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/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
/*
* v4l2loopback.h
*
* Written by IOhannes m zmölnig, 7/1/20.
*
* Copyright 2020 by IOhannes m zmölnig. Redistribution of this file is
* permitted under the GNU General Public License.
*/
#ifndef _V4L2LOOPBACK_H
#define _V4L2LOOPBACK_H
#define V4L2LOOPBACK_VERSION_MAJOR 0
#define V4L2LOOPBACK_VERSION_MINOR 15
#define V4L2LOOPBACK_VERSION_BUGFIX 0
/* /dev/v4l2loopback interface */
struct v4l2_loopback_config {
/**
* the device-number (/dev/video<nr>)
* V4L2LOOPBACK_CTL_ADD:
* setting this to a value<0, will allocate an available one
* if nr>=0 and the device already exists, the ioctl will EEXIST
* if output_nr and capture_nr are the same, only a single device will be created
* NOTE: currently split-devices (where output_nr and capture_nr differ)
* are not implemented yet.
* until then, requesting different device-IDs will result in EINVAL.
*
* V4L2LOOPBACK_CTL_QUERY:
* either both output_nr and capture_nr must refer to the same loopback,
* or one (and only one) of them must be -1
*
*/
__s32 output_nr;
__s32 unused; /*capture_nr;*/
/**
* a nice name for your device
* if (*card_label)==0, an automatic name is assigned
*/
char card_label[32];
/**
* allowed frame size
* if too low, default values are used
*/
__u32 min_width;
__u32 max_width;
__u32 min_height;
__u32 max_height;
/**
* number of buffers to allocate for the queue
* if set to <=0, default values are used
*/
__s32 max_buffers;
/**
* how many consumers are allowed to open this device concurrently
* if set to <=0, default values are used
*/
__s32 max_openers;
/**
* set the debugging level for this device
*/
__s32 debug;
/**
* whether to announce OUTPUT/CAPTURE capabilities exclusively
* for this device or not
* (!exclusive_caps)
* NOTE: this is going to be removed once separate output/capture
* devices are implemented
*/
__s32 announce_all_caps;
};
#define V4L2LOOPBACK_CTL_IOCTLMAGIC '~'
/* a pointer to an (unsigned int) that - on success - will hold
* the version code of the v4l2loopback module
* as returned by KERNEL_VERSION(MAJOR, MINOR, BUGFIX)
*/
#define V4L2LOOPBACK_CTL_VERSION _IOR(V4L2LOOPBACK_CTL_IOCTLMAGIC, 0, __u32)
/* a pointer to a (struct v4l2_loopback_config) that has all values you wish to impose on the
* to-be-created device set.
* if the ptr is NULL, a new device is created with default values at the driver's discretion.
*
* returns the device_nr of the OUTPUT device (which can be used with V4L2LOOPBACK_CTL_QUERY,
* to get more information on the device)
*/
#define V4L2LOOPBACK_CTL_ADD \
_IOW(V4L2LOOPBACK_CTL_IOCTLMAGIC, 1, struct v4l2_loopback_config)
/* the device-number (either CAPTURE or OUTPUT) associated with the loopback-device */
#define V4L2LOOPBACK_CTL_REMOVE _IOW(V4L2LOOPBACK_CTL_IOCTLMAGIC, 2, __u32)
/* a pointer to a (struct v4l2_loopback_config) that has output_nr and/or capture_nr set
* (the two values must either refer to video-devices associated with the same loopback device
* or exactly one of them must be <0
*/
#define V4L2LOOPBACK_CTL_QUERY \
_IOWR(V4L2LOOPBACK_CTL_IOCTLMAGIC, 3, struct v4l2_loopback_config)
#endif /* _V4L2LOOPBACK_H */
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