Old ToUcam and camera-streamer

Get Help Webcams
1

Hi,
I can not get my old webcam to work.

Camera Model
Bus 001 Device 004: ID 0471:0311 Philips (or NXP) PCVC740K ToUcam Pro [pwc]

Recent, new install of octopi on a RPi3 with the new camera stack.
Edited /boot/camera-streamer/usb-default.conf to have FORMAT=DEFAULT, WIDTH=640, HEIGHT=480, FPS=10

Errors shown:

Jul 22 21:23:02 octopi sh[1248]: device/v4l2/device.c: CAMERA: Device path=/dev/v4l/by-id/usb-0471_0311_RS1000026340000-video>
Jul 22 21:23:02 octopi sh[1248]: device/v4l2/device_options.c: CAMERA: The 'horizontal_flip=0' was failed to find.
Jul 22 21:23:02 octopi sh[1248]: device/v4l2/device_options.c: CAMERA: The 'vertical_flip=0' was failed to find.
Jul 22 21:23:02 octopi sh[1248]: device/camera/camera_input.c: CAMERA: Disabling DMA since device uses USB (which is likely n>
Jul 22 21:23:02 octopi sh[1248]: device/buffer_list.c: CAMERA:capture: Using: 640x480/YU12, buffers=2, bytesperline=640, size>
Jul 22 21:23:02 octopi sh[1248]: device/v4l2/buffer.c: CAMERA:capture: ioctl(ret=-1, errno=25): Can't export queue buffer=0 t>
Jul 22 21:23:02 octopi sh[1248]: device/buffer_list.c: CAMERA:capture: Cannot open buffer: 0

Full log:
https://paste.octoprint.org/us6V0ilgnl

Any ideas?
Thank you and best regards,
Stefan

1 Like
2

Hello @snow-man !

Please upload your logs here - not to (another) file server.

Also, the systeminfo bundle was asked for.

3

Hi,

Sorry that I missed that part:

octoprint-systeminfo-20250723065734.zip (100.9 KB)
octoprint-logs.zip (845.6 KB)

4

Hi Stefan, your old Philips ToUcam (PCVC740K) uses the deprecated pwc driver, which can have compatibility issues with newer V4L2 implementations like OctoPi’s camera-streamer. The key error is ioctl(ret=-1, errno=25), indicating unsupported buffer export (likely due to DMA or format incompatibility). Try editing /boot/camera-streamer/usb-default.conf to set FORMAT=YUYV, which is more widely supported, and reduce FPS to 5. If it still fails, consider switching to the legacy mjpeg-streamer instead of camera-streamer, which tends to work better with older USB webcams.