obfp += 2;
};
*obfp = 0;
-
-
+
+
// get raw timestamp information
// I think that a good way to understand these timestamps is that
// (1) the rtlt below is the timestamp of the frame that should be playing at the
// Thus, (3) the latency can be calculated by subtracting the second from the
// first.
// There must be more to it -- there something missing.
-
+
// In addition, it seems that if the value of the short represented by the second
// pair of bytes in the packet is 7
// then an extra time lag is expected to be added, presumably by
// the AirPort Express.
-
+
// Best guess is that this delay is 11,025 frames.
-
+
uint32_t rtlt = nctohl(&packet[4]); // raw timestamp less latency
uint32_t rt = nctohl(&packet[16]); // raw timestamp
-
+
uint32_t fl = nctohs(&packet[2]); //
-
+
debug(1,"Sync Packet of %d bytes received: \"%s\", flags: %d, timestamps %u and %u,
giving a latency of %d frames.",plen,obf,fl,rt,rtlt,rt-rtlt);
//debug(1,"Monotonic timestamps are: %" PRId64 " and %" PRId64 "
if ((flags == 7) || ((conn->AirPlayVersion > 0) && (conn->AirPlayVersion <= 353)) ||
((conn->AirPlayVersion > 0) && (conn->AirPlayVersion >= 371))) {
la += config.fixedLatencyOffset;
- // debug(1, "Latency offset by %" PRIu32" frames due to the source flags and version giving a latency of %" PRIu32 " frames.", config.fixedLatencyOffset, la);
+ // debug(1, "Latency offset by %" PRIu32" frames due to the source flags and version
+ // giving a latency of %" PRIu32 " frames.", config.fixedLatencyOffset, la);
}
if ((conn->maximum_latency) && (conn->maximum_latency < la))
la = conn->maximum_latency;
int32_t latency_offset =
(int32_t)(config.audio_backend_latency_offset * conn->input_rate);
- // debug(1,"latency offset is %" PRId32 ", input rate is %u", latency_offset, conn->input_rate);
+ // debug(1,"latency offset is %" PRId32 ", input rate is %u", latency_offset,
+ // conn->input_rate);
int32_t adjusted_latency = latency_offset + (int32_t)la;
if ((adjusted_latency < 0) ||
(adjusted_latency >
", minimum latency: %" PRIu32 ", maximum "
"latency: %" PRIu32 ", fixed offset: %" PRIu32
", audio_backend_latency_offset: %f.",
- conn->latency, sync_rtp_timestamp - rtp_timestamp_less_latency, conn->minimum_latency,
- conn->maximum_latency, config.fixedLatencyOffset,
+ conn->latency, sync_rtp_timestamp - rtp_timestamp_less_latency,
+ conn->minimum_latency, conn->maximum_latency, config.fixedLatencyOffset,
config.audio_backend_latency_offset);
}
}