Add timestamps on each received frame.

[bmusb] / bmusb / bmusb.h

diff --git a/bmusb/bmusb.h b/bmusb/bmusb.h
index 506685dc4c6a7401d17143cdb611315981c7b187..6aabd51fcc39f68c1b0780e24d5451319083b317 100644 (file)
--- a/bmusb/bmusb.h
+++ b/bmusb/bmusb.h
@@ -4,6 +4,7 @@
 #include <libusb.h>
 #include <stdint.h>
 #include <atomic>
+#include <chrono>
 #include <condition_variable>
 #include <deque>
 #include <functional>
@@ -39,6 +40,14 @@ class FrameAllocator {
                // If so, <len> and <size> are still about the number of total bytes
                // so if size == 1024, there's 512 bytes in data and 512 in data2.
                bool interleaved = false;
+
+               // At what point this frame was received. Note that this marks the
+               // _end_ of the frame being received, not the beginning.
+               // Thus, if you want to measure latency, you'll also need to include
+               // the time the frame actually took to transfer (usually 1/fps,
+               // ie., the frames are typically transferred in real time).
+               std::chrono::steady_clock::time_point received_timestamp =
+                       std::chrono::steady_clock::time_point::min();
        };
 
        virtual ~FrameAllocator();
@@ -175,6 +184,10 @@ class BMUSBCapture : public CaptureInterface {
 
        ~BMUSBCapture() {}
 
+       // Note: Cards could be unplugged and replugged between this call and
+       // actually opening the card (in configure_card()).
+       static unsigned num_cards();
+
        std::map<uint32_t, VideoMode> get_available_video_modes() const override;
        uint32_t get_current_video_mode() const override;
        void set_video_mode(uint32_t video_mode_id) override;
@@ -251,9 +264,11 @@ class BMUSBCapture : public CaptureInterface {
        // The callback function transfers ownership. If you don't want to hold
        // on to the device given to you in the callback, you need to call
        // libusb_unref_device().
-       static void set_card_connected_callback(card_connected_callback_t callback)
+       static void set_card_connected_callback(card_connected_callback_t callback,
+                                               bool hotplug_existing_devices_arg = false)
        {
                card_connected_callback = callback;
+               hotplug_existing_devices = hotplug_existing_devices_arg;
        }
 
        // Similar to set_card_connected_callback(), with the same caveats.
@@ -299,6 +314,7 @@ class BMUSBCapture : public CaptureInterface {
        std::unique_ptr<FrameAllocator> owned_audio_frame_allocator;
        frame_callback_t frame_callback = nullptr;
        static card_connected_callback_t card_connected_callback;
+       static bool hotplug_existing_devices;
        card_disconnected_callback_t card_disconnected_callback = nullptr;
 
        std::thread dequeue_thread;