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authorJacob Erlbeck <jerlbeck@sysmocom.de>2013-12-10 13:09:37 +0100
committerHolger Hans Peter Freyther <holger@moiji-mobile.com>2013-12-13 13:45:19 +0100
commit33f300915a09ddd16dfcdac2912d79bcdb361bf7 (patch)
tree781f56b1d19db4d85d9be742009d3c07dd2a07bb /openbsc/src/libmgcp/mgcp_network.c
parente8ae1ac76ade2ee490e482871817d406f17ab0b4 (diff)
mgcp/rtp: Refactor timestamp offset calculation into own function
Currently the timestamp offset calculation is done in two different places. This patch moves and unifies both code parts into a separate function. Sponsored-by: On-Waves ehf
Diffstat (limited to 'openbsc/src/libmgcp/mgcp_network.c')
-rw-r--r--openbsc/src/libmgcp/mgcp_network.c98
1 files changed, 66 insertions, 32 deletions
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index bf205d1c..8bd8afba 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -200,6 +200,58 @@ static int check_rtp_timestamp(struct mgcp_endpoint *endp,
return 1;
}
+/* Set the timestamp offset according to the packet duration. */
+static int adjust_rtp_timestamp_offset(struct mgcp_endpoint *endp,
+ struct mgcp_rtp_state *state,
+ struct mgcp_rtp_end *rtp_end,
+ struct sockaddr_in *addr,
+ int16_t delta_seq, uint32_t timestamp)
+{
+ int32_t tsdelta = state->packet_duration;
+ int timestamp_offset;
+
+ if (tsdelta == 0) {
+ tsdelta = state->out_stream.last_tsdelta;
+ if (tsdelta != 0) {
+ LOGP(DMGCP, LOGL_NOTICE,
+ "A fixed packet duration is not available on 0x%x, "
+ "using last output timestamp delta instead: %d "
+ "from %s:%d in %d\n",
+ ENDPOINT_NUMBER(endp), tsdelta,
+ inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+ endp->conn_mode);
+ } else {
+ tsdelta = rtp_end->rate * 20 / 1000;
+ LOGP(DMGCP, LOGL_NOTICE,
+ "Fixed packet duration and last timestamp delta "
+ "are not available on 0x%x, "
+ "using fixed 20ms instead: %d "
+ "from %s:%d in %d\n",
+ ENDPOINT_NUMBER(endp), tsdelta,
+ inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+ endp->conn_mode);
+ }
+ }
+
+ timestamp_offset =
+ state->out_stream.last_timestamp - timestamp +
+ delta_seq * tsdelta;
+
+ if (state->timestamp_offset != timestamp_offset) {
+ state->timestamp_offset = timestamp_offset;
+
+ LOGP(DMGCP, LOGL_NOTICE,
+ "Timestamp offset change on 0x%x SSRC: %u "
+ "SeqNo delta: %d, TS offset: %d, "
+ "from %s:%d in %d\n",
+ ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
+ delta_seq, state->timestamp_offset,
+ inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
+ endp->conn_mode);
+ }
+
+ return timestamp_offset;
+}
/**
* The RFC 3550 Appendix A assumes there are multiple sources but
@@ -259,22 +311,14 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
state->in_stream.ssrc = ssrc;
if (rtp_end->force_constant_ssrc) {
- int32_t tsdelta = state->out_stream.last_tsdelta;
- if (tsdelta == 0) {
- tsdelta = state->packet_duration;
- LOGP(DMGCP, LOGL_NOTICE,
- "Timestamp delta is not available on 0x%x, "
- "using packet duration instead: %d "
- "from %s:%d in %d\n",
- ENDPOINT_NUMBER(endp), tsdelta,
- inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
- endp->conn_mode);
- }
+ const int16_t delta_seq = 1;
+
state->seq_offset =
- (state->out_stream.last_seq + 1) - seq;
- state->timestamp_offset =
- (state->out_stream.last_timestamp + tsdelta) -
- timestamp;
+ (state->out_stream.last_seq + delta_seq) - seq;
+
+ adjust_rtp_timestamp_offset(endp, state, rtp_end, addr,
+ delta_seq, timestamp);
+
state->patch_ssrc = 1;
ssrc = state->orig_ssrc;
if (rtp_end->force_constant_ssrc != -1)
@@ -282,10 +326,10 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
LOGP(DMGCP, LOGL_NOTICE,
"SSRC patching enabled on 0x%x SSRC: %u "
- "offset: %d tsdelta: %d "
+ "SeqNo offset: %d, TS offset: %d "
"from %s:%d in %d\n",
ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
- state->seq_offset, tsdelta,
+ state->seq_offset, state->timestamp_offset,
inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
endp->conn_mode);
}
@@ -307,22 +351,12 @@ void mgcp_patch_and_count(struct mgcp_endpoint *endp, struct mgcp_rtp_state *sta
if (rtp_end->force_constant_timing &&
state->out_stream.ssrc == ssrc && state->packet_duration) {
- int delta_seq = seq + state->seq_offset - state->out_stream.last_seq;
- int timestamp_offset =
- state->out_stream.last_timestamp - timestamp +
- delta_seq * state->packet_duration;
- if (state->timestamp_offset != timestamp_offset) {
- state->timestamp_offset = timestamp_offset;
+ /* Update the timestamp offset */
+ const int delta_seq =
+ seq + state->seq_offset - state->out_stream.last_seq;
- LOGP(DMGCP, LOGL_NOTICE,
- "Timestamp patching enabled on 0x%x SSRC: %u "
- "SeqNo delta: %d, TS offset: %d, "
- "from %s:%d in %d\n",
- ENDPOINT_NUMBER(endp), state->in_stream.ssrc,
- delta_seq, state->timestamp_offset,
- inet_ntoa(addr->sin_addr), ntohs(addr->sin_port),
- endp->conn_mode);
- }
+ adjust_rtp_timestamp_offset(endp, state, rtp_end, addr,
+ delta_seq, timestamp);
}
/* Store the updated SSRC back to the packet */