linux系统v4l2简单编程-抓帧

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <getopt.h>           
#include <fcntl.h>            
#include <unistd.h>
#include <errno.h>
#include <malloc.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/time.h>
#include <sys/mman.h>
#include <sys/ioctl.h>


#include <asm/types.h>        
#include <linux/videodev2.h>
#include <linux/v4l2-mediabus.h>


#define CAMERA_DEVICE "/dev/video1"
#define CAPTURE_FILE "frame.yuv"


int VIDEO_WIDTH = 1280;
int VIDEO_HEIGHT = 720;
#define VIDEO_FORMAT V4L2_MBUS_FMT_YUYV8_2X8
//int VIDEO_FORMAT = V4L2_MBUS_FMT_RGB888_1X24;
#define BUFFER_COUNT 10


typedef struct VideoBuffer {
    void   *start;
    size_t  length;
} VideoBuffer;


int main(int argc, char **argv)
{
    int i, ret;


if(argc >= 4){
VIDEO_WIDTH = atoi(argv[1]);
VIDEO_HEIGHT = atoi(argv[2]);
// VIDEO_FORMAT = atoi(argv[3]);
    }
    
    printf("www  pix = %dx%d@%x\n",VIDEO_WIDTH,VIDEO_HEIGHT,VIDEO_FORMAT);
    // 打开设备
    int fd;
    fd = open(CAMERA_DEVICE, O_RDWR, 0);
    if (fd < 0) {
        printf("Open %s failed\n", CAMERA_DEVICE);
        return -1;
    }


    struct v4l2_streamparm stream_parm;
    ioctl(fd, VIDIOC_G_PARM, &stream_parm);
    stream_parm.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    ioctl(fd, VIDIOC_S_PARM, &stream_parm);
    // 获取驱动信息
    struct v4l2_capability cap;
    ret = ioctl(fd, VIDIOC_QUERYCAP, &cap);
    if (ret < 0) {
        printf("VIDIOC_QUERYCAP failed (%d)\n", ret);
        return ret;
    }
    // Print capability infomations
    printf("Capability Informations:\n");
    printf(" driver: %s\n", cap.driver);
    printf(" card: %s\n", cap.card);
    printf(" bus_info: %s\n", cap.bus_info);
    printf(" version: %08X\n", cap.version);
    printf(" capabilities: %08X\n", cap.capabilities);
 
    printf("----------------------------\n");
    // 设置视频格式
    struct v4l2_format fmt;
    memset(&fmt, 0, sizeof(fmt));
    fmt.type                = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width       = VIDEO_WIDTH;
    fmt.fmt.pix.height      = VIDEO_HEIGHT;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
    fmt.fmt.pix.field       = V4L2_FIELD_ALTERNATE;
    ret = ioctl(fd, VIDIOC_S_FMT, &fmt);
    if (ret < 0) {
        printf("VIDIOC_S_FMT failed (%d)\n", ret);
        return ret;
    }


    // 获取视频格式
    ret = ioctl(fd, VIDIOC_G_FMT, &fmt);
    if (ret < 0) {
        printf("VIDIOC_G_FMT failed (%d)\n", ret);
        return ret;
    }
    // Print Stream Format
    printf("Stream Format Informations:\n");
    printf(" type: %d\n", fmt.type);
    printf(" width: %d\n", fmt.fmt.pix.width);
    printf(" height: %d\n", fmt.fmt.pix.height);
    char fmtstr[8];
    memset(fmtstr, 0, 8);
    memcpy(fmtstr, &fmt.fmt.pix.pixelformat, 4);
    printf(" pixelformat: %s\n", fmtstr);
    printf(" field: %d\n", fmt.fmt.pix.field);
    printf(" bytesperline: %d\n", fmt.fmt.pix.bytesperline);
    printf(" sizeimage: %d\n", fmt.fmt.pix.sizeimage);
    printf(" colorspace: %d\n", fmt.fmt.pix.colorspace);
    printf(" priv: %d\n", fmt.fmt.pix.priv);
    printf(" raw_date: %s\n", fmt.fmt.raw_data);


    // 请求分配内存
    struct v4l2_requestbuffers reqbuf;
    
    reqbuf.count = BUFFER_COUNT;
    reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    reqbuf.memory = V4L2_MEMORY_MMAP;
    
    ret = ioctl(fd , VIDIOC_REQBUFS, &reqbuf);
    if(ret < 0) {
        printf("VIDIOC_REQBUFS failed (%d)\n", ret);
        return ret;
    }


    // 获取空间
    VideoBuffer*  framebuf = calloc( reqbuf.count, sizeof(VideoBuffer) );
    struct v4l2_buffer buf;


    for (i = 0; i < reqbuf.count; i++) 
    {
        buf.index = i;
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        ret = ioctl(fd , VIDIOC_QUERYBUF, &buf);
        if(ret < 0) {
            printf("VIDIOC_QUERYBUF (%d) failed (%d)\n", i, ret);
            return ret;
        }


        // mmap buffer
        framebuf[i].length = buf.length;
        framebuf[i].start = (char *) mmap(0, buf.length, PROT_READ|PROT_WRITE, MAP_SHARED, fd, buf.m.offset);
        if (framebuf[i].start == MAP_FAILED) {
            printf("mmap (%d) failed: %s\n", i, strerror(errno));
            return -1;
        }
    
        // Queen buffer
        ret = ioctl(fd , VIDIOC_QBUF, &buf);
        if (ret < 0) {
            printf("VIDIOC_QBUF (%d) failed (%d)\n", i, ret);
            return -1;
        }


        printf("Frame buffer %d: address=0x%x, length=%d\n", i, (unsigned int)framebuf[i].start, framebuf[i].length);
    }


    // 开始录制
    enum v4l2_buf_type type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    ret = ioctl(fd, VIDIOC_STREAMON, &type);
    if (ret < 0) {
        printf("VIDIOC_STREAMON failed (%d)\n", ret);
        return ret;
    }


    // Get frame
    ret = ioctl(fd, VIDIOC_DQBUF, &buf);
    if (ret < 0) {
        printf("VIDIOC_DQBUF failed (%d)\n", ret);
        return ret;
    }


    // Process the frame
    FILE *fp = fopen(CAPTURE_FILE, "wb");
    if (fp < 0) {
        printf("open frame data file failed\n");
        return -1;
    }
    fwrite(framebuf[buf.index].start, 1, buf.length, fp);
    fflush(fp);
    fclose(fp);
    system("sync");
    printf("Capture one frame saved in %s\n", CAPTURE_FILE);


    // Re-queen buffer
    ret = ioctl(fd, VIDIOC_QBUF, &buf);
    if (ret < 0) {
        printf("VIDIOC_QBUF failed (%d)\n", ret);
        return ret;
    }
    
close(fd);
    // Release the resource
    for (i=0; i< 4; i++) 
    {
        munmap(framebuf[i].start, framebuf[i].length);
    }
    
    printf("Camera test Done.\n");
    return 0;

}

=========================================

附android的make文件

Android.mk:

LOCAL_PATH:= $(call my-dir)




include $(CLEAR_VARS)


#app_main.cpp


LOCAL_SRC_FILES:= \
capture.c


LOCAL_SHARED_LIBRARIES := \
libcutils \
libutils \
liblog




LOCAL_MODULE := videotest
LOCAL_MODULE_TAGS := eng


include $(BUILD_EXECUTABLE)