Add missing file timebase.h.

diff --git a/timebase.h b/timebase.h
new file mode 100644 (file)
index 0000000..be2362b
--- /dev/null
+++ b/timebase.h
@@ -0,0 +1,17 @@
+#ifndef _TIMEBASE_H
+#define _TIMEBASE_H 1
+
+// Common timebase that allows us to represent one frame exactly in all the
+// relevant frame rates:
+//
+//   Timebase:              1/60000
+//   Frame at 50fps:     1200/60000
+//   Frame at 60fps:     1000/60000
+//   Frame at 59.94fps:  1001/60000
+//
+// If we also wanted to represent one sample at 48000 Hz, we'd need
+// to go to 300000. Also supporting one sample at 44100 Hz would mean
+// going to 44100000; probably a bit excessive.
+#define TIMEBASE 60000
+
+#endif  // !defined(_TIMEBASE_H)