qvidcap - Man Page

A v4l2 video capture viewer

Synopsis

qvidcap [<options>]

Description

The qvidcap tool is used to test video4linux capture devices, either using a video device, a file, or over network. This application can also serve as a generic video/TV viewer application.

It does not (yet) support compressed video streams other than MJPEG

Options

-d,  --device=<dev>

Use device <dev> as the video device if <dev> is a number, then /dev/video<dev> is used

-f,  --file=<file>

Read from the file <file> for the raw frame data

-p,  --port[=<port>]

Listen for a network connection on the given port. The default port is 8362

-T,  --tpg

Use the test pattern generator. If neither -d, -f nor -T is specified then use /dev/video0.

-c,  --count=<cnt>

Stop after <cnt> captured frames

-b,  --buffers=<bufs>

Request <bufs> buffers (default 4) when streaming from a video device.

-s,  --single-step[=<frm>]

Starting with frame <frm> (default 1), pause after displaying each frame until Space is pressed.

-C,  --colorspace=<c>

Override colorspace. <c> can be one of the following colorspaces: smpte170m, smpte240m, rec709, 470m, 470bg, jpeg, srgb, oprgb, bt2020, dcip3

-X,  --xfer-func=<x>

Override transfer function. <x> can be one of the following transfer functions: default, 709, srgb, oprgb, smpte240m, smpte2084, dcip3, none

-Y,  --ycbcr-enc=<y>

Override Y'CbCr encoding. <y> can be one of the following Y'CbCr encodings: default, 601, 709, xv601, xv709, bt2020, bt2020c, smpte240m

-Q,  --quant=<q>

Override quantization. <q> can be one of the following quantization methods: default, full-range, lim-range

-P,  --pixelformat=<p>

For video devices: set the format to this pixel format. For reading from a file: interpret the data using this pixel format setting. Ignored for other modes. Use -l to see the list of supported pixel formats.

-l,  --list-formats

Display all supported formats

-h,  --help

Display this help message

-t,  --timings

Report frame render timings

-v,  --verbose

Be more verbose

-R,  --raw

Open device in raw mode

--opengl

Force openGL to display the video

--opengles

Force openGL ES to display the video

The following options are ignored when capturing from a video device:
-W,--width=<width>

Set width

-H,--height=<height>

Set frame (not field!) height

-A,--padding=<bytes>

set additional horizontal padding (after width)

--fps=<fps>

Set frames-per-second (default is 30)

The following option is only valid when reading from a file:
-F,  --field=<f>

Override field setting. <f> can be one of the following field layouts: any, none, top, bottom, interlaced, seq_tb, seq_bt, alternate, interlaced_tb, interlaced_bt

The following options are specific to the test pattern generator:
--list-patterns

List available patterns for use with --pattern

--pattern=<pat>

Choose output test pattern, the default is 0

--square

Show a square in the middle of the output test pattern

--border

Show a border around the pillar/letterboxed video

--sav

Insert an SAV code in every line

--eav

Insert an EAV code in every line

--pixel-aspect=<aspect>

Select a pixel aspect ratio, the default is to autodetect. <aspect> can be one of: square, ntsc, pal

--video-aspect=<aspect>

Select a video aspect ratio, the default is to use the frame ratio. <aspect> can be one of: 4  x3, 14x9, 16x9, anamorphic

--alpha=<alpha-value>

Value to use for the alpha component, range 0-255, the default is 0

--alpha-red-only

Only use the --alpha value for the red colors, for all others use 0

--rgb-lim-range

Encode RGB values as limited [16-235] instead of full range

--hor-speed=<speed>

Choose speed for horizontal movement, the default is 0 and the range is [-3...3]

--vert-speed=<speed>

Choose speed for vertical movement, the default is 0 and the range is [-3...3]

--perc-fill=<percentage>

Percentage of the frame to actually fill. the default is 100%

These options use the test pattern generator to test the OpenGL backend:
--test=<count>

Test all formats, each test generates <count> frames.

--test-mask=<mask>

Mask which tests are performed. <mask> is a bit mask with these values:
0x01: Mask iterating over pixel formats
0x02: Mask iterating over fields
0x04: Mask iterating over colorspaces
0x08: Mask iterating over transfer functions
0x10: Mask iterating over Y'CbCr encodings
0x20: Mask iterating over quantization ranges

Hotkeys

Q

Quit application.

P

Cycle forwards through all the supported pixel formats. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original pixel format. Only available with --file.

I

Cycle forwards through all the supported interlaced field settings. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original interlaced field setting. Only available with --file.

C

Cycle forwards through all the supported colorspaces. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original colorspace.

X

Cycle forwards through all the supported transfer functions. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original transfer function.

Y

Cycle forwards through all the supported Y'CbCr encodings. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original Y'CbCr encoding.

H

Cycle forwards through all the supported HSV encodings. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original HSV encoding.

R

Cycle forwards through all the supported quantization ranges. With Shift pressed: cycle backwards. With Ctrl pressed: restore the original quantization range.

Right-Click

Open menu.

Double left-click

Toggle fullscreen on and off.

F

Toggle fullscreen on and off.

ESC

Exit fullscreen.

Space

When in test mode (--test) pressing Space will skip to the next test. When single-stepping, continue to the next frame.

Up

Reduce the resolution by two pixels in height. Only available when "Override resolution" is enabled.

Down

Increase the resolution by two pixels in height. Only available when "Override resolution" is enabled.

Left

Reduce the resolution by two pixels in width. Only available when "Override resolution" is enabled.

Right

Increase the resolution by two pixels in width. Only available when "Override resolution" is enabled.

Exit Status

On success, it returns 0. Otherwise, it will return the number of errors.

Bugs

Report bugs to Hans Verkuil <hverkuil@xs4all.nl>

Info

June 2016 v4l-utils 1.20.0