Add support for V4L2 output.

[nageru] / nageru / v4l_output.h

diff --git a/nageru/v4l_output.h b/nageru/v4l_output.h
new file mode 100644 (file)
index 0000000..b7686f6
--- /dev/null
+++ b/nageru/v4l_output.h
@@ -0,0 +1,37 @@
+#ifndef _V4L_OUTPUT_H
+#define _V4L_OUTPUT_H 1
+
+// Video-only V4L2 output. The intended use-case is output into
+// v4l2loopback to get into videoconferencing or the likes:
+//
+//   sudo apt install v4l2loopback-dkms
+//   sudo modprobe v4l2loopback video_nr=2 card_label='Nageru loopback' exclusive_caps=1
+//   nageru --v4l2-output /dev/video2
+//
+// Start Nageru before any readers.
+//
+// Unlike DecklinkOutput, this output does not own the master clock;
+// it is entirely unsynchronized, and runs off of the normal master clock.
+// It comes in addition to any other output, and is not GUI-controlled.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <memory>
+
+class V4LOutput {
+public:
+       V4LOutput(const char *device_path, unsigned width, unsigned height);
+       ~V4LOutput();
+
+       // Expects NV12 data.
+       void send_frame(const uint8_t *data);
+
+private:
+       const unsigned width, height;
+       const size_t image_size_bytes;
+       std::unique_ptr<uint8_t[]> yuv420_buf;
+       int video_fd;
+};
+
+#endif  // !defined(_V4L_OUTPUT_H)