.TH TVSERVICE 1
.
.SH NAME
tvservice \- get and set information from attached displays
.
.
.SH SYNOPSIS
.SY tvservice
.OP \-a
.OP \-c "mode aspect p"
.OP \-d filename
.OP \-e "group mode drive"
.OP \-j
.OP \-l
.OP \-m group
.OP \-M
.OP \-n
.OP \-o
.OP \-p
.OP \-s
.OP \-t
.OP \-v id
.YS
.
.SY tvservice
.B \-h
.SY tvservice
.B \-\-help
.YS
.
.
.SH DESCRIPTION
.B tvservice
is a command line application used to get and set information about the
display, targeted mainly at HDMI video and audio.
.
Typing
.B tvservice
by itself will display a list of available command line options.
.
.
.SH OPTIONS
.
.TP
.BR \-a ", " \-\-audio
Shows the current settings for the audio mode, including channels, sample rate
and sample size.
.
.TP
.BR \-c ", " \-\-sdtvon " \(dq\fImode aspect \fR[\fIP\fR]\(dq"
Power on the SDTV (composite output) with the specified
.IR mode ,
PAL or NSTC, and the specified
.IR aspect ,
4:3, 14:9, 16:9. The optional \(lqP\(rq parameter can be used to specify
progressive mode. 
.
.TP
.BR \-d ", " \-\-dumpid " \fIfilename\fR"
Save the current EDID to the specified filename. You can then use
.BR edid-decode (1)
to display the data in a human readable form. See
.B [EDID]
for more information on the EDID contents.
.
.TP
.BR \-e ", " \-\-explicit " \(dq\fIgroup mode drive\fR\(dq"
Power on the HDMI display with the specified settings.
.
The
.I group
option can be one of CEA, DMT, CEA_3D_SBS, CEA_3D_TB, CEA_3D_FP, or CEA_3D_FS;
.I mode
is one of the modes returned from the
.B \-\-modes
option. Finally,
.I drive
can be HDMI or DVI. 
.
.TP
.BR \-j ", " \-\-json
When used in combination with the
.B \-\-modes
option, displays the mode information in JSON format. 
.
.TP
.BR \-l ", " \-\-list
Lists all attached displays and their display ID.
.
.TP
.BR \-m ", " \-\-modes " \fIgroup\fR"
Shows a list of display modes available in the specified
.IR group ,
which can be either CEA or DMT.
.
.TP
.BR \-M ", " \-\-monitor
Monitors for any HDMI events, for example unplugging or attaching.
.
.TP
.BR \-n ", " \-\-name
Extracts the display name from the EDID data and shows it.
.
.TP
.BR \-o ", " \-\-off
Powers off the display output.
.IP
.B Important Note:
Powering off the output using this command will also destroy any
framebuffers/dispmanx layers associated with the display. These are NOT
re-established with a subsequent power on, so will result in a blank screen.
.IP
A better option is to use the
.BR vcgencmd (1)
.B display_power
option, as this will retain any framebuffers, so when the power is turned back
on the display will be the returned to the previous power on state.
.
.TP
.BR \-p ", " \-\-preferred
Power on the HDMI output with preferred settings.
.
.TP
.BR \-s ", " \-\-status
Shows the current settings for the display mode, including mode, resolution,
and frequency.
.
.TP
.BR \-t ", " \-\-ntsc
Use 59.94Hz (NTSC frequency) rather than 60Hz for HDMI mode.
.
.TP
.BR \-v ", " \-\-device " \fIid\fR"
Specifies the ID of the device to use; see the output of
.B \-\-list
for available IDs.
.
.
.SH SEE ALSO
.BR vcgencmd (1),
.BR edid-decode (1)
.
.PP
Full documentation at
.BR [SOURCE] .
.
.
.SH REFERENCES
.TP
.B [EDID]
https://en.wikipedia.org/wiki/Extended_Display_Identification_Data
.
.TP
.B [SOURCE]
https://www.raspberrypi.org/documentation/raspbian/applications/tvservice.md