TV(3) TV(3)
NAME
tv - Hauppage TV device
NAME
bind -b #V /dev
/dev/tv
/dev/tvctl
DESCRIPTION
The tv device serves two files giving access to a Hauppage
television card in NTSC mode (only).
The control device tvctl accepts the following commands to
control tuning and image processing:
init Reset the device to the default settings.
window minx miny maxx maxy
Set the display window size (default: none).
colorkey rl rh gl gh bl bh
Set the key limits for chromakey display to the given
`low' and `high' values for each of red, green and blue
(default: 15 63 255 15 15 63), and enable use of the
colour key. The value 255 for a lower limit disables
the limit.
capture minx miny maxx maxy
Set the capture window (default: none); see the
description of reading the tv file, below.
capbrightness n
Set the brightness of a captured frame to n, on a scale
from 0 to 100 (default: 13).
capcontrast n
Set the contrast of a captured frame to n, on a scale
from 0 to 100 (default: 57).
capsaturation n
Set the saturation of a captured frame to n, on a scale
from 0 to 100 (default: 51).
caphue n
Set the hue of a captured frame to n, on a scale from 0
to 100 (default: 0).
capbw n
Capture colour (n=0) or monochrome (n=1); (default: 0).
Page 1 Plan 9 (printed 12/21/24)
TV(3) TV(3)
brightness n
Set the image brightness to n, on a scale from 0 to 100
(default: 0)
contrast n
Set the image contrast to n, on a scale from 0 to 100
(default: 54)
saturation n
Set image saturation to n, on a scale from 0 to 100
(default: 54)
source n
Set the input source to n (default: video input 0).
svideo n
If n is non-zero, set the input capture format to S-
Video.
format n
Set the input format to n (0, NTSC-M; 1, NTSC-443; 2,
external control). Default: 0.
channel c f
Sets the right frequency for HRC CATV channel c, with
fine tuning by signed offset f (in MHz).
volume m[ n ]
Set the volume of left and right channels to m and n,
on a scale from 0 to 100 (default: 80). If only m is
given, set both left and right volumes to m.
bass n
Set the bass to n, on a scale from 0 to 100 (default:
50).
treble n
Set the treble to n, on a scale from 0 to 100 (default:
50).
freeze n
If n is non-zero, freeze the current frame; if n is
zero, unfreeze the video.
The data file tv is read-only. Reading is valid only after
a capture window has been set (see capture above). Each
read at file offset 0 causes the contents of the input video
image within the previously-set capture window to be cap-
tured. The frame data is successively returned in this and
subsequent reads until a short read signals that all frame
data has been transferred. The data is returned in Plan 9
picfile format, with a two line textual header followed by
Page 2 Plan 9 (printed 12/21/24)
TV(3) TV(3)
an empty line, followed by the image data in binary format.
The header has the form:
TYPE=ccir601
WINDOW=minx miny maxx maxy
The WINDOW coordinates are those of the capture window. The
image data is organised as interleaved scan lines from top
to bottom of the window, with UY0 and VY1 values alternat-
ing, with two bytes per value, stored high-order byte first,
encoded according to the IEEE digital component video stan-
dard.
SOURCE
/os/port/devtv.c
/os/pc/tv.h
SEE ALSO
audio(3)
Page 3 Plan 9 (printed 12/21/24)