--- name: "qvidcap" section: "1" platform: "linux" package: "v4l-utils" version: "1.32.0-2" release: "Arch Linux 2026-11-01" platforms: ["linux"] url: "https://new.carta.tech/qvidcap" --- # qvidcap(1) A v4l2 video capture viewer ## NAME qvidcap - A v4l2 video capture viewer ## SYNOPSIS **qvidcap** \[*\*\] ## 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**=*\* Use device \ as the video device if \ is a number, then /dev/video\ is used - **-f**, **--file**=*\* Read from the file \ for the raw frame data - **-p**, **--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**=*\* Stop after \ captured frames - **-b**, **--buffers**=*\* Request \ buffers (default 4) when streaming from a video device. - **-s**, **--single-step***\[=\\]* Starting with frame \ (default 0), pause after displaying each frame until Space is pressed. - **-C**, **--colorspace**=*\* Override colorspace. \ can be one of the following colorspaces: smpte170m, smpte240m, rec709, 470m, 470bg, jpeg, srgb, oprgb, bt2020, dcip3 - **-X**, **--xfer-func**=*\* Override transfer function. \ can be one of the following transfer functions: default, 709, srgb, oprgb, smpte240m, smpte2084, dcip3, none - **-Y**, **--ycbcr-enc**=*\* Override Y'CbCr encoding. \ can be one of the following Y'CbCr encodings: default, 601, 709, xv601, xv709, bt2020, bt2020c, smpte240m - **-Q**, **--quant**=*\* Override quantization. \ can be one of the following quantization methods: default, full-range, lim-range - **-P**, **--pixelformat**=*\* 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**, **--timing**s 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**=*\* Set width - **-H,--height**=*\* Set frame (not field!) height - **-A,--padding**=*\* set additional horizontal padding (after width) - **--fps**=*\* Set frames-per-second (default is 30) - The following options are only valid when reading from a file: - **-F**, **--field**=*\* Override field setting. \ can be one of the following field layouts: any, none, top, bottom, interlaced, seq\_tb, seq\_bt, alternate, interlaced\_tb, interlaced\_bt - **--no-loop** Stop at the end of the file, don't loop back to the beginning. - **--from-frame**=*\* Start playing back the file at the given frame number (the first frame is frame 0). - The following options are specific to the test pattern generator: - **--list-patterns** List available patterns for use with --pattern - **--pattern**=*\* 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**=*\* Select a pixel aspect ratio, the default is to autodetect. \ can be one of: square, ntsc, pal - **--video-aspect**=*\* Select a video aspect ratio, the default is to use the frame ratio. \ can be one of: 4 x3, 14x9, 16x9, anamorphic - **--alpha**=*\* 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**=*\* Choose speed for horizontal movement, the default is 0 and the range is \[-3...3\] - **--vert-speed**=*\* Choose speed for vertical movement, the default is 0 and the range is \[-3...3\] - **--perc-fill**=*\* Percentage of the frame to actually fill. the default is 100% - These options use the test pattern generator to test the OpenGL backend: - **--test**=*\* Test all formats, each test generates \ frames. - **--test-mask**=*\* Mask which tests are performed. \ 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. When reading from a file, pause playback until the next press of Space. - *Backspace* When single-stepping, go back to the previous 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 \