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mgcp/rtp: Refactor timestamp offset calculation into own function

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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
This commit is contained in:
Jacob Erlbeck
2013-12-10 13:09:37 +01:00
committed by Holger Hans Peter Freyther
parent e8ae1ac76a
commit 33f300915a
1 changed files with 66 additions and 32 deletions
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98
openbsc/src/libmgcp/mgcp_network.c
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@@ -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 */