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test: avtp: crf: Check for rounding errors

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on average period calculation.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1073>
This commit is contained in:
Timo Wischer 2021-03-03 10:08:57 +01:00 committed by GStreamer Marge Bot
parent 5a25eb61b7
commit 214691b972
1 changed files with 59 additions and 4 deletions
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63
subprojects/gst-plugins-bad/tests/check/elements/avtpcrfbase.c
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@ -29,6 +29,10 @@
static struct avtp_crf_pdu *
generate_crf_pdu (int data_len, guint64 first_tstamp)
{
const guint64 base_freq = 48000;
const guint64 interval = 160;
const gdouble interval_time = 1.0e9 / base_freq * interval;
struct avtp_crf_pdu *crf_pdu =
g_malloc0 (sizeof (struct avtp_crf_pdu) + data_len);
@ -36,12 +40,14 @@ generate_crf_pdu (int data_len, guint64 first_tstamp)
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_SV, 1);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_STREAM_ID, 0xABCD1234ABCD1234);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_TYPE, AVTP_CRF_TYPE_AUDIO_SAMPLE);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_BASE_FREQ, 48000);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_BASE_FREQ, base_freq);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_PULL, 1);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_CRF_DATA_LEN, data_len);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_TIMESTAMP_INTERVAL, 160);
for (int i = 0; i < data_len / 8; i++)
crf_pdu->crf_data[i] = htobe64 (first_tstamp + i * 3333333);
avtp_crf_pdu_set (crf_pdu, AVTP_CRF_FIELD_TIMESTAMP_INTERVAL, interval);
for (int i = 0; i < data_len / 8; i++) {
const guint64 offset = i * interval_time;
crf_pdu->crf_data[i] = htobe64 (first_tstamp + offset);
}
return crf_pdu;
}
@ -522,6 +528,54 @@ GST_START_TEST (test_calculate_average_period_multiple_crf_tstamps)
GST_END_TEST;
/*
* Test for rounding error
*/
GST_START_TEST (test_calculate_average_period_rounding_error)
{
/* the presentation time in ns */
const GstClockTimeDiff ptime = 50000000;
/* the time in ns of one sync event e.g. one audio sample @48kHz */
const gdouble event_interval = 1.0e9 / 48000;
/* the presentation time measured in sync events (e.g. sample rate)
* for class B traffic with a presentation time of 50ms.
*/
const GstClockTime ptime_in_events = ptime / event_interval;
/* With 4 timestamps generate_crf_pdu() multiples the interval time
* with 3. This results into an integer time stamp in nsi without decimal
* digits. Therefore the rounding issue when generating the timestamps for
* the CRF PDU is avoided here.
*/
int data_len = 32;
struct avtp_crf_pdu *crf_pdu = generate_crf_pdu (data_len, 1000);
gdouble past_periods[10] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
GstAvtpCrfBase *avtpcrfbase = g_object_new (GST_TYPE_AVTP_CRF_BASE, NULL);
GstAvtpCrfThreadData *thread_data = &avtpcrfbase->thread_data;
setup_thread_defaults (avtpcrfbase, past_periods);
thread_data->timestamp_interval = 160;
thread_data->num_pkt_tstamps = data_len / sizeof (uint64_t);
thread_data->past_periods_iter = 0;
thread_data->periods_stored = 0;
calculate_average_period (avtpcrfbase, crf_pdu);
/* When internally using integer for average_period calculation the following
* multiplication will result to (20833 * 2400=) 49999200ns. This value
* differs by 800ns from the original presentation time of 50ms. When using
* double this rounding error is avoided.
*/
fail_unless_equals_float ((thread_data->average_period * ptime_in_events),
ptime);
gst_object_unref (avtpcrfbase);
g_free (crf_pdu);
}
GST_END_TEST;
/*
* Test for an overflow in the 64-bit CRF timestamp in the CRF AVTPDU when
* there are multiple CRF timestamps in a packet.
@ -776,6 +830,7 @@ avtpcrfbase_suite (void)
tcase_add_test (tc_chain, test_validate_crf_pdu_tstamps_not_monotonic);
tcase_add_test (tc_chain, test_gst_base_freq_multiplier);
tcase_add_test (tc_chain, test_calculate_average_period_multiple_crf_tstamps);
tcase_add_test (tc_chain, test_calculate_average_period_rounding_error);
tcase_add_test (tc_chain,
test_calculate_average_period_multiple_crf_tstamps_64_bit_overflow);
tcase_add_test (tc_chain, test_calculate_average_period_single_crf_tstamp);