diff options
| -rw-r--r-- | src/DabMultiplexer.cpp | 27 |
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 |