h264 encode yuv v4l2

#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" #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.yuv\0"; FILE *yuv_fp; unsigned int n_buffers = 0; DIR *dirp; Encoder en; int cnt = 0; 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; 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); } //写yuv文件 fwrite(yuv_frame, yuv_length, 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); 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 = buf.length; cam->buffers[n_buffers].start = mmap(NULL /* start anywhere */, buf.length, PROT_READ | PROT_WRITE /* required */, MAP_SHARED /* recommended */, cam->fd, buf.m.offset); if (MAP_FAILED == cam->buffers[n_buffers].start) errno_exit("mmap"); } } void init_camera(struct camera *cam) { struct v4l2_capability *cap = &(cam->v4l2_cap); struct v4l2_cropcap *cropcap = &(cam->v4l2_cropcap); struct v4l2_crop *crop = &(cam->crop); struct v4l2_format *fmt = &(cam->v4l2_fmt); unsigned int min; if (-1 == xioctl(cam->fd, VIDIOC_QUERYCAP, cap)) { if (EINVAL == errno) { fprintf(stderr, "%s is no V4L2 device\n", cam->device_name); exit(EXIT_FAILURE); } else { errno_exit("VIDIOC_QUERYCAP"); } } if (!(cap->capabilities & V4L2_CAP_VIDEO_CAPTURE)) { fprintf(stderr, "%s is no video capture device\n", cam->device_name); exit(EXIT_FAILURE); } if (!(cap->capabilities & V4L2_CAP_STREAMING)) { fprintf(stderr, "%s does not support streaming i/o\n", cam->device_name); exit(EXIT_FAILURE); } //#ifdef DEBUG_CAM printf("\nVIDOOC_QUERYCAP\n"); printf("the camera driver is %s\n", cap->driver); printf("the camera card is %s\n", cap->card); printf("the camera bus info is %s\n", cap->bus_info); printf("the version is %d\n", cap->version); //#endif /* Select video input, video standard and tune here. */ CLEAR(*cropcap); cropcap->type = V4L2_BUF_TYPE_VIDEO_CAPTURE; crop->c.width = cam->width; crop->c.height = cam->height; crop->c.left = 0; crop->c.top = 0; crop->type = V4L2_BUF_TYPE_VIDEO_CAPTURE; CLEAR(*fmt); fmt->type = V4L2_BUF_TYPE_VIDEO_CAPTURE; fmt->fmt.pix.width = cam->width; fmt->fmt.pix.height = cam->height; fmt->fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV; //yuv422 // fmt->fmt.pix.pixelformat = V4L2_PIX_FMT_YUV420 //yuv420 但是我电脑不支持 fmt->fmt.pix.field = V4L2_FIELD_INTERLACED; //隔行扫描 if (-1 == xioctl(cam->fd, VIDIOC_S_FMT, fmt)) errno_exit("VIDIOC_S_FMT"); /* Note VIDIOC_S_FMT may change width and height. */ /* Buggy driver paranoia. */ min = fmt->fmt.pix.width * 2; 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; init_mmap(cam); } void v4l2_init(struct camera *cam) { open_camera(cam); init_camera(cam); start_capturing(cam); init_encoder(cam); init_file(); } void v4l2_close(struct camera *cam) { stop_capturing(cam); uninit_camera(cam); close_camera(cam); free(cam); close_file(); close_encoder(); }