take_pictures_contrib.c

/* V4L2 video picture grabber
   Copyright (C) 2009 Mauro Carvalho Chehab <mchehab@infradead.org>

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
 */

/*
Convert camera to a few ppms.
Adapted from official git tree: https://git.linuxtv.org/v4l-utils.git v4l-utils-1.10.0 contrib/test/v4l2grab.c
*/

#define _XOPEN_SOURCE 700
#include <argp.h>
#include <errno.h>
#include <fcntl.h>
#include <libv4l2.h>
#include <linux/videodev2.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/time.h>
#include <sys/types.h>
#include <time.h>

#define CLEAR_P(x,s) memset((x), 0, s)
#define CLEAR(x) CLEAR_P(&(x), sizeof(x))

struct buffer {
    void   *start;
    size_t length;
};

static void xioctl(int fh, unsigned long int request, void *arg)
{
    int r;
    do {
        r = v4l2_ioctl(fh, request, arg);
    } while (r == -1 && ((errno == EINTR) || (errno == EAGAIN)));
    if (r == -1) {
        fprintf(stderr, "%s(%lu): error %d, %s\n", __func__,
            _IOC_NR(request), errno, strerror(errno));
        exit(EXIT_FAILURE);
    }
}

/* Used by the multi thread capture version */
struct buffer_queue {
    struct v4l2_buffer *buffers;
    int buffers_size;

    int read_pos;
    int write_pos;
    int n_frames;

    int fd;

    pthread_mutex_t mutex;
    pthread_cond_t buffer_cond;
};

/* Gets a buffer and puts it in the buffers list at write position, then
 * notifies the consumer that a new buffer is ready to be used */
static void *produce_buffer (void * p)
{
    struct buffer_queue         *bq;
    fd_set              fds;
    struct timeval          tv;
    int             i;
    struct v4l2_buffer      *buf;
    int             r;

    bq = p;

    for (i = 0; i < bq->n_frames; i++) {
        printf ("Prod: %d\n", i);
        buf = &bq->buffers[bq->write_pos % bq->buffers_size];
        do {
            FD_ZERO(&fds);
            FD_SET(bq->fd, &fds);

            /* Timeout. */
            tv.tv_sec = 2;
            tv.tv_usec = 0;

            r = select(bq->fd + 1, &fds, NULL, NULL, &tv);
        } while ((r == -1 && (errno == EINTR)));
        if (r == -1) {
            perror("select");
            pthread_exit (NULL);
            return NULL;
        }

        CLEAR_P(buf, sizeof(struct v4l2_buffer));
        buf->type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf->memory = V4L2_MEMORY_MMAP;
        xioctl(bq->fd, VIDIOC_DQBUF, buf);

        pthread_mutex_lock (&bq->mutex);
        bq->write_pos++;
        printf ("Prod: %d (done)\n", i);
        pthread_cond_signal (&bq->buffer_cond);
        pthread_mutex_unlock (&bq->mutex);

    }

    pthread_exit (NULL);
}

/* will create a separate thread that will produce the buffers and put
 * into a circular array while this same thread will get the buffers from
 * this array and 'render' them */
static int capture_threads (int fd, struct buffer *buffers, int bufpool_size,
            struct v4l2_format fmt, int n_frames,
            char *out_dir, int sleep_ms)
{
    struct v4l2_buffer      buf;
    unsigned int            i;
    struct buffer_queue     buf_queue;
    pthread_t           producer;
    char                out_name[25 + strlen(out_dir)];
    FILE                *fout;
    struct timespec         sleeptime;

    if (sleep_ms) {
        sleeptime.tv_sec = sleep_ms / 1000;
        sleeptime.tv_nsec = (sleep_ms % 1000) * 1000000;
    }

    buf_queue.buffers_size = bufpool_size * 2;
    buf_queue.buffers = calloc(buf_queue.buffers_size,
                   sizeof(struct v4l2_buffer));
    buf_queue.fd = fd;
    buf_queue.read_pos = 0;
    buf_queue.write_pos = 0;
    buf_queue.n_frames = n_frames;
    pthread_mutex_init (&buf_queue.mutex, NULL);
    pthread_cond_init (&buf_queue.buffer_cond, NULL);

    pthread_create (&producer, NULL, produce_buffer, &buf_queue);

    for (i = 0; i < n_frames; i++) {
        printf ("Read: %d\n", i);

        /* wait for a buffer to be available in the queue */
        pthread_mutex_lock (&buf_queue.mutex);
        while (buf_queue.read_pos == buf_queue.write_pos) {
            pthread_cond_wait (&buf_queue.buffer_cond,
                       &buf_queue.mutex);
        }
        pthread_mutex_unlock (&buf_queue.mutex);

        if (sleep_ms)
            nanosleep (&sleeptime, NULL);

        sprintf(out_name, "%s/out%03d.ppm", out_dir, i);
        fout = fopen(out_name, "w");
        if (!fout) {
            perror("Cannot open image");
            exit(EXIT_FAILURE);
        }
        fprintf(fout, "P6\n%d %d 255\n",
            fmt.fmt.pix.width, fmt.fmt.pix.height);
        buf = buf_queue.buffers[buf_queue.read_pos %
                    buf_queue.buffers_size];
        fwrite(buffers[buf.index].start, buf.bytesused, 1, fout);
        fclose(fout);

        xioctl(fd, VIDIOC_QBUF, &buf);

        pthread_mutex_lock (&buf_queue.mutex);
        buf_queue.read_pos++;
        printf ("Read: %d (done)\n", i);
        pthread_cond_signal (&buf_queue.buffer_cond);
        pthread_mutex_unlock (&buf_queue.mutex);
    }

    pthread_mutex_destroy (&buf_queue.mutex);
    pthread_cond_destroy (&buf_queue.buffer_cond);
    free (buf_queue.buffers);
    return 0;
}

static int capture_loop (int fd, struct buffer *buffers, struct v4l2_format fmt,
            int n_frames, char *out_dir)
{
    struct v4l2_buffer      buf;
    unsigned int            i;
    struct timeval          tv;
    int             r;
    fd_set              fds;
    FILE                *fout;
    char                out_name[25 + strlen(out_dir)];

    for (i = 0; i < n_frames; i++) {
        do {
            FD_ZERO(&fds);
            FD_SET(fd, &fds);

            /* Timeout. */
            tv.tv_sec = 2;
            tv.tv_usec = 0;

            r = select(fd + 1, &fds, NULL, NULL, &tv);
        } while ((r == -1 && (errno == EINTR)));
        if (r == -1) {
            perror("select");
            return errno;
        }

        CLEAR(buf);
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        xioctl(fd, VIDIOC_DQBUF, &buf);

        sprintf(out_name, "%s/out%03d.ppm", out_dir, i);
        fout = fopen(out_name, "w");
        if (!fout) {
            perror("Cannot open image");
            exit(EXIT_FAILURE);
        }
        fprintf(fout, "P6\n%d %d 255\n",
            fmt.fmt.pix.width, fmt.fmt.pix.height);
        fwrite(buffers[buf.index].start, buf.bytesused, 1, fout);
        fclose(fout);

        xioctl(fd, VIDIOC_QBUF, &buf);
    }
    return 0;
}

static int capture(char *dev_name, int x_res, int y_res, int n_frames,
           char *out_dir, int block, int threads, int sleep_ms)
{
    struct v4l2_format      fmt;
    struct v4l2_buffer      buf;
    struct v4l2_requestbuffers  req;
    enum v4l2_buf_type      type;
    int             fd = -1;
    unsigned int            i, n_buffers;
    struct buffer           *buffers;

    if (block)
        fd = v4l2_open(dev_name, O_RDWR, 0);
    else
        fd = v4l2_open(dev_name, O_RDWR | O_NONBLOCK, 0);
    if (fd < 0) {
        perror("Cannot open device");
        exit(EXIT_FAILURE);
    }

    CLEAR(fmt);
    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    fmt.fmt.pix.width       = x_res;
    fmt.fmt.pix.height      = y_res;
    fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_RGB24;
    fmt.fmt.pix.field       = V4L2_FIELD_INTERLACED;
    xioctl(fd, VIDIOC_S_FMT, &fmt);
    if (fmt.fmt.pix.pixelformat != V4L2_PIX_FMT_RGB24) {
        printf("Libv4l didn't accept RGB24 format. Can't proceed.\n");
        exit(EXIT_FAILURE);
    }
    if ((fmt.fmt.pix.width != x_res) || (fmt.fmt.pix.height != y_res))
        printf("Warning: driver is sending image at %dx%d\n",
            fmt.fmt.pix.width, fmt.fmt.pix.height);

    CLEAR(req);
    req.count = 2;
    req.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    req.memory = V4L2_MEMORY_MMAP;
    xioctl(fd, VIDIOC_REQBUFS, &req);

    buffers = calloc(req.count, sizeof(*buffers));
    for (n_buffers = 0; n_buffers < req.count; ++n_buffers) {
        CLEAR(buf);

        buf.type        = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory      = V4L2_MEMORY_MMAP;
        buf.index       = n_buffers;

        xioctl(fd, VIDIOC_QUERYBUF, &buf);

        buffers[n_buffers].length = buf.length;
        buffers[n_buffers].start = v4l2_mmap(NULL, buf.length,
                  PROT_READ | PROT_WRITE, MAP_SHARED,
                  fd, buf.m.offset);

        if (MAP_FAILED == buffers[n_buffers].start) {
            perror("mmap");
            exit(EXIT_FAILURE);
        }
    }

    for (i = 0; i < n_buffers; ++i) {
        CLEAR(buf);
        buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
        buf.memory = V4L2_MEMORY_MMAP;
        buf.index = i;
        xioctl(fd, VIDIOC_QBUF, &buf);
    }
    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;

    xioctl(fd, VIDIOC_STREAMON, &type);
    if (threads)
        capture_threads(fd, buffers, 2, fmt, n_frames, out_dir,
                sleep_ms);
    else
        capture_loop(fd, buffers, fmt, n_frames, out_dir);

    type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
    xioctl(fd, VIDIOC_STREAMOFF, &type);
    for (i = 0; i < n_buffers; ++i)
        v4l2_munmap(buffers[i].start, buffers[i].length);
    v4l2_close(fd);

    return 0;
}

static const char doc[] = "\nCapture images using libv4l, storing them as ppm files\n";

static const struct argp_option options[] = {
    {"device",  'd',    "DEV",      0,  "video device (default: /dev/video0)", 0},
    {"out-dir", 'o',    "OUTDIR",   0,  "output directory (default: current dir)", 0},
    {"xres",    'x',    "XRES",     0,  "horizontal resolution", 0},
    {"yres",    'y',    "YRES",     0,  "vertical resolution", 0},
    {"n-frames",    'n',    "NFRAMES",  0,  "number of frames to capture", 0},
    {"thread-enable", 't',  "THREADS",  0,  "if different threads should capture and save", 0},
    {"blockmode-enable", 'b', "BLOCKMODE",  0,  "if blocking mode should be used", 0},
    {"sleep-time",  's',    "SLEEP",    0,  "how long should the consumer thread sleep to simulate the processing of a buffer (in ms)"},
    { 0, 0, 0, 0, 0, 0 }
};

/* Static vars to store the parameters */
static char     *dev_name = "/dev/video0";
static char *out_dir = ".";
static int  x_res = 640;
static int  y_res = 480;
static int  n_frames = 20;
static int  threads = 0;
static int  block = 0;
static int  sleep_ms = 0;

static error_t parse_opt(int k, char *arg, struct argp_state *state)
{
    int val;

    switch (k) {
    case 'd':
        dev_name = arg;
        break;
    case 'o':
        out_dir = arg;
        break;
    case 'x':
        val = atoi(arg);
        if (val)
            x_res = val;
        break;
    case 'y':
        val = atoi(arg);
        if (val)
            y_res = val;
        break;
    case 'n':
        val = atoi(arg);
        if (val)
            n_frames = val;
        break;
    case 't':
        threads = 1;
        break;
    case 'b':
        block = 1;
        break;
    case 's':
        val = atoi(arg);
        if (val)
            sleep_ms = val;
        break;
    default:
        return ARGP_ERR_UNKNOWN;
    }
    return 0;
}

static struct argp argp = {
    .options = options,
    .parser = parse_opt,
    .doc = doc,
};


int main(int argc, char **argv)
{
    argp_parse(&argp, argc, argv, 0, 0, 0);

    return capture(dev_name, x_res, y_res, n_frames, out_dir, block,
               threads, sleep_ms);
}