DTXu: mark beginning of speech burst in RTP

Set Marker bit in RTP header to mark the beginning of talkspurt.

Change-Id: I55bcc950f176c097b3427aca5f86a909bde42ae3
Related: OS#1562

1 files changed, 44 insertions, 6 deletions

diff --git a/src/osmo-bts-sysmo/tch.c b/src/osmo-bts-sysmo/tch.c
index d8ba16f3..322e4574 100644
--- a/src/osmo-bts-sysmo/tch.c
+++ b/src/osmo-bts-sysmo/tch.c
@@ -151,7 +151,8 @@ uint8_t *get_payload_addr(struct msgb *msg)
 	return &msu_param->u8Buffer[1];
 }
 
-static struct msgb *l1_to_rtppayload_fr(uint8_t *l1_payload, uint8_t payload_len)
+static struct msgb *l1_to_rtppayload_fr(uint8_t *l1_payload, uint8_t payload_len,
+					struct gsm_lchan *lchan)
 {
 	struct msgb *msg;
 	uint8_t *cur;
@@ -176,6 +177,13 @@ static struct msgb *l1_to_rtppayload_fr(uint8_t *l1_payload, uint8_t payload_len
 	cur[0] |= 0xD0;
 #endif /* USE_L1_RTP_MODE */
 
+	if (osmo_fr_check_sid(l1_payload, payload_len))
+		lchan->tch.ul_sid = true;
+	else if (lchan->tch.ul_sid) {
+		lchan->tch.ul_sid = false;
+		lchan->rtp_tx_marker = true;
+	}
+
 	return msg;
 }
 
@@ -207,7 +215,9 @@ static int rtppayload_to_l1_fr(uint8_t *l1_payload, uint8_t *rtp_payload,
 }
 
 #if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
-static struct msgb *l1_to_rtppayload_efr(uint8_t *l1_payload, uint8_t payload_len)
+static struct msgb *l1_to_rtppayload_efr(uint8_t *l1_payload,
+					 uint8_t payload_len,
+					 struct gsm_lchan *lchan)
 {
 	struct msgb *msg;
 	uint8_t *cur;
@@ -231,6 +241,17 @@ static struct msgb *l1_to_rtppayload_efr(uint8_t *l1_payload, uint8_t payload_le
 
 	cur[0] |= 0xC0;
 #endif /* USE_L1_RTP_MODE */
+	enum osmo_amr_type ft;
+	enum osmo_amr_quality bfi;
+	uint8_t cmr;
+	int8_t sti, cmi;
+	osmo_amr_rtp_dec(l1_payload, payload_len, &cmr, &cmi, &ft, &bfi, &sti);
+	if (ft == AMR_GSM_EFR_SID)
+		lchan->tch.ul_sid = true;
+	else if (lchan->tch.ul_sid) {
+		lchan->tch.ul_sid = false;
+		lchan->rtp_tx_marker = true;
+	}
 	return msg;
 }
 
@@ -256,7 +277,8 @@ static int rtppayload_to_l1_efr(uint8_t *l1_payload, const uint8_t *rtp_payload,
 #warning No EFR support in L1
 #endif /* L1_HAS_EFR */
 
-static struct msgb *l1_to_rtppayload_hr(uint8_t *l1_payload, uint8_t payload_len)
+static struct msgb *l1_to_rtppayload_hr(uint8_t *l1_payload, uint8_t payload_len,
+					struct gsm_lchan *lchan)
 {
 	struct msgb *msg;
 	uint8_t *cur;
@@ -279,6 +301,13 @@ static struct msgb *l1_to_rtppayload_hr(uint8_t *l1_payload, uint8_t payload_len
 	osmo_revbytebits_buf(cur, GSM_HR_BYTES);
 #endif /* USE_L1_RTP_MODE */
 
+	if (osmo_hr_check_sid(l1_payload, payload_len))
+		lchan->tch.ul_sid = true;
+	else if (lchan->tch.ul_sid) {
+		lchan->tch.ul_sid = false;
+		lchan->rtp_tx_marker = true;
+	}
+
 	return msg;
 }
 
@@ -596,6 +625,15 @@ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
 		    lchan->type != GSM_LCHAN_TCH_F)
 			goto err_payload_match;
 		break;
+	case GsmL1_TchPlType_Amr_Onset:
+		if (lchan->type != GSM_LCHAN_TCH_H &&
+		    lchan->type != GSM_LCHAN_TCH_F)
+			goto err_payload_match;
+		/* according to 3GPP TS 26.093 ONSET frames precede the first
+		   speech frame of a speech burst - set the marker for next RTP
+		   frame and drop last SID */
+		lchan->rtp_tx_marker = true;
+		break;
 	default:
 		LOGP(DL1C, LOGL_NOTICE, "%s Rx Payload Type %s is unsupported\n",
 			gsm_lchan_name(lchan),
@@ -606,14 +644,14 @@ int l1if_tch_rx(struct gsm_bts_trx *trx, uint8_t chan_nr, struct msgb *l1p_msg)
 
 	switch (payload_type) {
 	case GsmL1_TchPlType_Fr:
-		rmsg = l1_to_rtppayload_fr(payload, payload_len);
+		rmsg = l1_to_rtppayload_fr(payload, payload_len, lchan);
 		break;
 	case GsmL1_TchPlType_Hr:
-		rmsg = l1_to_rtppayload_hr(payload, payload_len);
+		rmsg = l1_to_rtppayload_hr(payload, payload_len, lchan);
 		break;
 #if defined(L1_HAS_EFR) && defined(USE_L1_RTP_MODE)
 	case GsmL1_TchPlType_Efr:
-		rmsg = l1_to_rtppayload_efr(payload, payload_len);
+		rmsg = l1_to_rtppayload_efr(payload, payload_len, lchan);
 		break;
 #endif
 	case GsmL1_TchPlType_Amr: