-D-2,HDMI-A-1 bus-ID: 09:00.0 chip-ID: 1002:6fdf
    temp: 46.0 C
  Device-2: MacroSilicon USB Video
    driver: hid-generic,snd-usb-audio,usbhid,uvcvideo type: USB rev: 2.0
    speed: 480 Mb/s lanes: 1 bus-ID: 5-4.3.1:8 chip-ID: 534d:2109
  Display: wayland server: X.org v: 1.21.1.12 with: Xwayland v: 24.1.2
    compositor: gnome-shell v: 46.4 driver: X: loaded: vesa
    unloaded: fbdev,modesetting failed: nouveau alternate: nv,nvidia
    gpu: amdgpu display-ID: 0
  Monitor-1: DP-1 model: ASUS VG289Q1A res: 3840x2160 dpi: 157
    diag: 708mm (27.9")
  API: OpenGL v: 4.6 vendor: amd mesa v: 24.1.3 glx-v: 1.4 es-v: 3.2
    direct-render: yes renderer: AMD Radeon RX 580 2048SP (radeonsi polaris10
    LLVM 18.1.8 DRM 3.57 6.10.7-1-default) device-ID: 1002:6fdf
    display-ID: :0.0
  API: Vulkan v: 1.3.290 surfaces: xcb,xlib,wayland device: 0
    type: discrete-gpu driver: mesa radv device-ID: 1002:6fdf
  API: EGL Message: EGL data requires eglinfo. Check --recommends.
6

@jimbobrae So if you logout and switch back to X11 and login, does the issue remain?

7

As it happens, it was not the camera or the computer that was the cause of the delay:
It was the video capture device.

Despite all its other rather redeeming qualities, it was NOT a low-latency capture device. I purchased another UVC that proclaimed “ultra-low latency” and Voila! No noticeable delay.

 $ inxi -Gxxz
...
  Device-2: Integrated Express USB3.0 4K30 Video
    driver: hid-generic,snd-usb-audio,usbhid,uvcvideo type: USB rev: 3.0
    speed: 5 Gb/s lanes: 1 bus-ID: 6-4.1:8 chip-ID: 048d:9323
...

Not much difference from the first device. The USB bus speed is way faster.

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