sc_v4l2.h File Reference

Support for video for linux version 2. More...

#include <sc.h>

Include dependency graph for sc_v4l2.h:

Go to the source code of this file.

Typedefs
typedef struct sc_v4l2_device	sc_v4l2_device_t
	Opaque structure for a video device.

Functions
sc_v4l2_device_t *	sc_v4l2_device_open (const char *devname)
	Open a video device by special file name. More...
int	sc_v4l2_device_close (sc_v4l2_device_t *vd)
	Close a video device. More...
const char *	sc_v4l2_device_devstring (const sc_v4l2_device_t *vd)
	Return string that details some driver and device properties. More...
const char *	sc_v4l2_device_capstring (const sc_v4l2_device_t *vd)
	Return string that details some device capabilities. More...
const char *	sc_v4l2_device_outstring (const sc_v4l2_device_t *vd)
	Return string that details some output properties. More...
int	sc_v4l2_device_is_readwrite (const sc_v4l2_device_t *vd)
	Query whether a device supports read/write I/O. More...
int	sc_v4l2_device_is_streaming (const sc_v4l2_device_t *vd)
	Query whether a device supports streaming I/O. More...
int	sc_v4l2_device_select (sc_v4l2_device_t *vd, unsigned usec)
	Call select (2) to wait for write availability of device. More...
int	sc_v4l2_device_write (sc_v4l2_device_t *vd, const char *wbuf)
	Call write (2) to copy an image buffer to device. More...
int	sc_v4l2_device_format (sc_v4l2_device_t *vd, unsigned int *width, unsigned int *height, unsigned int *bytesperline, unsigned int *sizeimage)
	Set output configuration of device. More...

Detailed Description

Support for video for linux version 2.

Function Documentation

sc_v4l2_device_capstring()

const char* sc_v4l2_device_capstring

(

const sc_v4l2_device_t *

vd

)

Return string that details some device capabilities.

Parameters

[in]

vd

Opened sc_v4l2_device_t. Not modified.

Returns

NUL-terminated string only valid while the device vd is.

sc_v4l2_device_close()

int sc_v4l2_device_close

(

sc_v4l2_device_t *

vd

)

Close a video device.

Parameters

[in,out]

vd

Close this device and deallocate associated resources.

Returns

0 on success, -1 otherwise.

sc_v4l2_device_devstring()

const char* sc_v4l2_device_devstring

(

const sc_v4l2_device_t *

vd

)

Return string that details some driver and device properties.

Parameters

[in]

vd

Opened sc_v4l2_device_t. Not modified.

Returns

NUL-terminated string only valid while the device vd is.

sc_v4l2_device_format()

int sc_v4l2_device_format	(	sc_v4l2_device_t *	vd,
		unsigned int *	width,
		unsigned int *	height,
		unsigned int *	bytesperline,
		unsigned int *	sizeimage
	)

Set output configuration of device.

We demand sRGB color space with RGB 565 pixel format (2 bytes). The image size values on output define the buffer size to allocate.

Parameters

[in,out]	vd	Device must support the desired output format.
[in,out]	width	Desired width on input, actual width on output.
[in,out]	height	Desired height on input, actual height on output.
[out]	bytesperline	Bytes per line on output, including padding.
[out]	sizeimage	Bytes per image, including padding.

Returns

0 on success, -1 otherwise and setting errno.

sc_v4l2_device_is_readwrite()

int sc_v4l2_device_is_readwrite

(

const sc_v4l2_device_t *

vd

)

Query whether a device supports read/write I/O.

Parameters

[in]

vd

Any pointer.

Returns

True iff vd is valid and read/write is supported.

sc_v4l2_device_is_streaming()

int sc_v4l2_device_is_streaming

(

const sc_v4l2_device_t *

vd

)

Query whether a device supports streaming I/O.

Parameters

[in]

vd

Any pointer.

Returns

True iff vd is valid and streaming is supported.

sc_v4l2_device_open()

sc_v4l2_device_t* sc_v4l2_device_open

(

const char *

devname

)

Open a video device by special file name.

The device is queried but its state is not modified.

Parameters

[in]

devname

Special file name such as /dev/video8.

Returns

Valid pointer on success, NULL on error.

sc_v4l2_device_outstring()

const char* sc_v4l2_device_outstring

(

const sc_v4l2_device_t *

vd

)

Return string that details some output properties.

Parameters

[in]

vd

Opened sc_v4l2_device_t. Not modified.

Returns

If output is supported as desired, return NUL-terminated string only valid while the vd object is alive. Otherwise return NULL.

sc_v4l2_device_select()

int sc_v4l2_device_select	(	sc_v4l2_device_t *	vd,
		unsigned	usec
	)

Call select (2) to wait for write availability of device.

Parameters

[in]	vd	Opened sc_v4l2_device_t capable of output.
[in]	usec	Number of microseconds to wait for device. We return sooner if interrupted by a signal.

Returns

-1 on error, 0 on timeout, 1 when ready for writing.

sc_v4l2_device_write()

int sc_v4l2_device_write	(	sc_v4l2_device_t *	vd,
		const char *	wbuf
	)

Call write (2) to copy an image buffer to device.

Parameters

[in]	vd	Opened sc_v4l2_device_t capable of output.
[in]	wbuf	Buffer holding at least sizeimage many bytes.

Returns

0 on success, -1 otherwise and setting errno.