#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h> #include <getopt.h> /* getopt_long() */ #include <fcntl.h> /* low-level i/o */
#include <unistd.h>
#include <errno.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h> #include <linux/videodev2.h> #define FORCED_WIDTH 640
#define FORCED_HEIGHT 480
#define FORCED_FORMAT V4L2_PIX_FMT_YUYV
#define FORCED_FIELD V4L2_FIELD_ANY static int verbose = ;
#define pr_debug(fmt, arg...) \
if (verbose) fprintf(stderr, fmt, ##arg) #define CLEAR(x) memset(&(x), 0, sizeof(x)) //相当于CLEAR(x) =memset(&(x), 0, sizeof(x)) enum io_method { //枚举,即只能取其中的一个值。也是一种数据结构
IO_METHOD_READ,
IO_METHOD_MMAP,
IO_METHOD_USERPTR,
}; struct buffer {
void *start;
size_t length; //size_t =unsigned int 用来表示sizeof的
}; static char *dev_name; //用来保存设备名
static enum io_method io = IO_METHOD_MMAP;
static int fd = -;
struct buffer *buffers;
static unsigned int n_buffers;
static int out_buf;
static int force_format;
static int frame_count = ;
static char *video_name="video.yuv";
FILE *fp; //保存视频 static void errno_exit(const char *s)
{
fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno));
exit(EXIT_FAILURE);
} static int xioctl(int fh, int request, void *arg)
{
int r; do {
r = ioctl(fh, request, arg);
} while (- == r && EINTR == errno); return r;
} static void process_image(const void *p, int size)
{
pr_debug("%s: called!\n", __func__);
//采集视频
fwrite(p,size,,fp);//如果要查看采集视频的格式,在linux下可以通过安装v4l-utils,然后执行v4l2-ctl --all来查看视频采集的相关信息
// 保存为一张张图片
/* FILE *fp;
static int num = 1;
char picture_name[20]; sprintf(picture_name,"picture%d.jpg",num ++); if((fp = fopen(picture_name,"w")) == NULL)
{
perror("Fail to fopen");
exit(EXIT_FAILURE);
} fwrite(p,size,1,fp);
usleep(500); fclose(fp);
*/ // 打印到标准输出
/*if (out_buf)
fwrite(p, size, 1, stdout); fflush(stderr);
fprintf(stderr, ".");
fflush(stdout);
*/ } static int read_frame(void)
{
struct v4l2_buffer buf;
unsigned int i; pr_debug("%s: called!\n", __func__); switch (io) {
case IO_METHOD_READ: break; case IO_METHOD_MMAP:
CLEAR(buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP; if (- == xioctl(fd, VIDIOC_DQBUF, &buf)) {
switch (errno) {
case EAGAIN:
return ; case EIO:
/* Could ignore EIO, see spec. */ /* fall through */ default:
errno_exit("VIDIOC_DQBUF");
}
} assert(buf.index < n_buffers); process_image(buffers[buf.index].start, buf.bytesused); if (- == xioctl(fd, VIDIOC_QBUF, &buf))
errno_exit("VIDIOC_QBUF");
break; case IO_METHOD_USERPTR: break;
} return ;
} static void mainloop(void)
{
unsigned int count; pr_debug("%s: called!\n", __func__); count = frame_count; while (count-- > ) {
for (;;) {
fd_set fds;
struct timeval tv;
int r; FD_ZERO(&fds);
FD_SET(fd, &fds); /* Timeout. */
tv.tv_sec = ;
tv.tv_usec = ; r = select(fd + , &fds, NULL, NULL, &tv); if (- == r) {
if (EINTR == errno)
continue;
errno_exit("select");
} if ( == r) {
fprintf(stderr, "select timeout\n");
exit(EXIT_FAILURE);
} if (read_frame())
break;
/* EAGAIN - continue select loop. */
}
}
} static void stop_capturing(void)
{
enum v4l2_buf_type type; pr_debug("%s: called!\n", __func__); switch (io) {
case IO_METHOD_READ:
/* Nothing to do. */
break; case IO_METHOD_MMAP: //会执行下面的
case IO_METHOD_USERPTR:
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (- == xioctl(fd, VIDIOC_STREAMOFF, &type))
errno_exit("VIDIOC_STREAMOFF");
break;
}
} static void start_capturing(void)
{
unsigned int i;
enum v4l2_buf_type type;
int err; pr_debug("%s: called!\n", __func__); pr_debug("\tn_buffers: %d\n", n_buffers); switch (io) {
case IO_METHOD_READ:
/* Nothing to do. */
break; case IO_METHOD_MMAP:
for (i = ; i < n_buffers; ++i) {
struct v4l2_buffer buf; pr_debug("\ti: %d\n", i); CLEAR(buf);
buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = i; pr_debug("\tbuf.index: %d\n", buf.index); err == xioctl(fd, VIDIOC_QBUF, &buf);
pr_debug("\terr: %d\n", err); if (- == err)
errno_exit("VIDIOC_QBUF"); pr_debug("\tbuffer queued!\n");
} pr_debug("Before STREAMON\n");
type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (- == xioctl(fd, VIDIOC_STREAMON, &type))
errno_exit("VIDIOC_STREAMON");
pr_debug("After STREAMON\n");
break; case IO_METHOD_USERPTR: break;
}
} static void uninit_device(void)
{
unsigned int i; pr_debug("%s: called!\n", __func__); switch (io) {
case IO_METHOD_READ:
free(buffers[].start);
break; case IO_METHOD_MMAP:
for (i = ; i < n_buffers; ++i)
if (- == munmap(buffers[i].start, buffers[i].length))
errno_exit("munmap");
break; case IO_METHOD_USERPTR:
for (i = ; i < n_buffers; ++i)
free(buffers[i].start);
break;
} free(buffers);
} static void init_read(unsigned int buffer_size)
{
pr_debug("%s: called!\n", __func__); buffers = calloc(, sizeof(*buffers)); if (!buffers) {
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
} buffers[].length = buffer_size;
buffers[].start = malloc(buffer_size); if (!buffers[].start) {
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
}
} static void init_mmap(void) //(3)
{
struct v4l2_requestbuffers req; pr_debug("%s: called!\n", __func__); CLEAR(req); req.count = ;
req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
req.memory = V4L2_MEMORY_MMAP; if (- == xioctl(fd, VIDIOC_REQBUFS, &req)) {
if (EINVAL == errno) {
fprintf(stderr, "%s does not support "
"memory mapping\n", dev_name);
exit(EXIT_FAILURE);
} else {
errno_exit("VIDIOC_REQBUFS");
}
}
pr_debug("\treq.count: %d\n", req.count);
pr_debug("\treq.type: %d\n", req.type);
pr_debug("\treq.memory: %d\n", req.memory);
pr_debug("\n"); if (req.count < ) {
fprintf(stderr, "Insufficient buffer memory on %s\n",
dev_name);
exit(EXIT_FAILURE);
} buffers = calloc(req.count, sizeof(*buffers)); if (!buffers) {
fprintf(stderr, "Out of memory\n");
exit(EXIT_FAILURE);
} for (n_buffers = ; n_buffers < req.count; ++n_buffers) {
struct v4l2_buffer buf; CLEAR(buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
buf.memory = V4L2_MEMORY_MMAP;
buf.index = n_buffers; if (- == xioctl(fd, VIDIOC_QUERYBUF, &buf))
errno_exit("VIDIOC_QUERYBUF"); pr_debug("\tbuf.index: %d\n", buf.index);
pr_debug("\tbuf.type: %d\n", buf.type);
pr_debug("\tbuf.bytesused: %d\n", buf.bytesused);
pr_debug("\tbuf.flags: %d\n", buf.flags);
pr_debug("\tbuf.field: %d\n", buf.field);
pr_debug("\tbuf.timestamp.tv_sec: %ld\n", (long) buf.timestamp.tv_sec);
pr_debug("\tbuf.timestamp.tv_usec: %ld\n", (long) buf.timestamp.tv_usec);
pr_debug("\tbuf.timecode.type: %d\n", buf.timecode.type);
pr_debug("\tbuf.timecode.flags: %d\n", buf.timecode.flags);
pr_debug("\tbuf.timecode.frames: %d\n", buf.timecode.frames);
pr_debug("\tbuf.timecode.seconds: %d\n", buf.timecode.seconds);
pr_debug("\tbuf.timecode.minutes: %d\n", buf.timecode.minutes);
pr_debug("\tbuf.timecode.hours: %d\n", buf.timecode.hours);
pr_debug("\tbuf.timecode.userbits: %d,%d,%d,%d\n",
buf.timecode.userbits[],
buf.timecode.userbits[],
buf.timecode.userbits[],
buf.timecode.userbits[]);
pr_debug("\tbuf.sequence: %d\n", buf.sequence);
pr_debug("\tbuf.memory: %d\n", buf.memory);
pr_debug("\tbuf.m.offset: %d\n", buf.m.offset);
pr_debug("\tbuf.length: %d\n", buf.length);
pr_debug("\tbuf.input: %d\n", buf.input);
pr_debug("\n"); buffers[n_buffers].length = buf.length;
buffers[n_buffers].start =
mmap(NULL /* start anywhere */,
buf.length,
PROT_READ | PROT_WRITE /* required */,
MAP_SHARED /* recommended */,
fd, buf.m.offset); if (MAP_FAILED == buffers[n_buffers].start)
errno_exit("mmap");
}
} static void init_device(void) //static表示次函数只能在本文件中调用
{
struct v4l2_capability cap;
struct v4l2_cropcap cropcap;
struct v4l2_crop crop;
struct v4l2_format fmt;
unsigned int min; pr_debug("%s: called!\n", __func__); if (- == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
if (EINVAL == errno) {
fprintf(stderr, "%s is no V4L2 device\n",
dev_name);
exit(EXIT_FAILURE);
} else {
errno_exit("VIDIOC_QUERYCAP");
}
} pr_debug("\tdriver: %s\n"
"\tcard: %s \n"
"\tbus_info: %s\n",
cap.driver, cap.card, cap.bus_info);
pr_debug("\tversion: %u.%u.%u\n",
(cap.version >> ) & 0xFF,
(cap.version >> ) & 0xFF,
cap.version & 0xFF);
pr_debug("\tcapabilities: 0x%08x\n", cap.capabilities); if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
fprintf(stderr, "%s is no video capture device\n",
dev_name);
exit(EXIT_FAILURE);
} /* Select video input, video standard and tune here. */ CLEAR(cropcap); cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if ( == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) {
pr_debug("\tcropcap.type: %d\n", cropcap.type);
pr_debug("\tcropcap.bounds.left: %d\n", cropcap.bounds.left);
pr_debug("\tcropcap.bounds.top: %d\n", cropcap.bounds.top);
pr_debug("\tcropcap.bounds.width: %d\n", cropcap.bounds.width);
pr_debug("\tcropcap.bounds.height: %d\n", cropcap.bounds.height); pr_debug("\tcropcap.defrect.left: %d\n", cropcap.defrect.left);
pr_debug("\tcropcap.defrect.top: %d\n", cropcap.defrect.top);
pr_debug("\tcropcap.defrect.width: %d\n", cropcap.defrect.width);
pr_debug("\tcropcap.defrect.height: %d\n", cropcap.defrect.height); pr_debug("\tcropcap.pixelaspect.numerator: %d\n", cropcap.pixelaspect.numerator);
pr_debug("\tcropcap.pixelaspect.denominator: %d\n", cropcap.pixelaspect.denominator);
pr_debug("\n"); CLEAR(crop);
crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
crop.c = cropcap.defrect; /* reset to default */ if (- == xioctl(fd, VIDIOC_S_CROP, &crop)) {
switch (errno) {
case EINVAL:
/* Cropping not supported. */
break;
default:
/* Errors ignored. */
pr_debug("\tcropping not supported\n");
break;
}
}
} else {
/* Errors ignored. */
} CLEAR(fmt); fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
if (force_format) {
fmt.fmt.pix.width = FORCED_WIDTH;
fmt.fmt.pix.height = FORCED_HEIGHT;
fmt.fmt.pix.pixelformat = FORCED_FORMAT;
fmt.fmt.pix.field = FORCED_FIELD; pr_debug("\tfmt.fmt.pix.pixelformat: %c,%c,%c,%c\n",
fmt.fmt.pix.pixelformat & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF
);
pr_debug("\n"); if (- == xioctl(fd, VIDIOC_S_FMT, &fmt))
errno_exit("VIDIOC_S_FMT"); /* Note VIDIOC_S_FMT may change width and height. */
} else {
/* Preserve original settings as set by v4l2-ctl for example */
if (- == xioctl(fd, VIDIOC_G_FMT, &fmt))
errno_exit("VIDIOC_G_FMT"); fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
pr_debug("\tfmt.fmt.pix.pixelformat: %c,%c,%c,%c\n",
fmt.fmt.pix.pixelformat & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF,
(fmt.fmt.pix.pixelformat >> ) & 0xFF
); } /* Buggy driver paranoia. */
min = fmt.fmt.pix.width * ;
if (fmt.fmt.pix.bytesperline < min)
fmt.fmt.pix.bytesperline = min;
min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
if (fmt.fmt.pix.sizeimage < min)
fmt.fmt.pix.sizeimage = min; switch (io) {
case IO_METHOD_READ:
init_read(fmt.fmt.pix.sizeimage);
break; case IO_METHOD_MMAP:
init_mmap();
break; case IO_METHOD_USERPTR: break;
}
} static void close_device(void)
{
pr_debug("%s: called!\n", __func__); if (- == close(fd))//==可以防止你写成=(相当与赋值)这样条件始终成立
errno_exit("close"); fd = -;
} static void open_device(void)//
{
struct stat st; pr_debug("%s: called!\n", __func__);//_func_表示此时在那个函数里面 if (- == stat(dev_name, &st)) {//获取文件信息
fprintf(stderr, "Cannot identify '%s': %d, %s\n",
dev_name, errno, strerror(errno));
exit(EXIT_FAILURE);//非正常退出 EXIT_FAILURE=1, EXIT_SUCCSES=0 正常退出
} if (!S_ISCHR(st.st_mode)) {
fprintf(stderr, "%s is no device\n", dev_name);
exit(EXIT_FAILURE);
} fd = open(dev_name, O_RDWR /* required */ | O_NONBLOCK, );//非阻塞模式打开文件 if (- == fd) {
fprintf(stderr, "Cannot open '%s': %d, %s\n",
dev_name, errno, strerror(errno));
exit(EXIT_FAILURE);
}
} static void usage(FILE *fp, int argc, char **argv)
{
fprintf(fp,
"Usage: %s [options]\n\n"
"Version 1.3\n"
"Options:\n"
"-d | --device name Video device name [%s]\n"
"-h | --help Print this message\n"
"-m | --mmap Use memory mapped buffers [default]\n"
"-r | --read Use read() calls\n"
"-u | --userp Use application allocated buffers\n"
"-o | --output Outputs stream to stdout\n"
"-f | --format Force format to 640x480 YUYV\n"
"-c | --count Number of frames to grab [%i]\n"
"-v | --verbose Verbose output\n"
"",
argv[], dev_name, frame_count);
}
//关于命令解析见百度getopt-long;
static const char short_options[] = "d:hmruofc:v";// 短选项 :表示带参数 static const struct option //长选项
long_options[] = {
{ "device", required_argument, NULL, 'd' },
{ "help", no_argument, NULL, 'h' },
{ "mmap", no_argument, NULL, 'm' },
{ "read", no_argument, NULL, 'r' },
{ "userp", no_argument, NULL, 'u' },
{ "output", no_argument, NULL, 'o' },
{ "format", no_argument, NULL, 'f' },
{ "count", required_argument, NULL, 'c' },
{ "verbose", no_argument, NULL, 'v' },
{ , , , }
}; int main(int argc, char **argv)
{
dev_name = "/dev/video0"; for (;;) {
int idx;
int c; c = getopt_long(argc, argv,
short_options, long_options, &idx); if (- == c)
break; switch (c) {
case : /* getopt_long() flag */
break; case 'd':
dev_name = optarg;
break; case 'h':
usage(stdout, argc, argv);
exit(EXIT_SUCCESS); case 'm':
io = IO_METHOD_MMAP;
break; case 'r':
io = IO_METHOD_READ;
break; case 'u':
io = IO_METHOD_USERPTR;
break; case 'o':
out_buf++;
break; case 'f':
force_format++;
break; case 'c':
errno = ;
frame_count = strtol(optarg, NULL, );
if (errno)
errno_exit(optarg);
break; case 'v':
verbose = ;
break; default:
usage(stderr, argc, argv);
exit(EXIT_FAILURE);
}
} if((fp = fopen(video_name,"wa+")) == NULL)
{
perror("Fail to fopen");
exit(EXIT_FAILURE);
} open_device();
init_device();
start_capturing();
mainloop();
stop_capturing();
uninit_device();
close_device();
fprintf(stderr, "\n");
return ;
}

v4l2采集视频和图片源码的更多相关文章

  1. java GUI 返回图片源码

    返回图片源码,重开一个类粘贴即可 package cn.littlepage.game; import java.awt.Image; import java.awt.image.BufferedIm ...

  2. ThinkCMF-上传多个图片源码解读

    关键函数: /** * 多图上传 * @param dialog_title 上传对话框标题 * @param container_selector 图片容器 * @param item_tpl_wr ...

  3. Java导出Highcharts生成的图表为图片源码

    本文转载自:http://blog.csdn.net/dengsilinming/article/details/7352054 需要的jar包: 需要的js文件:(可以通过http://www.hi ...

  4. php抓取网站图片源码

    <?php /*完成网页内容捕获功能*/ function get_img_url($site_name){     $site_fd = fopen($site_name, "r&q ...

  5. 【转】基于V4L2的视频驱动开发

    编写基于V4L2视频驱动主要涉及到以下几个知识点:1> 摄像头方面的知识 要了解选用的摄像头的特性,包括访问控制方法.各种参数的配置方法.信号输出类型等.2> Camera解码器.控制器 ...

  6. 基于V4L2的视频驱动开发【转】

    转自:http://blog.chinaunix.net/uid-10747583-id-298573.html Tags:V4L2驱动框架.API.操作流程…… 原文地址:http://www.ee ...

  7. Crackme006 - 全新160个CrackMe学习系列(图文|视频|注册机源码)

    知乎:逆向驿站 原文链接 CrackMe006 | 难度适中适合练手 |160个CrackMe深度解析(图文+视频+注册机源码) crackme006,依然是delphi的,而且没壳子,条线比较清晰, ...

  8. 大数据入门第七天——MapReduce详解(二)切片源码浅析与自定义patition

    一.mapTask并行度的决定机制 1.概述 一个job的map阶段并行度由客户端在提交job时决定 而客户端对map阶段并行度的规划的基本逻辑为: 将待处理数据执行逻辑切片(即按照一个特定切片大小, ...

  9. [转]GStreamer资料(摄像头采集,视频保存,远程监控)DVR

    http://blog.csdn.net/wzwxiaozheng/archive/2010/12/26/6099397.aspx GStreamer资料整理(包括摄像头采集,视频保存,远程监控,流媒 ...

随机推荐

  1. Symbol not found for architecture arm64 错误

    如果Archiectures和Valid Architectures都是对的,需要检查Other Linker Flags是否添加$(inherited),如果还不行,检查Library Search ...

  2. ldconfig和ldd用法

    一.ldconfig ldconfig是一个动态链接库管理命令,为了让动态链接库为系统所共享,还需运行动态链接库的管理命令--ldconfig. ldconfig 命令的用途,主要是在默认搜寻目录(/ ...

  3. Node-webkit 资料笔记

    静不下心写学习笔记了,因为发现了这篇文章:<用node-webkit开发多平台的桌面客户端> 另外官网上针对“package.json”的配置参数也已经很详尽了,连我英文不好的也差不多能看 ...

  4. 学习Google Protocol buffer之语法

    上一篇结尾的时候问了几个问题,其实主要就是这个protoBuffer协议的语法,弄清楚语法后边才好开展工作嘛,不然大眼而对小眼儿,互相不认识,就没法玩耍了.其实就是学习怎么用google提供的这套 p ...

  5. iwork 09 可以用的序列号

    E4RJ-YKHP-9ER4-WK9Y-H4UM-5S2G9MU-9U9J-KN4M-4PAE-DYNA-5S2EGMU-3PKP-NN9G-3JW4-3RAD-5S2

  6. @@IDENTITY与SCOPE_IDENTITY的用法

    SCOPE_IDENTITY   和   @@IDENTITY   的作用都是取得返回在当前会话中的任何表内所生成的最后一个标识值,简单的说就是在执行一条插入语句之后使用@@IDENTITY的全局变量 ...

  7. Linux下profile environment bashrc的区别

        先将export LANG=zh_CN加入/etc/profile ,退出系统重新登录,登录提示显示英文.将/etc/profile 中的export LANG=zh_CN删除,将LNAG=z ...

  8. [LeetCode 119] - 杨辉三角形II(Pascal's Triangle II)

    问题 给出一个索引k,返回杨辉三角形的第k行. 例如,给出k = 3,返回[1, 3, 3, 1] 注意: 你可以优化你的算法使之只使用O(k)的额外空间吗? 初始思路 首先来复习复习杨辉三角形的性质 ...

  9. java.net.SocketTimeoutException: Read timed out

    If you get java.net.SocketTimeoutException: Read timed out exception Try setting own timeout value w ...

  10. c#,Model 实体转json,字符串转json

    public class JsonF { #region 字符串转json /// <summary> /// 字符串转json /// </summary> /// < ...