mgcp: Add packet size (ptime) conversion
The current transcoder implemenation always does a 1:1 recoding
concerning the duration of a packet. So RTP timestamps and sequence
numbers are not modified.
This is not sufficient in some cases, e.g. when the BTS does only
allow for a single fixed ptime.
This patch decouples encoding from decoding and moves the decoded
samples to the state structure so that samples can be combined or
drain according to the packaging of incoming and outgoing packets.
This patch incorporates parts of Holger's experimental fixes in
0e669e05^..9eba68f9.
Ticket: OW#1111
Sponsored-by: On-Waves ehf
diff --git a/openbsc/src/libmgcp/mgcp_network.c b/openbsc/src/libmgcp/mgcp_network.c
index 05c3e77..219d3f9 100644
--- a/openbsc/src/libmgcp/mgcp_network.c
+++ b/openbsc/src/libmgcp/mgcp_network.c
@@ -340,7 +340,7 @@
return timestamp_error;
}
-int mgcp_rtp_processing_default(struct mgcp_rtp_end *dst_end,
+int mgcp_rtp_processing_default(struct mgcp_endpoint *endp, struct mgcp_rtp_end *dst_end,
char *data, int *len, int buf_size)
{
return 0;
@@ -614,12 +614,28 @@
if (!rtp_end->output_enabled)
rtp_end->dropped_packets += 1;
else if (is_rtp) {
- mgcp_patch_and_count(endp, rtp_state, rtp_end, addr, buf, rc);
- endp->cfg->rtp_processing_cb(rtp_end, buf, &rc, RTP_BUF_SIZE);
- forward_data(rtp_end->rtp.fd, &endp->taps[tap_idx], buf, rc);
- return mgcp_udp_send(rtp_end->rtp.fd,
- &rtp_end->addr,
- rtp_end->rtp_port, buf, rc);
+ int cont;
+ int nbytes = 0;
+ int len = rc;
+ mgcp_patch_and_count(endp, rtp_state, rtp_end, addr, buf, len);
+ do {
+ cont = endp->cfg->rtp_processing_cb(endp, rtp_end,
+ buf, &len, RTP_BUF_SIZE);
+ if (cont < 0)
+ break;
+
+ forward_data(rtp_end->rtp.fd, &endp->taps[tap_idx],
+ buf, len);
+ rc = mgcp_udp_send(rtp_end->rtp.fd,
+ &rtp_end->addr,
+ rtp_end->rtp_port, buf, len);
+
+ if (rc <= 0)
+ return rc;
+ nbytes += rc;
+ len = cont;
+ } while (len > 0);
+ return nbytes;
} else if (!tcfg->omit_rtcp) {
return mgcp_udp_send(rtp_end->rtcp.fd,
&rtp_end->addr,
diff --git a/openbsc/src/libmgcp/mgcp_protocol.c b/openbsc/src/libmgcp/mgcp_protocol.c
index 6e974f1..21b9ff0 100644
--- a/openbsc/src/libmgcp/mgcp_protocol.c
+++ b/openbsc/src/libmgcp/mgcp_protocol.c
@@ -621,6 +621,15 @@
rtp->channels = channels;
rtp->subtype_name = talloc_strdup(ctx, audio_codec);
rtp->audio_name = talloc_strdup(ctx, audio_name);
+
+ if (!strcmp(audio_codec, "G729")) {
+ rtp->frame_duration_num = 10;
+ rtp->frame_duration_den = 1000;
+ } else {
+ rtp->frame_duration_num = DEFAULT_RTP_AUDIO_FRAME_DUR_NUM;
+ rtp->frame_duration_den = DEFAULT_RTP_AUDIO_FRAME_DUR_DEN;
+ }
+
if (channels != 1)
LOGP(DMGCP, LOGL_NOTICE,
"Channels != 1 in SDP: '%s'\n", audio_name);
@@ -944,11 +953,16 @@
set_audio_info(p->cfg, &endp->bts_end, tcfg->audio_payload, tcfg->audio_name);
endp->bts_end.fmtp_extra = talloc_strdup(tcfg->endpoints,
tcfg->audio_fmtp_extra);
- if (have_sdp) {
+ if (have_sdp)
parse_sdp_data(&endp->net_end, p);
- setup_rtp_processing(endp);
+
+ if (p->cfg->bts_force_ptime) {
+ endp->bts_end.packet_duration_ms = p->cfg->bts_force_ptime;
+ endp->bts_end.force_output_ptime = 1;
}
+ setup_rtp_processing(endp);
+
/* policy CB */
if (p->cfg->policy_cb) {
int rc;
diff --git a/openbsc/src/libmgcp/mgcp_vty.c b/openbsc/src/libmgcp/mgcp_vty.c
index 1f8a63a..26b5706 100644
--- a/openbsc/src/libmgcp/mgcp_vty.c
+++ b/openbsc/src/libmgcp/mgcp_vty.c
@@ -366,6 +366,26 @@
RTP_STR
"Apply IP_TOS to the audio stream\n" "The DSCP value\n")
+#define FORCE_PTIME_STR "Force a fixed ptime for packets sent to the BTS"
+DEFUN(cfg_mgcp_rtp_force_ptime,
+ cfg_mgcp_rtp_force_ptime_cmd,
+ "rtp force-ptime (10|20|40)",
+ RTP_STR FORCE_PTIME_STR
+ "The required ptime (packet duration) in ms\n")
+{
+ g_cfg->bts_force_ptime = atoi(argv[0]);
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_mgcp_no_rtp_force_ptime,
+ cfg_mgcp_no_rtp_force_ptime_cmd,
+ "no rtp force-ptime",
+ NO_STR RTP_STR FORCE_PTIME_STR)
+{
+ g_cfg->bts_force_ptime = 0;
+ return CMD_SUCCESS;
+}
+
DEFUN(cfg_mgcp_sdp_fmtp_extra,
cfg_mgcp_sdp_fmtp_extra_cmd,
"sdp audio fmtp-extra .NAME",
@@ -1123,6 +1143,8 @@
install_element(MGCP_NODE, &cfg_mgcp_rtp_transcoder_base_cmd);
install_element(MGCP_NODE, &cfg_mgcp_rtp_ip_dscp_cmd);
install_element(MGCP_NODE, &cfg_mgcp_rtp_ip_tos_cmd);
+ install_element(MGCP_NODE, &cfg_mgcp_rtp_force_ptime_cmd);
+ install_element(MGCP_NODE, &cfg_mgcp_no_rtp_force_ptime_cmd);
install_element(MGCP_NODE, &cfg_mgcp_rtp_keepalive_cmd);
install_element(MGCP_NODE, &cfg_mgcp_rtp_keepalive_once_cmd);
install_element(MGCP_NODE, &cfg_mgcp_no_rtp_keepalive_cmd);