LINUX下采集V4L2摄像头数据源码

#include <pthread.h> #include <asm/types.h> /* for videodev2.h */ #include <fcntl.h> /* low-level i/o */ #include <unistd.h> #include <errno.h> #include <malloc.h> #include <sys/stat.h> #include <sys/types.h> //#include <sys/time.h> #include <time.h> #include <sys/mman.h> #include <sys/ioctl.h> #include <stdio.h> #include <stdlib.h> #include <string.h> #include <assert.h> #include <linux/videodev2.h> #include <dirent.h> #include "video_capture.h" #include "h264encoder.h" typedef enum{ FRAME_INVALID=0, FRAME_VALID, }frame_state_t; typedef struct _raw_frame{ pthread_mutex_t lock; pthread_cond_t cond; uint8_t * buf; frame_state_t state; struct _raw_frame* next; }raw_frame_t; typedef struct { }raw_frame_queue_t; #define MAX_FRAME_BUF_SIZE 10 #define FRAME_SIZE (640*480*2) #define BUF_SIZE (FRAME_SIZE*10) raw_frame_t * raw_frame_read_head; raw_frame_t * raw_frame_write_head; raw_frame_t raw_frame_buf[MAX_FRAME_BUF_SIZE]; unsigned char encodebuf[FRAME_SIZE]; #define CLEAR(x) memset (&(x), 0, sizeof (x)) typedef unsigned char uint8_t; static char *dev_name = "/dev/video0"; char h264_file_name[100] = "zgy.h264\0"; FILE *h264_fp; uint8_t *h264_buf; char yuv_file_name[100] = "zgy_640x480.yuv\0"; FILE *yuv_fp; unsigned int n_buffers = 0; DIR *dirp; Encoder en; int cnt = 0; unsigned char *framebuf=0; void InitFrameQueue(void) { int i; raw_frame_t* p; framebuf = malloc(BUF_SIZE); for(i=0;i<MAX_FRAME_BUF_SIZE;i++) { p=&raw_frame_buf[i]; p->buf=framebuf+i*FRAME_SIZE; pthread_mutex_init(&p->lock,NULL); pthread_cond_init(&p->cond,NULL); p->state = FRAME_INVALID; if(i==0) { raw_frame_write_head=raw_frame_read_head = p; p->next = &raw_frame_buf[i+1]; } else if(i>=(MAX_FRAME_BUF_SIZE-1)) { p->next = &raw_frame_buf[0];//���ζ��� } else p->next = &raw_frame_buf[i+1]; } } void FreeFrameQueue(void) { int i; raw_frame_t* p; for(i=0;i<MAX_FRAME_BUF_SIZE;i++) { p=&raw_frame_buf[i]; pthread_mutex_destroy(&p->lock); pthread_cond_destroy(&p->cond); p->buf=NULL; p->next=NULL; } free(framebuf); framebuf=NULL; } void PutFrameQueue(unsigned char* buf,int len) { static int putcnt=0; raw_frame_t* ptmp=raw_frame_write_head; if(ptmp) { pthread_mutex_lock(&ptmp->lock); if(ptmp->state==FRAME_INVALID) { memcpy(ptmp->buf,buf,FRAME_SIZE); ptmp->state=FRAME_VALID; pthread_cond_signal(&ptmp->cond); raw_frame_write_head=raw_frame_write_head->next; printf("put =%d\n",putcnt++); } pthread_mutex_unlock(&ptmp->lock); } } int GetFrameQueue(unsigned char*buf) { static int getcnt=0; int len =0; raw_frame_t* ptmp=raw_frame_read_head; if(ptmp) { pthread_mutex_lock(&ptmp->lock); if(ptmp->state==FRAME_INVALID) { extern int encodethreadexit; if(encodethreadexit) { printf("encode thread exit\n"); pthread_mutex_unlock(&ptmp->lock); exit(0); } pthread_cond_wait(&ptmp->cond,&ptmp->lock); } memcpy(buf,ptmp->buf,FRAME_SIZE); ptmp->state=FRAME_INVALID; raw_frame_read_head=raw_frame_read_head->next; pthread_mutex_unlock(&ptmp->lock); len = FRAME_SIZE; printf("get =%d\n",getcnt++); } return len; } int CheckFrameQueueEmty(void) { int ret=0; raw_frame_t* ptmp=raw_frame_read_head; if(ptmp) { pthread_mutex_lock(&ptmp->lock); if(ptmp->state==FRAME_INVALID) { ret =1; } pthread_mutex_unlock(&ptmp->lock); } return ret; } void errno_exit(const char *s) { fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno)); exit(EXIT_FAILURE); } int xioctl(int fd, int request, void *arg) { int r = 0; do { r = ioctl(fd, request, arg); } while (-1 == r && EINTR == errno); return r; } void open_camera(struct camera *cam) { struct stat st; if (-1 == stat(cam->device_name, &st)) { fprintf(stderr, "Cannot identify '%s': %d, %s\n", cam->device_name, errno, strerror(errno)); exit(EXIT_FAILURE); } if (!S_ISCHR(st.st_mode)) { fprintf(stderr, "%s is no device\n", cam->device_name); exit(EXIT_FAILURE); } cam->fd = open(cam->device_name, O_RDWR, 0); // | O_NONBLOCK if (-1 == cam->fd) { fprintf(stderr, "Cannot open '%s': %d, %s\n", cam->device_name, errno, strerror(errno)); exit(EXIT_FAILURE); } } void close_camera(struct camera *cam) { if (-1 == close(cam->fd)) errno_exit("close"); cam->fd = -1; } void init_file() { h264_fp = fopen(h264_file_name, "wa+"); yuv_fp = fopen(yuv_file_name, "wa+"); } void close_file() { fclose(h264_fp); fclose(yuv_fp); } void init_encoder(struct camera *cam) { compress_begin(&en, cam->width, cam->height); h264_buf = (uint8_t *) malloc( sizeof(uint8_t) * cam->width * cam->height * 3); // 设置缓冲区 } void close_encoder() { compress_end(&en); free(h264_buf); } void encode_frame(uint8_t *yuv_frame, size_t yuv_length) { int h264_length = 0; //这里有一个问题，通过测试发现前6帧都是0，所以这里我跳过了为0的帧 if (yuv_frame[0] == '\0') return; #if 0 h264_length = compress_frame(&en, -1, yuv_frame, h264_buf); if (h264_length > 0) { //写h264文件 fwrite(h264_buf, h264_length, 1, h264_fp); } #endif //写yuv文件 fwrite(yuv_frame, yuv_length, 1, yuv_fp); } void encode_frame_NEW(void) { int len; len=GetFrameQueue(encodebuf); if(len) fwrite(encodebuf, len, 1, yuv_fp); } int read_and_encode_frame(struct camera *cam) { struct v4l2_buffer buf; printf("in read_frame\n"); CLEAR(buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; //this operator below will change buf.index and (0 <= buf.index <= 3) if (-1 == xioctl(cam->fd, VIDIOC_DQBUF, &buf)) { switch (errno) { case EAGAIN: return 0; case EIO: /* Could ignore EIO, see spec. */ /* fall through */ default: errno_exit("VIDIOC_DQBUF"); } } //encode_frame(cam->buffers[buf.index].start, buf.length); PutFrameQueue(cam->buffers[buf.index].start,buf.length); if (-1 == xioctl(cam->fd, VIDIOC_QBUF, &buf)) errno_exit("VIDIOC_QBUF"); return 1; } void start_capturing(struct camera *cam) { unsigned int i; enum v4l2_buf_type type; for (i = 0; i < n_buffers; ++i) { struct v4l2_buffer buf; CLEAR(buf); buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; buf.memory = V4L2_MEMORY_MMAP; buf.index = i; if (-1 == xioctl(cam->fd, VIDIOC_QBUF, &buf)) errno_exit("VIDIOC_QBUF"); } type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == xioctl(cam->fd, VIDIOC_STREAMON, &type)) errno_exit("VIDIOC_STREAMON"); } void stop_capturing(struct camera *cam) { enum v4l2_buf_type type; type = V4L2_BUF_TYPE_VIDEO_CAPTURE; if (-1 == xioctl(cam->fd, VIDIOC_STREAMOFF, &type)) errno_exit("VIDIOC_STREAMOFF"); } void uninit_camera(struct camera *cam) { unsigned int i; for (i = 0; i < n_buffers; ++i) if (-1 == munmap(cam->buffers[i].start, cam->buffers[i].length)) errno_exit("munmap"); free(cam->buffers); } void init_mmap(struct camera *cam) { struct v4l2_requestbuffers req; CLEAR(req); req.count = 4; req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE; req.memory = V4L2_MEMORY_MMAP; //分配内存 if (-1 == xioctl(cam->fd, VIDIOC_REQBUFS, &req)) { if (EINVAL == errno) { fprintf(stderr, "%s does not support " "memory mapping\n", cam->device_name); exit(EXIT_FAILURE); } else { errno_exit("VIDIOC_REQBUFS"); } } if (req.count < 2) { fprintf(stderr, "Insufficient buffer memory on %s\n", cam->device_name); exit(EXIT_FAILURE); } cam->buffers = calloc(req.count, sizeof(*(cam->buffers))); if (!cam->buffers) { fprintf(stderr, "Out of memory\n"); exit(EXIT_FAILURE); } for (n_buffers = 0; 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; //将VIDIOC_REQBUFS中分配的数据缓存转换成物理地址 if (-1 == xioctl(cam->fd, VIDIOC_QUERYBUF, &buf)) errno_exit("VIDIOC_QUERYBUF"); cam->buffers[n_buffers].length = b