The driver is built into the kernel. Simply load it:
ffmpeg -f v4l2 -i /dev/video0 -t 10 output.avi Conexant Fusion 878a Driver
Despite being discontinued in 2009, the Fusion 878a has a cult following. like V4L-DVB (Linux) and LibUSB-Win32 wrappers have extended its life. The driver is built into the kernel
The (often seen as the Conexant CX23880 or similar family, or the older Brooktree BT878) is a highly popular video capture chipset from the late 1990s and early 2000s. It was widely used in TV tuner cards, frame grabbers, and analog video capture devices (composite/S-Video). While the hardware was robust for its time, finding and installing a working driver on modern operating systems is a notorious challenge. Conexant Fusion 878a Driver