v4l2_common.h

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 /*
 * Copyright (c) 2012-2024 CESNET
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 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
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 *
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 * EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#ifndef V4L2_COMMON_4B01337E_4F0D_48EC_91A7_D220AD919D3B
#define V4L2_COMMON_4B01337E_4F0D_48EC_91A7_D220AD919D3B
 
#include <linux/videodev2.h>
#include <stdint.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
 
#include "types.h"
 
#define V4L2_PROBE_MAX 64
 
static struct {
        enum v4l2_field v4l_f;
        enum interlacing_t ug_f;
} v4l2_field_map [] = {
        { V4L2_FIELD_NONE, PROGRESSIVE },
        { V4L2_FIELD_SEQ_TB, UPPER_FIELD_FIRST },
        { V4L2_FIELD_SEQ_BT, LOWER_FIELD_FIRST },
        { V4L2_FIELD_INTERLACED, INTERLACED_MERGED },
};
 
static struct {
        uint32_t v4l2_fcc;
        codec_t ug_codec;
} v4l2_ug_map[] = {
        {V4L2_PIX_FMT_YUYV, YUYV},
        {V4L2_PIX_FMT_UYVY, UYVY},
        {V4L2_PIX_FMT_YUV420, I420},
#ifdef V4L2_PIX_FMT_YUVA32
        {V4L2_PIX_FMT_YUVA32, Y416},
#endif
#ifdef V4L2_PIX_FMT_Y210
        {V4L2_PIX_FMT_Y210, Y216},
#endif
#ifdef V4L2_PIX_FMT_Y212
        {V4L2_PIX_FMT_Y212, Y216},
#endif
#ifdef V4L2_PIX_FMT_Y216
        {V4L2_PIX_FMT_Y216, Y216},
#endif
        {V4L2_PIX_FMT_RGB24, RGB},
        {V4L2_PIX_FMT_BGR24, BGR},
        {V4L2_PIX_FMT_RGB32, RGBA},
#ifdef V4L2_PIX_FMT_RGBA32
        {V4L2_PIX_FMT_RGBA32, RGBA},
#endif
#ifdef V4L2_PIX_FMT_RGBX32
        {V4L2_PIX_FMT_RGBX32, RGBA},
#endif
#ifdef V4L2_PIX_FMT_RGBX1010102
        {V4L2_PIX_FMT_RGBX1010102, R10k},
#endif
#ifdef V4L2_PIX_FMT_RGBA1010102
        {V4L2_PIX_FMT_RGBA1010102, R10k},
#endif
        {V4L2_PIX_FMT_MJPEG, MJPG},
        {V4L2_PIX_FMT_JPEG, MJPG},
        {V4L2_PIX_FMT_H264, H264},
        //{V4L2_PIX_FMT_H264_NO_SC, H264}, ///< H.264 without tart codes, @todo implement adding start codes (capture)
#ifdef V4L2_PIX_FMT_HEVC
        {V4L2_PIX_FMT_HEVC, H265},
#endif
#ifdef V4L2_PIX_FMT_HEVC
        {V4L2_PIX_FMT_VP9, VP9},
#endif
};
 
struct v4l2_buffer_data {
        void *start;
        size_t length;
};
 
static _Bool set_v4l2_buffers(int fd, struct v4l2_requestbuffers *reqbuf, struct v4l2_buffer_data *buffers) {
        if (ioctl (fd, VIDIOC_REQBUFS, reqbuf) != 0) {
                if (errno == EINVAL)
                        log_msg(LOG_LEVEL_ERROR, MOD_NAME "Video capturing or mmap-streaming is not supported\n");
                else
                        log_perror(LOG_LEVEL_ERROR, MOD_NAME "VIDIOC_REQBUFS");
                return 0;
 
        }
 
        if (reqbuf->count < 2) {
                /* You may need to free the buffers here. */
                log_msg(LOG_LEVEL_ERROR, MOD_NAME "Not enough buffer memory\n");
                return 0;
        }
 
        for (unsigned int i = 0; i < reqbuf->count; i++) {
                struct v4l2_buffer buf;
                memset(&buf, 0, sizeof(buf));
                buf.type = reqbuf->type;
                buf.memory = V4L2_MEMORY_MMAP;
                buf.index = i;
 
                if (-1 == ioctl (fd, VIDIOC_QUERYBUF, &buf)) {
                        log_perror(LOG_LEVEL_ERROR, MOD_NAME "VIDIOC_QUERYBUF");
                        return 0;
                }
 
                buffers[i].length = buf.length; /* remember for munmap() */
 
                buffers[i].start = mmap(NULL, buf.length,
                                PROT_READ | PROT_WRITE, /* recommended */
                                MAP_SHARED,             /* recommended */
                                fd, buf.m.offset);
 
                if (MAP_FAILED == buffers[i].start) {
                        /* If you do not exit here you should unmap() and free()
                           the buffers mapped so far. */
                        log_perror(LOG_LEVEL_ERROR, MOD_NAME "mmap");
                        return 0;
                }
 
                buf.flags = 0;
 
                if(ioctl(fd, VIDIOC_QBUF, &buf) != 0) {
                        log_perror(LOG_LEVEL_ERROR, MOD_NAME "Unable to enqueue buffer");
                        return 0;
                }
        }
        return 1;
}
 
static int try_open_v4l2_device(int log_level, const char *dev_name, int cap) {
        log_msg(LOG_LEVEL_VERBOSE, "Trying device: %s\n", dev_name);
        int fd = open(dev_name, O_RDWR);
        if (fd == -1) {
                char errbuf[1024];
                log_msg(log_level, MOD_NAME "Unable to open input device %s: %s\n",
                                dev_name, strerror_r(errno, errbuf, sizeof errbuf));
                return -1;
        }
 
        struct v4l2_capability capability;
        memset(&capability, 0, sizeof(capability));
        if (ioctl(fd, VIDIOC_QUERYCAP, &capability) != 0) {
                log_perror(log_level, MOD_NAME "ioctl VIDIOC_QUERYCAP");
                close(fd);
                return -1;
        }
 
        if (!(capability.device_caps & cap)) {
                const char *cap_str = cap == V4L2_CAP_VIDEO_CAPTURE ? "capture" : "playback";
                log_msg(log_level, MOD_NAME "%s, %s can't %s\n",capability.card,capability.bus_info, cap_str);
                close(fd);
                return -1;
        }
 
        if (!(capability.device_caps & V4L2_CAP_STREAMING)) {
                log_msg(log_level, MOD_NAME "Streaming capability not present.\n");
                close(fd);
                return -1;
        }
 
        int index = 0;
 
        if (ioctl(fd, VIDIOC_S_INPUT, &index) != 0) {
                log_perror(log_level, MOD_NAME "Could not enable input (VIDIOC_S_INPUT)");
                close(fd);
                return -1;
        }
 
        return fd;
}
 
#endif // defined V4L2_COMMON_4B01337E_4F0D_48EC_91A7_D220AD919D3B