Interfacing webcam with NetBSD

[Mayuresh <mayuresh%acm.org@localhost>]

My system is:
NetBSD asusnetbsd 8.0_RC1 NetBSD 8.0_RC1 (GENERIC.201804191727Z) amd64 x86_64 Intel 686-class NetBSD

Following dmesg messages occur on plugging the webcam to USB port:

uvideo1 at uhub4 port 2 configuration 1 interface 0: ARKMICRO (0x18ec) USB2.0 PC CAMERA (0x3399), rev 2.00/1.00, addr 24
video1 at uvideo1: ARKMICRO (0x18ec) USB2.0 PC CAMERA (0x3399), rev 2.00/1.00, addr 24
uaudio0 at uhub4 port 2 configuration 1 interface 2
uaudio0: ARKMICRO (0x18ec) USB2.0 PC CAMERA (0x3399), rev 2.00/1.00, addr 24
uaudio0: audio rev 1.00 audio2 at uaudio0: full duplex, playback, capture, mmap, independent
uaudio0: Virtual format configured - Format SLINEAR, precision 16, channels 2, frequency 48000
uaudio0: Latency: 180 milliseconds
spkr3 at audio2: PC Speaker (synthesized)

At present I just want to play the camera output on x11 screen. So far,
with mplayer (tried with v4l2 driver and various of its options) managed
to show only a green screen. ffmpeg4, mpv gave input/output error.

Device permissions /dev/video* are set right manually to be owned by a non root user.

What could be the options to get this work - either applications or even
APIs would do?

Mayuresh