usbvideo.h

一种linux下的看摄像头的画面的软件

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */
#ifndef usbvideo_h
#define	usbvideo_h

#include <linux/config.h>
#include <linux/proc_fs.h>
#include <linux/videodev.h>
#include <linux/usb.h>

/* Most helpful debugging aid */
#define assert(expr) ((void) ((expr) ? 0 : (err("assert failed at line %d",__LINE__))))

#define USES_PROC_FS	(defined(CONFIG_PROC_FS) && defined(CONFIG_VIDEO_PROC_FS))
#define USBVIDEO_REPORT_STATS	1	/* Set to 0 to block statistics on close */

/* Bit flags (options) */
#define FLAGS_RETRY_VIDIOCSYNC		(1 << 0)
#define	FLAGS_MONOCHROME		(1 << 1)
#define FLAGS_DISPLAY_HINTS		(1 << 2)
#define FLAGS_OVERLAY_STATS		(1 << 3)
#define FLAGS_FORCE_TESTPATTERN		(1 << 4)
#define FLAGS_SEPARATE_FRAMES		(1 << 5)
#define FLAGS_CLEAN_FRAMES		(1 << 6)
#define	FLAGS_NO_DECODING		(1 << 7)

/* Bit flags for frames (apply to the frame where they are specified) */
#define USBVIDEO_FRAME_FLAG_SOFTWARE_CONTRAST	(1 << 0)

/* Camera capabilities (maximum) */
#define CAMERA_URB_FRAMES       32
#define CAMERA_MAX_ISO_PACKET   1023 /* 1022 actually sent by camera */
#define FRAMES_PER_DESC		(CAMERA_URB_FRAMES)
#define FRAME_SIZE_PER_DESC	(CAMERA_MAX_ISO_PACKET)

/* This macro restricts an int variable to an inclusive range */
#define RESTRICT_TO_RANGE(v,mi,ma) { if ((v) < (mi)) (v) = (mi); else if ((v) > (ma)) (v) = (ma); }

#define V4L_BYTES_PER_PIXEL     3	/* Because we produce RGB24 */

/*
 * Use this macro to construct constants for different video sizes.
 * We have to deal with different video sizes that have to be
 * configured in the device or compared against when we receive
 * a data. Normally one would define a bunch of VIDEOSIZE_x_by_y
 * #defines and that's the end of story. However this solution
 * does not allow to convert between real pixel sizes and the
 * constant (integer) value that may be used to tag a frame or
 * whatever. The set of macros below constructs videosize constants
 * from the pixel size and allows to reconstruct the pixel size
 * from the combined value later.
 */
#define	VIDEOSIZE(x,y)	(((x) & 0xFFFFL) | (((y) & 0xFFFFL) << 16))
#define	VIDEOSIZE_X(vs)	((vs) & 0xFFFFL)
#define	VIDEOSIZE_Y(vs)	(((vs) >> 16) & 0xFFFFL)
typedef unsigned long videosize_t;

/*
 * This macro checks if the camera is still operational. The 'uvd'
 * pointer must be valid, uvd->dev must be valid, we are not
 * removing the device and the device has not erred on us.
 */
#define CAMERA_IS_OPERATIONAL(uvd) (\
	(uvd != NULL) && \
	((uvd)->dev != NULL) && \
	((uvd)->last_error == 0) && \
	(!(uvd)->remove_pending))

/*
 * We use macros to do YUV -> RGB conversion because this is
 * very important for speed and totally unimportant for size.
 *
 * YUV -> RGB Conversion
 * ---------------------
 *
 * B = 1.164*(Y-16)		    + 2.018*(V-128)
 * G = 1.164*(Y-16) - 0.813*(U-128) - 0.391*(V-128)
 * R = 1.164*(Y-16) + 1.596*(U-128)
 *
 * If you fancy integer arithmetics (as you should), hear this:
 *
 * 65536*B = 76284*(Y-16)		  + 132252*(V-128)
 * 65536*G = 76284*(Y-16) -  53281*(U-128) -  25625*(V-128)
 * 65536*R = 76284*(Y-16) + 104595*(U-128)
 *
 * Make sure the output values are within [0..255] range.
 */
#define LIMIT_RGB(x) (((x) < 0) ? 0 : (((x) > 255) ? 255 : (x)))
#define YUV_TO_RGB_BY_THE_BOOK(my,mu,mv,mr,mg,mb) { \
    int mm_y, mm_yc, mm_u, mm_v, mm_r, mm_g, mm_b; \
    mm_y = (my) - 16;  \
    mm_u = (mu) - 128; \
    mm_v = (mv) - 128; \
    mm_yc= mm_y * 76284; \
    mm_b = (mm_yc		+ 132252*mm_v	) >> 16; \
    mm_g = (mm_yc -  53281*mm_u -  25625*mm_v	) >> 16; \
    mm_r = (mm_yc + 104595*mm_u			) >> 16; \
    mb = LIMIT_RGB(mm_b); \
    mg = LIMIT_RGB(mm_g); \
    mr = LIMIT_RGB(mm_r); \
}

#define	RING_QUEUE_SIZE		(128*1024)	/* Must be a power of 2 */
#define	RING_QUEUE_ADVANCE_INDEX(rq,ind,n) (rq)->ind = ((rq)->ind + (n)) & ((rq)->length-1)
#define	RING_QUEUE_DEQUEUE_BYTES(rq,n) RING_QUEUE_ADVANCE_INDEX(rq,ri,n)
#define	RING_QUEUE_PEEK(rq,ofs) ((rq)->queue[((ofs) + (rq)->ri) & ((rq)->length-1)])

struct RingQueue {
	unsigned char *queue;	/* Data from the Isoc data pump */
	int length;		/* How many bytes allocated for the queue */
	int wi;			/* That's where we write */
	int ri;			/* Read from here until you hit write index */
	wait_queue_head_t wqh;	/* Processes waiting */
};

enum ScanState {
	ScanState_Scanning,	/* Scanning for header */
	ScanState_Lines		/* Parsing lines */
};

/* Completion states of the data parser */
enum ParseState {
	scan_Continue,		/* Just parse next item */
	scan_NextFrame,		/* Frame done, send it to V4L */
	scan_Out,		/* Not enough data for frame */
	scan_EndParse		/* End parsing */
};

enum FrameState {
	FrameState_Unused,	/* Unused (no MCAPTURE) */
	FrameState_Ready,	/* Ready to start grabbing */
	FrameState_Grabbing,	/* In the process of being grabbed into */
	FrameState_Done,	/* Finished grabbing, but not been synced yet */
	FrameState_Done_Hold,	/* Are syncing or reading */
	FrameState_Error,	/* Something bad happened while processing */
};

/*
 * Some frames may contain only even or odd lines. This type
 * specifies what type of deinterlacing is required.
 */
enum Deinterlace {
	Deinterlace_None=0,
	Deinterlace_FillOddLines,
	Deinterlace_FillEvenLines
};

#define USBVIDEO_NUMFRAMES	2	/* How many frames we work with */
#define USBVIDEO_NUMSBUF	2	/* How many URBs linked in a ring */

/* This structure represents one Isoc request - URB and buffer */
struct usbvideo_sbuf {
	char *data;
	struct urb *urb;
};

struct usbvideo_frame {
	char *data;		/* Frame buffer */
	unsigned long header;	/* Significant bits from the header */

	videosize_t canvas;	/* The canvas (max. image) allocated */
	videosize_t request;	/* That's what the application asked for */
	unsigned short palette;	/* The desired format */

	enum FrameState frameState;/* State of grabbing */
	enum ScanState scanstate;	/* State of scanning */
	enum Deinterlace deinterlace;
	int flags;		/* USBVIDEO_FRAME_FLAG_xxx bit flags */

	int curline;		/* Line of frame we're working on */

	long seqRead_Length;	/* Raw data length of frame */
	long seqRead_Index;	/* Amount of data that has been already read */

	void *user;		/* Additional data that user may need */
};

/* Statistics that can be overlaid on screen */
struct usbvideo_statistics {
        unsigned long frame_num;	/* Sequential number of the frame */
        unsigned long urb_count;        /* How many URBs we received so far */
        unsigned long urb_length;       /* Length of last URB */
        unsigned long data_count;       /* How many bytes we received */
        unsigned long header_count;     /* How many frame headers we found */
	unsigned long iso_skip_count;	/* How many empty ISO packets received */
	unsigned long iso_err_count;	/* How many bad ISO packets received */
};

struct usbvideo;

struct uvd {
	struct video_device vdev;	/* Must be the first field! */
	struct usb_device *dev;
	struct usbvideo *handle;	/* Points back to the struct usbvideo */
	void *user_data;		/* Camera-dependent data */
	int user_size;			/* Size of that camera-dependent data */
	int debug;			/* Debug level for usbvideo */
	unsigned char iface;		/* Video interface number */
	unsigned char video_endp;
	unsigned char ifaceAltActive;