OK6410预览并实现截图操作(RGB565）

涉及内容：

1、v4l2操作摄像头

2、RGB565转BMP（RGB16）文件

参考代码：

#include <sys/time.h>#include <sys/types.h>#include <asm/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>#include <stdlib.h>#include <stdio.h>#include <string.h>#include <sys/mman.h>#include <errno.h>#include <jpeglib.h>#include <linux/fs.h>#include <linux/kernel.h>#include "videodev2.h"#include <linux/fb.h>#include "jpeglib.h"#define CTRL_NUM 100#define WIDTH               480#define HEIGHT              272//文件头struct tagBITMAPFILEHEADER{    unsigned long bfSize;    unsigned long bfLeft;    unsigned long bfOffBits;};// bmp图像的位图信息头struct tagBITMAPINFOHEADER{    unsigned long biSize;    unsigned long bmpWidth;    unsigned long bmpHeight;    unsigned short biPlanes;    unsigned short bicolors;    unsigned long isCompressed;    unsigned long biMapSize;    unsigned long biHorizontal;    unsigned long biVertical;    unsigned long biusedcolors;    unsigned long biimportcolors; };#define V4L2_DEV_NODE "/dev/video1"#define FB_DEV_NODE "/dev/fb0"typedef struct v4l2_input    V_INPUT;typedef struct v4l2_format   V_FORMAT;typedef struct v4l2_fmtdesc  V_FMTDESC;typedef struct v4l2_queryctrl V_QRYCTRL;typedef struct fb_var_screeninfo F_VINFO;#define V4L2_FMT_IN0#define V4L2_FMT_OUT1unsigned char *preview_buf;static void writebmp(int data_fd){int i,j,k,size;int ret;unsigned char *buf1 = (unsigned char *)malloc(sizeof(unsigned char) * 480*272*2);memcpy(buf1, preview_buf, 480*272*2);unsigned short buf[WIDTH*HEIGHT]={0};printf("Write buf[i*WIDTH+k] begin!\n");for(i=0;i<HEIGHT;i++){    for(j=0;j<WIDTH;j++)    {*(buf+i*WIDTH+j)= (buf1[i*WIDTH*2+j*2])|(buf1[i*WIDTH*2+j*2+1]<<8);//if(i<1)//printf("(%d,%d,0x%4x)\n",i,j,*(buf+i*WIDTH+j));}}printf("Write buf[i*WIDTH+k] end!\n");unsigned short bmp[WIDTH*HEIGHT];    struct tagBITMAPFILEHEADER bfhead;struct tagBITMAPINFOHEADER binfohead;size=HEIGHT*WIDTH;bfhead.bfSize=0x36+size*2;bfhead.bfLeft=0;bfhead.bfOffBits=0x36;binfohead.biSize=0x28;binfohead.bmpWidth=WIDTH;binfohead.bmpHeight=HEIGHT;binfohead.biPlanes=1;binfohead.bicolors=0x10;binfohead.isCompressed=0;binfohead.biMapSize=size*2;binfohead.biHorizontal=0x0b13;binfohead.biVertical=0x0b13;binfohead.biusedcolors=0;binfohead.biimportcolors=0;for(i=0;i<HEIGHT;i++)for(j=0;j<WIDTH;j++)    *(bmp+i*WIDTH+j)=((buf[(HEIGHT-i)*WIDTH-WIDTH+j]&0xf800)>>1)|((buf[(HEIGHT-i)*WIDTH-WIDTH+j]&0x07c0)>>1)|((buf[(HEIGHT-i)*WIDTH-WIDTH+j]&0x1f));//翻转图像 //for (i=HEIGHT; i>=0;i--)//for(j=WIDTH;j>=0;j--)//*(bmp+i*WIDTH+j)=((buf[i*WIDTH+j]&0xf800)>>1)|((buf[i*WIDTH+j]&0x07c0)>>1)|((buf[i*WIDTH+j]&0x1f));write(data_fd,"BM",2);i=write(data_fd,&bfhead,sizeof(struct tagBITMAPFILEHEADER));printf("Write filehead %dbytes\n",i);i=write(data_fd,&binfohead,sizeof(struct tagBITMAPINFOHEADER));printf("Write infohead %dbytes\n",i);i=write(data_fd,bmp,size*2);printf("Write bitmap %dbytes\n",i);lseek(data_fd,SEEK_SET,4);}int main(void){int v4l2_fd = -1;int fb_fd = -1;int n=0;__u8 *fb_buf;__u32 screensize;V_FORMAT fmt;struct v4l2_capability caminfo;v4l2_fd = open(V4L2_DEV_NODE, O_RDWR);if (v4l2_fd < 0) {printf(" open video ERR\n");}fb_fd = open(FB_DEV_NODE, O_RDWR);if (fb_fd < 0) {printf(" open FB ERR\n");}screensize = 480 * 272 * 16 / 8;fb_buf = (__u8 *)mmap(0, screensize, PROT_READ | PROT_WRITE, MAP_SHARED,fb_fd, 0);if ((int)fb_buf == -1) {printf("Error: failed to map framebuffer device to memory.\n");close(fb_fd);return -1;}if((n =(ioctl(v4l2_fd, VIDIOC_QUERYCAP, &caminfo)))<0) printf("Error: failed to get camera info.%d\n",n); //设置图象模式 fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;fmt.fmt.pix.width = 480;fmt.fmt.pix.height = 272;fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB565;fmt.fmt.pix.priv = V4L2_FMT_OUT;if((ioctl(v4l2_fd, VIDIOC_S_FMT, &fmt))<0)printf("Error: failed to set video format.\n");int type = V4L2_BUF_TYPE_VIDEO_CAPTURE;if((ioctl(v4l2_fd, VIDIOC_STREAMON, &type))<0)printf("start to get pic %d\n",(int)fmt.fmt.pix.sizeimage);int ii = 0;while(1){n=read(v4l2_fd, fb_buf, 480*272*2);if (ii == 0 && n > 0) {int data_fd=-1;printf("read Data Length:%d\n", n);preview_buf =  malloc(n);memcpy(preview_buf, fb_buf, n);char bmpfilename[30];sprintf(bmpfilename, "/sdcard/photo%d.bmp",1);if((data_fd = open(bmpfilename,O_CREAT|O_RDWR,0777))<0){printf("Error: failed to creat photo.bmp.\n");return 0;}printf("bmpfilename is %s\n",bmpfilename);writebmp(data_fd);if(data_fd>0)                close(data_fd);free(preview_buf);    ii = 1;  }}}