wip video device

src/video.c

@@ -0,0 +1,207 @@
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/videodev2.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#include "logs.h"
+#include "types.h"
+#include "video.h"
+
+static VideoDevice open_device(char *name) {
+  VideoDevice device;
+
+  device.name = name;
+  device.error = false;
+  device.fd = -1;
+
+  device.fd = open(name, O_RDWR);
+  if (device.fd == -1) {
+    log_warn("(%s) Cannot open device", name);
+    device.error = true;
+  }
+
+  return device;
+}
+
+static bool check_device_caps(VideoDevice *device) {
+  struct v4l2_capability cap;
+
+  memset(&cap, 0, sizeof(cap));
+
+  if (ioctl(device->fd, VIDIOC_QUERYCAP, &cap) == -1) {
+    if (EINVAL == errno) {
+      log_warn("(%s) Not a V4L2 device", device->name);
+    } else {
+      log_error("(%s) VIDIOC_QUERYCAP unkown error", device->name);
+    }
+    device->error = true;
+    return false;
+  }
+
+  if (!(cap.capabilities & V4L2_CAP_VIDEO_CAPTURE)) {
+    log_warn("(%s) Not a video capture device", device->name);
+    device->error = true;
+    return false;
+  }
+
+  if (!(cap.capabilities & V4L2_CAP_STREAMING)) {
+    log_warn("(%s) No streaming i/o support", device->name);
+    device->error = true;
+    return false;
+  }
+
+  return true;
+}
+
+static bool set_device_format(VideoDevice *device, unsigned int preferred_width,
+                              unsigned int preferred_height) {
+  struct v4l2_format fmt;
+
+  memset(&fmt, 0, sizeof(fmt));
+
+  fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+  fmt.fmt.pix.width = preferred_width;
+  fmt.fmt.pix.height = preferred_height;
+  fmt.fmt.pix.pixelformat = V4L2_PIX_FMT_BGRX32;
+  fmt.fmt.pix.field = V4L2_FIELD_NONE;
+
+  if (ioctl(device->fd, VIDIOC_S_FMT, &fmt) == -1) {
+    log_warn("(%s) Format set failed", device->name);
+    device->error = true;
+    return false;
+  }
+
+  device->width = fmt.fmt.pix.width;
+  device->height = fmt.fmt.pix.height;
+  device->pixelformat = fmt.fmt.pix.pixelformat;
+  device->bytesperline = fmt.fmt.pix.bytesperline;
+
+  log_info("(%s) Format fourcc:  %c%c%c%c", device->name,
+           fmt.fmt.pix.pixelformat, fmt.fmt.pix.pixelformat >> 8,
+           fmt.fmt.pix.pixelformat >> 16, fmt.fmt.pix.pixelformat >> 24);
+  log_info("(%s) Resolution:  %dx%d", device->name, fmt.fmt.pix.width,
+           fmt.fmt.pix.height);
+
+  return true;
+}
+
+static bool request_buffers(VideoDevice *device) {
+  struct v4l2_requestbuffers reqbuf;
+
+  memset(&reqbuf, 0, sizeof(reqbuf));
+
+  reqbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+  reqbuf.memory = V4L2_MEMORY_MMAP;
+  reqbuf.count = 1;
+
+  if (ioctl(device->fd, VIDIOC_REQBUFS, &reqbuf) == -1) {
+    if (errno == EINVAL) {
+      log_info("(%s) Video capturing or DMABUF streaming is not supported",
+               device->name);
+    } else {
+      log_error("(%s) VIDIOC_REQBUFS unkown error", device->name);
+    }
+    device->error = true;
+    return false;
+  }
+
+  log_info("(%s) V4L2 Buffer Count:  %d", device->name, reqbuf.count);
+
+  return true;
+}
+
+static bool export_buffer(VideoDevice *device) {
+  struct v4l2_exportbuffer expbuf;
+
+  device->exp_fd = -1;
+
+  memset(&expbuf, 0, sizeof(expbuf));
+
+  expbuf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+  expbuf.index = 0; /// '0' for one buffer
+  expbuf.flags = O_RDONLY;
+
+  if (ioctl(device->fd, VIDIOC_EXPBUF, &expbuf) == -1) {
+    log_error("(%s) VIDIOC_EXPBUF error", device->name);
+    device->error = true;
+    return false;
+  }
+
+  device->exp_fd = expbuf.fd;
+
+  return true;
+}
+
+static const enum v4l2_buf_type buf_type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+
+static bool open_stream(VideoDevice *device) {
+  if (ioctl(device->fd, VIDIOC_STREAMON, &buf_type) == -1) {
+    log_error("(%s) VIDIOC_STREAMON error", device->name);
+    device->error = true;
+    return false;
+  }
+
+  return true;
+}
+
+static void create_image_buffer(VideoDevice *device) {
+  memset(&device->buf, 0, sizeof(device->buf));
+
+  device->buf.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+  device->buf.memory = V4L2_MEMORY_MMAP;
+  device->buf.index = 0;
+
+  ioctl(device->fd, VIDIOC_QBUF, &device->buf);
+}
+
+static void close_stream(VideoDevice device) {
+  ioctl(device.fd, VIDIOC_STREAMOFF, &buf_type);
+}
+
+VideoDevice video_init(char *name, unsigned int preferred_width,
+                       unsigned int preferred_height) {
+  VideoDevice device;
+
+  device = open_device(name);
+
+  if (device.error) {
+    return device;
+  }
+
+  if (!check_device_caps(&device)) {
+    return device;
+  }
+
+  if (!set_device_format(&device, preferred_width, preferred_height)) {
+    return device;
+  }
+
+  if (!request_buffers(&device)) {
+    return device;
+  }
+
+  if (!export_buffer(&device)) {
+    return device;
+  }
+
+  if (!open_stream(&device)) {
+    return device;
+  }
+
+  create_image_buffer(&device);
+
+  return device;
+}
+
+void video_read(VideoDevice device) {
+  ioctl(device.fd, VIDIOC_DQBUF, &device.buf);
+  ioctl(device.fd, VIDIOC_QBUF, &device.buf);
+  // TODO check for error and close
+}
+
+void video_free(VideoDevice device) {
+  close_stream(device);
+  close(device.exp_fd);
+  close(device.fd);
+}