Add a switch to print video latency.

[nageru] / print_latency.h

diff --git a/print_latency.h b/print_latency.h
new file mode 100644 (file)
index 0000000..9d8a93b
--- /dev/null
+++ b/print_latency.h
@@ -0,0 +1,21 @@
+#ifndef _PRINT_LATENCY_H
+#define _PRINT_LATENCY_H 1
+
+// A small utility function to print the latency between two end points
+// (typically when the frame was received from the video card, and some
+// point when the frame is ready to be output in some form).
+
+#include <chrono>
+#include <string>
+
+// Since every output frame is based on multiple input frames, we need
+// more than one start timestamp. For now, we keep just the smallest
+// and largest timestamp, so that we can print out a range.
+// For both of these, steady_clock::time_point::min() is used for “not set”.
+struct ReceivedTimestamps {
+       std::chrono::steady_clock::time_point min_ts, max_ts;
+};
+
+void print_latency(const std::string &header, const ReceivedTimestamps &received_ts, bool is_b_frame, int *frameno);
+
+#endif  // !defined(_PRINT_LATENCY_H)