forked from tTh/FloatImg
330 lines
7.6 KiB
C
330 lines
7.6 KiB
C
/*
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* V4L2 functions - ugly source code
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <fcntl.h> /* low-level i/o */
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#include <unistd.h>
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#include <errno.h>
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#include <sys/stat.h>
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#include <sys/mman.h>
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#include <sys/ioctl.h>
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#include <linux/videodev2.h>
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#include "../floatimg.h"
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#include "funcs.h"
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/* --------------------------------------------------------------------- */
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extern int verbosity;
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enum io_method {
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IO_METHOD_READ,
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IO_METHOD_MMAP,
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IO_METHOD_USERPTR,
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};
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struct buffer {
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void *start;
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size_t length;
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};
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static char *dev_name;
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static enum io_method io = IO_METHOD_MMAP;
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static int fd = -1;
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struct buffer *buffers;
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static unsigned int n_buffers;
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static int out_buf;
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static int force_format;
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static int frame_count = 70;
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static void errno_exit(const char *s)
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{
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fprintf(stderr, "%s error %d, %s\n", s, errno, strerror(errno));
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exit(EXIT_FAILURE);
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}
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static int xioctl(int fh, int request, void *arg)
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{
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int r;
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/* PLEASE EXPLAIN THAT CODE */
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do {
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r = ioctl(fh, request, arg);
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} while (-1 == r && EINTR == errno);
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return r;
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}
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/* --------------------------------------------------------------------- */
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/*
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*
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*/
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int open_device(char *device)
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{
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struct stat st;
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if (-1 == stat(device, &st)) {
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fprintf(stderr, "Cannot identify '%s': %d, %s\n",
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device, errno, strerror(errno));
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exit(EXIT_FAILURE);
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}
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if (!S_ISCHR(st.st_mode)) {
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fprintf(stderr, "%s is no device\n", device);
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exit(EXIT_FAILURE);
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}
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fd = open(device, O_RDWR /* required */ | O_NONBLOCK, 0);
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if (-1 == fd) {
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fprintf(stderr, "Cannot open '%s': %d, %s\n",
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device, errno, strerror(errno));
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exit(EXIT_FAILURE);
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}
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dev_name = strdup(device); /* XXX */
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if (verbosity) {
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fprintf(stderr, "device '%s' opened as #%d\n", device, fd);
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}
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return fd;
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}
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/* --------------------------------------------------------------------- */
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static void init_read(unsigned int buffer_size)
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{
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buffers = calloc(1, sizeof(*buffers));
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if (!buffers) {
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fprintf(stderr, "Out of memory\n");
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exit(EXIT_FAILURE);
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}
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buffers[0].length = buffer_size;
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buffers[0].start = malloc(buffer_size);
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if (!buffers[0].start) {
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fprintf(stderr, "Out of memory\n");
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exit(EXIT_FAILURE);
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}
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}
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static void init_mmap(void)
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{
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struct v4l2_requestbuffers req;
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memset(&req, 0, sizeof(req));
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req.count = 4;
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req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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req.memory = V4L2_MEMORY_MMAP;
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if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
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if (EINVAL == errno) {
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fprintf(stderr, "%s does not support "
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"memory mapping\n", dev_name);
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exit(EXIT_FAILURE);
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} else {
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errno_exit("VIDIOC_REQBUFS");
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}
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}
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if (req.count < 2) {
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fprintf(stderr, "Insufficient buffer memory on %s\n",
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dev_name);
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exit(EXIT_FAILURE);
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}
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buffers = calloc(req.count, sizeof(*buffers));
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if (!buffers) {
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fprintf(stderr, "Out of memory\n");
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exit(EXIT_FAILURE);
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}
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for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
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struct v4l2_buffer buf;
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memset(&buf, 0, sizeof(buf));
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buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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buf.memory = V4L2_MEMORY_MMAP;
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buf.index = n_buffers;
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if (-1 == xioctl(fd, VIDIOC_QUERYBUF, &buf))
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errno_exit("VIDIOC_QUERYBUF");
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buffers[n_buffers].length = buf.length;
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buffers[n_buffers].start =
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mmap(NULL /* start anywhere */,
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buf.length,
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PROT_READ | PROT_WRITE /* required */,
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MAP_SHARED /* recommended */,
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fd, buf.m.offset);
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if (MAP_FAILED == buffers[n_buffers].start)
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errno_exit("mmap");
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}
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}
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static void init_userp(unsigned int buffer_size)
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{
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struct v4l2_requestbuffers req;
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memset(&req, 0, sizeof(req));
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req.count = 4;
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req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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req.memory = V4L2_MEMORY_USERPTR;
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if (-1 == xioctl(fd, VIDIOC_REQBUFS, &req)) {
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if (EINVAL == errno) {
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fprintf(stderr, "%s does not support "
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"user pointer i/o\n", dev_name);
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exit(EXIT_FAILURE);
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} else {
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errno_exit("VIDIOC_REQBUFS");
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}
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}
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buffers = calloc(4, sizeof(*buffers));
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if (!buffers) {
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fprintf(stderr, "Out of memory\n");
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exit(EXIT_FAILURE);
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}
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for (n_buffers = 0; n_buffers < 4; ++n_buffers) {
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buffers[n_buffers].length = buffer_size;
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buffers[n_buffers].start = malloc(buffer_size);
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if (!buffers[n_buffers].start) {
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fprintf(stderr, "Out of memory\n");
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exit(EXIT_FAILURE);
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}
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}
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}
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/* --------------------------------------------------------------------- */
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int init_device(int notused)
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{
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struct v4l2_capability cap;
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struct v4l2_cropcap cropcap;
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struct v4l2_crop crop;
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struct v4l2_format fmt;
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unsigned int min;
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#if DEBUG_LEVEL
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fprintf(stderr, ">>> %s ( %d )\n", __func__, notused);
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#endif
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if (-1 == xioctl(fd, VIDIOC_QUERYCAP, &cap)) {
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if (EINVAL == errno) {
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fprintf(stderr, "%s is not a V4L2 device\n", dev_name);
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exit(EXIT_FAILURE);
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}
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else {
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errno_exit("VIDIOC_QUERYCAP");
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}
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}
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if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
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fprintf(stderr, "%s is no video capture device\n", dev_name);
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exit(EXIT_FAILURE);
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}
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switch (io) {
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case IO_METHOD_READ:
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if (!(cap.capabilities & V4L2_CAP_READWRITE)) {
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fprintf(stderr, "%s do not support read i/o\n", dev_name);
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exit(EXIT_FAILURE);
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}
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if (verbosity) fprintf(stderr, "%s io method read OK\n", __func__);
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break;
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case IO_METHOD_MMAP:
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case IO_METHOD_USERPTR:
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if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
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fprintf(stderr, "%s do not support streaming i/o\n", dev_name);
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exit(EXIT_FAILURE);
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}
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if (verbosity) fprintf(stderr, "%s io mmap/userptr OK\n", __func__);
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break;
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} /* end switch */
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/* Select video input, video standard and tune here. */
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memset(&cropcap, 0, sizeof(cropcap));
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cropcap.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (0 == xioctl(fd, VIDIOC_CROPCAP, &cropcap)) {
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crop.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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crop.c = cropcap.defrect; /* reset to default */
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if (-1 == xioctl(fd, VIDIOC_S_CROP, &crop)) {
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switch (errno) {
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case EINVAL:
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/* Cropping not supported. */
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break;
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default:
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/* Errors ignored. */
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break;
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}
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}
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} else {
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/* Errors ignored. */
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}
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memset(&fmt, 0, sizeof(fmt)); // CLEAR(fmt);
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fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
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if (force_format) {
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fmt.fmt.pix.width = 640;
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fmt.fmt.pix.height = 480;
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fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_YUYV;
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fmt.fmt.pix.field = V4L2_FIELD_INTERLACED;
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if (-1 == xioctl(fd, VIDIOC_S_FMT, &fmt))
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errno_exit("VIDIOC_S_FMT");
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/* Note VIDIOC_S_FMT may change width and height. */
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} else {
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/* Preserve original settings as set by v4l2-ctl for example */
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if (-1 == xioctl(fd, VIDIOC_G_FMT, &fmt))
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errno_exit("VIDIOC_G_FMT");
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}
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/* Buggy driver paranoia. */
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min = fmt.fmt.pix.width * 2;
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if (fmt.fmt.pix.bytesperline < min)
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fmt.fmt.pix.bytesperline = min;
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min = fmt.fmt.pix.bytesperline * fmt.fmt.pix.height;
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if (fmt.fmt.pix.sizeimage < min)
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fmt.fmt.pix.sizeimage = min;
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switch (io) {
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case IO_METHOD_READ:
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init_read(fmt.fmt.pix.sizeimage);
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break;
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case IO_METHOD_MMAP:
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init_mmap();
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break;
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case IO_METHOD_USERPTR:
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init_userp(fmt.fmt.pix.sizeimage);
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break;
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}
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return 0;
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}
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