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Calculate the timestamp for outbound RTP if we don't have timing information

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This patch calculates the timestamp for outbound RTP when we don't have timing
information. This uses the same approach in res_rtp_asterisk. Thanks to both
Pietro and Tzafrir for providing patches.

(closes issue ASTERISK-19883)
Reported by: Giacomo Trovato
Tested by: Pietro Bertera, Tzafrir Cohen
patches:
  rtp-timestamp-1.8.patch uploaded by tzafrir (License 5035)
  rtp-timestamp.patch uploaded by pbertera (License 5943)


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@385636 65c4cc65-6c06-0410-ace0-fbb531ad65f3
This commit is contained in:
Matthew Jordan
2013-04-14 02:58:57 +00:00
parent a73ffd9d25
commit 5a756f15f8
1 changed files with 40 additions and 2 deletions
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42
res/res_rtp_multicast.c
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@@ -90,6 +90,8 @@ struct multicast_rtp {
unsigned int ssrc; unsigned int ssrc;
/*! Sequence number, used when creating/sending the RTP packet */ /*! Sequence number, used when creating/sending the RTP packet */
uint16_t seqno; uint16_t seqno;
unsigned int lastts;
struct timeval txcore;
}; };
/* Forward Declarations */ /* Forward Declarations */
@@ -140,6 +142,30 @@ static int multicast_rtp_new(struct ast_rtp_instance *instance, struct sched_con
return 0; return 0;
} }
static int rtp_get_rate(format_t format)
{
return (format == AST_FORMAT_G722) ? 8000 : ast_format_rate(format);
}
static unsigned int calc_txstamp(struct multicast_rtp *rtp, struct timeval *delivery)
{
struct timeval t;
long ms;
if (ast_tvzero(rtp->txcore)) {
rtp->txcore = ast_tvnow();
rtp->txcore.tv_usec -= rtp->txcore.tv_usec % 20000;
}
t = (delivery && !ast_tvzero(*delivery)) ? *delivery : ast_tvnow();
if ((ms = ast_tvdiff_ms(t, rtp->txcore)) < 0) {
ms = 0;
}
rtp->txcore = t;
return (unsigned int) ms;
}
/*! \brief Helper function which populates a control packet with useful information and sends it */ /*! \brief Helper function which populates a control packet with useful information and sends it */
static int multicast_send_control_packet(struct ast_rtp_instance *instance, struct multicast_rtp *multicast, int command) static int multicast_send_control_packet(struct ast_rtp_instance *instance, struct multicast_rtp *multicast, int command)
{ {
@@ -209,12 +235,15 @@ static int multicast_rtp_write(struct ast_rtp_instance *instance, struct ast_fra
struct ast_frame *f = frame; struct ast_frame *f = frame;
struct ast_sockaddr remote_address; struct ast_sockaddr remote_address;
int hdrlen = 12, res = 0, codec; int hdrlen = 12, res = 0, codec;
int rate;
unsigned char *rtpheader; unsigned char *rtpheader;
unsigned int ms = calc_txstamp(multicast, &frame->delivery);
/* We only accept audio, nothing else */ /* We only accept audio, nothing else */
if (frame->frametype != AST_FRAME_VOICE) { if (frame->frametype != AST_FRAME_VOICE) {
return 0; return 0;
} }
rate = rtp_get_rate(frame->subclass.codec) / 1000;
/* Grab the actual payload number for when we create the RTP packet */ /* Grab the actual payload number for when we create the RTP packet */
if ((codec = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(instance), 1, frame->subclass.codec)) < 0) { if ((codec = ast_rtp_codecs_payload_code(ast_rtp_instance_get_codecs(instance), 1, frame->subclass.codec)) < 0) {
@@ -226,11 +255,20 @@ static int multicast_rtp_write(struct ast_rtp_instance *instance, struct ast_fra
f = ast_frdup(frame); f = ast_frdup(frame);
} }
/* Calucate last TS */
multicast->lastts = multicast->lastts + ms * rate;
/* Construct an RTP header for our packet */ /* Construct an RTP header for our packet */
rtpheader = (unsigned char *)(f->data.ptr - hdrlen); rtpheader = (unsigned char *)(f->data.ptr - hdrlen);
put_unaligned_uint32(rtpheader, htonl((2 << 30) | (codec << 16) | (multicast->seqno))); put_unaligned_uint32(rtpheader, htonl((2 << 30) | (codec << 16) | (multicast->seqno)));
put_unaligned_uint32(rtpheader + 4, htonl(f->ts * 8)); put_unaligned_uint32(rtpheader + 4, htonl(multicast->lastts));
put_unaligned_uint32(rtpheader + 8, htonl(multicast->ssrc));
if (ast_test_flag(f, AST_FRFLAG_HAS_TIMING_INFO)) {
put_unaligned_uint32(rtpheader + 4, htonl(f->ts * 8));
}
else {
put_unaligned_uint32(rtpheader + 8, htonl(multicast->ssrc));
}
/* Increment sequence number and wrap to 0 if it overflows 16 bits. */ /* Increment sequence number and wrap to 0 if it overflows 16 bits. */
multicast->seqno = 0xFFFF & (multicast->seqno + 1); multicast->seqno = 0xFFFF & (multicast->seqno + 1);