/* * vidcat.c * * Copyright (C) 1998 - 2001 Rasca, Berlin * * 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 of the License, 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. */#include <stdio.h>#include <stdlib.h>#include <string.h>#include <getopt.h>#include <sys/types.h>#include <sys/stat.h>#include <sys/ioctl.h>#include <sys/mman.h>#include <sys/time.h>	/* gettimeofday() */#include <fcntl.h>#include <unistd.h>#include <linux/types.h>#include <linux/videodev.h>#ifdef HAVE_LIBZ#include <zlib.h>#endif#ifdef HAVE_LIBPNG#include <png.h>#endif#ifdef HAVE_LIBJPEG#include <jpeglib.h>#endif#include "v4l.h"#define DEF_WIDTH	320	/* default width */#define DEF_HEIGHT	240	/* default height */#define FMT_UNKNOWN		0#define FMT_PPM			1#define FMT_PGM			2#define FMT_PNG			3#define FMT_JPEG		4#define FMT_YUV4MPEG	5#define IN_TV			0#define IN_COMPOSITE	1#define IN_COMPOSITE2	2#define IN_SVIDEO		3#define NORM_PAL		0#define NORM_NTSC		1#define NORM_SECAM		2#define QUAL_DEFAULT	80char *basename (const char *s);/* globals */static int verbose = 0;/* */voidusage (char *pname){	fprintf (stderr,	"VidCat, Version %s\n"	"Usage: %s <options>\n"	" -b                          make a raw PPM instead of an ASCII one\n"	" -d <device>                 video device (default: "VIDEO_DEV")\n"	" -f {ppm|jpeg|png|yuv4mpeg}  output format of the image\n"	" -g                          greayscale instead of color\n"	" -i {tv|comp1|comp2|s-video} which input channel to use\n"	" -l                          loop on, doesn't make sense in most cases\n"	" -n {pal|ntsc|secam}         select video norm\n"	" -o <file>                   write output to file instead of stdout\n"	" -p c|g|y|Y                  videopalette to use\n"	" -q <quality>                only for jpeg: quality setting (1-100,"		" default: %d)\n"	" -s NxN                      define size of the output image (default:"		" %dx%d)\n"	"Example: vidcat | xsetbg stdin\n",		VERSION, (char*)basename(pname), QUAL_DEFAULT, DEF_WIDTH, DEF_HEIGHT);	exit (1);}/* */doublems_time (void){	static struct timeval tod;	gettimeofday (&tod, NULL);	return ((double)tod.tv_sec * 1000.0 + (double)tod.tv_usec / 1000.0);	}/* * read rgb image from v4l device 從v4l設(shè)備獲取rgb圖像 * return: mmap'ed buffer and size */char *get_image (int dev, int width, int height, int palette ,int *size){	struct video_mbuf vid_buf;	struct video_mmap vid_mmap;	char *map, *convmap; //map指向抓到的圖片所存空間	int len; 	int bytes = 3;  //比特每像素	if (palette == VIDEO_PALETTE_GREY) //若為灰度圖象		bytes = 1;	/* bytes per pixel */	if (ioctl (dev, VIDIOCGMBUF, &vid_buf) == -1) {		/* to do a normal read()		 */		struct video_window vid_win;		if (verbose) {			fprintf (stderr, "using read()\n");		}		if (ioctl (dev, VIDIOCGWIN, &vid_win) != -1) {			vid_win.width  = width;			vid_win.height = height;			if (ioctl (dev, VIDIOCSWIN, &vid_win) == -1) {				perror ("ioctl(VIDIOCSWIN)");  //ioctl函數(shù)功能？？				return (NULL);			}		}		map = malloc (width * height * bytes); //分配空間		len = read (dev, map, width * height * bytes); //從v41設(shè)備讀取圖像信息到map所指向的空間		if (len <=  0) {			free (map);			return (NULL);		}		*size = 0;		if (palette == VIDEO_PALETTE_YUV420P) {			convmap = malloc ( width * height * bytes );			v4l_yuv420p2rgb (convmap, map, width, height, bytes * 8);//顏色空間的轉(zhuǎn)換 			memcpy (map, convmap, (size_t) width * height * bytes); //將convmap指向的圖像的值復(fù)制 
			                                                      //到map指向的一段連續(xù)的空間			free (convmap);		} else if (palette == VIDEO_PALETTE_YUV422P) {			convmap = malloc ( width * height * bytes );			v4l_yuv422p2rgb (convmap, map, width, height, bytes * 8);			memcpy (map, convmap, (size_t) width * height * bytes);			free (convmap);		}		return (map);  //返回map，map指向抓到的圖像信息所存放的位置	}
	map = mmap (0, vid_buf.size, PROT_READ|PROT_WRITE,MAP_SHARED,dev,0); //？？	if ((unsigned char *)-1 == (unsigned char *)map) {		perror ("mmap()");		return (NULL);	}	vid_mmap.format = palette;	vid_mmap.frame = 0;	vid_mmap.width = width;	vid_mmap.height = height;	if (ioctl (dev, VIDIOCMCAPTURE, &vid_mmap) == -1) {		perror ("VIDIOCMCAPTURE");		fprintf (stderr, "args: width=%d height=%d palette=%d\n",					vid_mmap.width, vid_mmap.height, vid_mmap.format);		munmap (map, vid_buf.size);		return (NULL);	}	if (ioctl (dev, VIDIOCSYNC, &vid_mmap.frame) == -1) {		perror ("VIDIOCSYNC");		munmap (map, vid_buf.size);		return (NULL);	}	*size = vid_buf.size;		if (palette == VIDEO_PALETTE_YUV420P) {		if (verbose)			fprintf (stderr, "converting from YUV to RGB\n");		convmap = malloc ( width * height * bytes );		v4l_yuv420p2rgb (convmap, map, width, height, bytes * 8);		memcpy (map, convmap, (size_t) width * height * bytes);		free (convmap);	} else if (palette == VIDEO_PALETTE_YUV422P) {		if (verbose)			fprintf (stderr, "converting from YUV to RGB\n");		convmap = malloc ( width * height * bytes );		v4l_yuv422p2rgb (convmap, map, width, height, bytes * 8);		memcpy (map, convmap, (size_t) width * height * bytes);		free (convmap);	}		return (map);	if (verbose)		fprintf (stderr, "got picture\n");}/*將get_image函數(shù)抓到的圖片壓縮成不同的格式 */voidput_image_jpeg (FILE *out, char *image, int width, int height, int quality, int palette){#ifdef HAVE_LIBJPEG	int y, x, line_width;	JSAMPROW row_ptr[1];	struct jpeg_compress_struct cjpeg;	struct jpeg_error_mgr jerr;	char *line;	line = malloc (width * 3);	if (!line)		return;	if (verbose)		fprintf (stderr, "writing JPEG data\n");	cjpeg.err = jpeg_std_error(&jerr);	jpeg_create_compress (&cjpeg); //創(chuàng)建jpge壓縮結(jié)構(gòu)體	cjpeg.image_width = width;	cjpeg.image_height= height;	if (palette == VIDEO_PALETTE_GREY) {		cjpeg.input_components = 1;  //若為灰度圖象，每像素一個bit		cjpeg.in_color_space = JCS_GRAYSCALE;	//	jpeg_set_colorspace (&cjpeg, JCS_GRAYSCALE);	} else {		cjpeg.input_components = 3;  //若不是灰度圖象，每像素3個bit		cjpeg.in_color_space = JCS_RGB; //rgb的顏色空間	}	jpeg_set_defaults (&cjpeg);	jpeg_set_quality (&cjpeg, quality, TRUE);	cjpeg.dct_method = JDCT_FASTEST;	jpeg_stdio_dest (&cjpeg, out);	jpeg_start_compress (&cjpeg, TRUE);	row_ptr[0] = line;	if (palette == VIDEO_PALETTE_GREY) {		line_width = width;		for ( y = 0; y < height; y++) {			row_ptr[0] = image;			jpeg_write_scanlines (&cjpeg, row_ptr, 1);			image += line_width;		}	} else {		line_width = width * 3;		for ( y = 0; y < height; y++) {			for (x = 0; x < line_width; x+=3) {				line[x]   = image[x+2];				line[x+1] = image[x+1];				line[x+2] = image[x];			}			jpeg_write_scanlines (&cjpeg, row_ptr, 1);			image += line_width;		}	}	jpeg_finish_compress (&cjpeg);	jpeg_destroy_compress (&cjpeg);	free (line);#endif}/* * write png image to stdout */voidput_image_png (FILE *out, char *image, int width, int height, int palette){#ifdef HAVE_LIBPNG	int y, bpp;	char *p;	png_infop info_ptr;	png_structp png_ptr = png_create_write_struct (PNG_LIBPNG_VER_STRING,						NULL, NULL, NULL);	if (!png_ptr)		return;	info_ptr = png_create_info_struct (png_ptr);	if (!info_ptr)		return;	png_init_io (png_ptr, out);	if (palette == VIDEO_PALETTE_GREY) {		png_set_IHDR (png_ptr, info_ptr, width, height,					8, PNG_COLOR_TYPE_GRAY, PNG_INTERLACE_NONE,					PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);		bpp = 1;	} else {		png_set_IHDR (png_ptr, info_ptr, width, height,					8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE,					PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);		bpp = 3;	}	png_set_bgr (png_ptr);	png_write_info (png_ptr, info_ptr);	p = image;	for (y = 0; y < height; y++) {		png_write_row (png_ptr, p);		p += width * bpp;	}	png_write_end (png_ptr, info_ptr);#endif}/* * write ppm image to stdout / file */voidput_image_ppm (FILE *out, char *image, int width, int height, int binary){	int x, y, ls=0;	unsigned char *p = (unsigned char *)image;	if (!binary) {		fprintf (out, "P3\n%d %d\n%d\n", width, height, 255);		for (x = 0; x < width; x++) {			for (y = 0; y < height; y++) {				fprintf (out, "%03d %03d %03d  ", p[2], p[1], p[0]);				p += 3;				if (ls++ > 4) {					fprintf (out, "\n");					ls = 0;				}			}		}		fprintf (out, "\n");