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-rw-r--r--src/DabMultiplexer.cpp27
1 files changed, 13 insertions, 14 deletions
diff --git a/src/DabMultiplexer.cpp b/src/DabMultiplexer.cpp
index 9bd3c3f..2bd8d74 100644
--- a/src/DabMultiplexer.cpp
+++ b/src/DabMultiplexer.cpp
@@ -134,24 +134,23 @@ void DabMultiplexer::prepare(bool require_tai_clock)
throw MuxInitException();
}
- /* TODO:
- * In a SFN, when reconfiguring the ensemble, the multiplexer
- * has to be restarted (odr-dabmux doesn't support reconfiguration).
- * Ideally, we must be able to restart transmission s.t. the receiver
- * synchronisation is preserved.
+ /* Ensure edi_time and TIST represent current time. Keep
+ * a granularity of 24ms, which corresponds to the
+ * duration of an ETI frame, to get nicer timestamps.
*/
using Sec = chrono::seconds;
- const auto now = chrono::time_point_cast<Sec>(chrono::system_clock::now());
-
- edi_time = chrono::system_clock::to_time_t(now);
-
- // We define that when the time is multiple of six seconds, the timestamp
- // (PPS offset) is 0. This ensures consistency of TIST even across a
- // mux restart
+ const auto now = chrono::system_clock::now();
+ edi_time = chrono::system_clock::to_time_t(chrono::time_point_cast<Sec>(now));
+ auto offset = now - chrono::time_point_cast<Sec>(now);
+ if (offset >= chrono::seconds(1)) {
+ throw std::logic_error("Invalid startup offset calculation for TIST! " +
+ to_string(chrono::duration_cast<chrono::milliseconds>(offset).count()) +
+ " ms");
+ }
timestamp = 0;
- edi_time -= (edi_time % 6);
- while (edi_time < chrono::system_clock::to_time_t(now)) {
+ while (offset >= chrono::milliseconds(24)) {
increment_timestamp();
+ offset -= chrono::milliseconds(24);
}
// Try to load offset once