diff options
| -rw-r--r-- | libs/gst/net/gstptpclock.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/libs/gst/net/gstptpclock.c b/libs/gst/net/gstptpclock.c index 68e1a021f..4755f08c2 100644 --- a/libs/gst/net/gstptpclock.c +++ b/libs/gst/net/gstptpclock.c @@ -106,6 +106,13 @@ GST_DEBUG_CATEGORY_STATIC (ptp_debug); */ #define USE_ONLY_SYNC_WITH_DELAY 1 +/* Filter out delay measurements that are too far away from the median of the + * last delay measurements, currently those that are more than 2 times as big. + * This increases accuracy a lot on wifi. + */ +#define USE_MEDIAN_PRE_FILTERING 1 +#define MEDIAN_PRE_FILTERING_WINDOW 9 + /* How many updates should be skipped at maximum when using USE_MEASUREMENT_FILTERING */ #define MAX_SKIPPED_UPDATES 5 @@ -306,6 +313,9 @@ typedef struct GstClockTime last_delay_req, min_delay_req_interval; guint16 last_delay_req_seqnum; + GstClockTime last_path_delays[MEDIAN_PRE_FILTERING_WINDOW]; + gint last_path_delays_missing; + GQueue pending_syncs; GstClock *domain_clock; @@ -770,6 +780,7 @@ select_best_master_clock (PtpDomainData * domain, GstClockTime now) sizeof (PtpClockIdentity)); domain->mean_path_delay = 0; domain->last_delay_req = 0; + domain->last_path_delays_missing = 9; domain->min_delay_req_interval = 0; domain->sync_interval = 0; domain->last_ptp_sync_time = 0; @@ -834,6 +845,7 @@ handle_announce_message (PtpMessage * msg, GstClockTime receive_time) g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", clock_name, NULL); g_free (clock_name); g_queue_init (&domain->pending_syncs); + domain->last_path_delays_missing = 9; domain_data = g_list_prepend (domain_data, domain); g_mutex_lock (&domain_clocks_lock); @@ -1230,9 +1242,27 @@ out: } +#ifdef USE_MEDIAN_PRE_FILTERING +static gint +compare_clock_time (const GstClockTime * a, const GstClockTime * b) +{ + if (*a < *b) + return -1; + else if (*a > *b) + return 1; + return 0; +} +#endif + static gboolean update_mean_path_delay (PtpDomainData * domain, PtpPendingSync * sync) { +#ifdef USE_MEDIAN_PRE_FILTERING + GstClockTime last_path_delays[G_N_ELEMENTS (domain->last_path_delays)]; + GstClockTime median; + gint i; +#endif + GstClockTime mean_path_delay, delay_req_delay; gboolean ret; @@ -1243,6 +1273,37 @@ update_mean_path_delay (PtpDomainData * domain, PtpPendingSync * sync) (sync->correction_field_sync + sync->correction_field_delay + 32768) / 65536) / 2; +#ifdef USE_MEDIAN_PRE_FILTERING + for (i = 1; i < G_N_ELEMENTS (domain->last_path_delays); i++) + domain->last_path_delays[i - 1] = domain->last_path_delays[i]; + domain->last_path_delays[i - 1] = mean_path_delay; + + if (domain->last_path_delays_missing) { + domain->last_path_delays_missing--; + } else { + memcpy (&last_path_delays, &domain->last_path_delays, + sizeof (last_path_delays)); + g_qsort_with_data (&last_path_delays, + G_N_ELEMENTS (domain->last_path_delays), sizeof (GstClockTime), + (GCompareDataFunc) compare_clock_time, NULL); + + median = last_path_delays[G_N_ELEMENTS (last_path_delays) / 2]; + + /* FIXME: We might want to use something else here, like only allowing + * things in the interquartile range, or also filtering away delays that + * are too small compared to the median. This here worked well enough + * in tests so far. + */ + if (mean_path_delay > 2 * median) { + GST_WARNING ("Path delay for domain %u too big compared to median: %" + GST_TIME_FORMAT " > 2 * %" GST_TIME_FORMAT, domain->domain, + GST_TIME_ARGS (mean_path_delay), GST_TIME_ARGS (median)); + ret = FALSE; + goto out; + } + } +#endif + #ifdef USE_RUNNING_AVERAGE_DELAY /* Track an average round trip time, for a bit of smoothing */ /* Always update before discarding a sample, so genuine changes in @@ -1344,6 +1405,7 @@ handle_sync_message (PtpMessage * msg, GstClockTime receive_time) if (!domain) { gchar *clock_name; + domain = g_new0 (PtpDomainData, 1); domain->domain = msg->domain_number; clock_name = g_strdup_printf ("ptp-clock-%u", domain->domain); @@ -1351,6 +1413,7 @@ handle_sync_message (PtpMessage * msg, GstClockTime receive_time) g_object_new (GST_TYPE_SYSTEM_CLOCK, "name", clock_name, NULL); g_free (clock_name); g_queue_init (&domain->pending_syncs); + domain->last_path_delays_missing = 9; domain_data = g_list_prepend (domain_data, domain); g_mutex_lock (&domain_clocks_lock); |