Query: dv4lstart
OS: debian
Section: 1
Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar
DV4LSTART(1) General Commands Manual DV4LSTART(1)NAMEdv4lstart - redirect V4L API to access a camcorder from a V4L programSYNOPSISdvlstart [options] command [argument ...]DESCRIPTIONdv4lstart enables command to access a dv1394 (Firewire) camcorder by using the video4linux (V4L) API. dv4lstart uses the LD_PRELOAD facil- ity to intercept calls to the V4L API and make the camcorder's videostream available. Check that LD_PRELOAD works in your environment by starting $ dv4lstart ls -l /dev/video0 The resulting output should look like crw-rw---- 0 root video 81, 0 Jan 1 1970 /dev/video0 Check your 1394 driver config by starting $ gst-launch-0.10 dv1394src ! dvdemux ! dvdec ! xvimagesink from your shell. After turning on your camera, a video window should appear. If this works, dv4lstart should work as well. Inside command, use /dev/video0. Any existing, real V4L device named /dev/video0 can not be accessed from an application started with dv4lstart (applications started normally can access the real /dev/video0)OPTIONS-c, --color-correction Set this option if red objects look blue. -n, --new-dev Tell dv4lstart to simulate a new video device rather than overriding /dev/video0. Set this option if your application needs to access other video devices. -r, --rgb-only Set this option to prevent V4L applications from choosing YUV palettes. Try this option if you get low frame rates. -v, --verbose level Set the amount of debugging messages. A level of 0 means no output at all, 1 is the default, 3 enables all messages. -h, --help displays a help messageEXAMPLESThe command $ dv4lstart v4l-info outputs some information about the simulated V4L device. $ dv4lstart -c gqcam -v /dev/video0 starts the gqcam webcam viewer, swapping red and blue colors.LIMITATIONSPrograms using exotic ways to access the V4L API will not work. Some environments don't allow the use of LD_PRELOAD for security reasons. dv4lstart will not work there. If dv4lstart does not work, try dv4l instead.SEE ALSOdv4l(1) DV4LSTART(1)