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rtpenc: Start the sequence numbers from a random offset

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Expose the current sequence number via an AVOption - this can
be used both for setting the initial sequence number, or for
querying the current number.

Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2012-12-07 11:12:28 +02:00
parent 9146e872c6
commit ab587f39b2
3 changed files with 11 additions and 3 deletions
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10
libavformat/rtpenc.c
View File

@ -35,6 +35,7 @@ static const AVOption options[] = {
{ "payload_type", "Specify RTP payload type", offsetof(RTPMuxContext, payload_type), AV_OPT_TYPE_INT, {.i64 = -1 }, -1, 127, AV_OPT_FLAG_ENCODING_PARAM },
{ "ssrc", "Stream identifier", offsetof(RTPMuxContext, ssrc), AV_OPT_TYPE_INT, { .i64 = 0 }, INT_MIN, INT_MAX, AV_OPT_FLAG_ENCODING_PARAM },
{ "cname", "CNAME to include in RTCP SR packets", offsetof(RTPMuxContext, cname), AV_OPT_TYPE_STRING, { .str = NULL }, 0, 0, AV_OPT_FLAG_ENCODING_PARAM },
{ "seq", "Starting sequence number", offsetof(RTPMuxContext, seq), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, 65535, AV_OPT_FLAG_ENCODING_PARAM },
{ NULL },
};
@ -124,6 +125,13 @@ static int rtp_write_header(AVFormatContext *s1)
/* Round the NTP time to whole milliseconds. */
s->first_rtcp_ntp_time = (s1->start_time_realtime / 1000) * 1000 +
NTP_OFFSET_US;
// Pick a random sequence start number, but in the lower end of the
// available range, so that any wraparound doesn't happen immediately.
// (Immediate wraparound would be an issue for SRTP.)
if (s->seq < 0)
s->seq = av_get_random_seed() & 0x0fff;
else
s->seq &= 0xffff; // Use the given parameter, wrapped to the right interval
if (s1->packet_size) {
if (s1->pb->max_packet_size)
@ -309,7 +317,7 @@ void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m)
avio_write(s1->pb, buf1, len);
avio_flush(s1->pb);
s->seq++;
s->seq = (s->seq + 1) & 0xffff;
s->octet_count += len;
s->packet_count++;
}

2
libavformat/rtpenc.h
View File

@ -31,7 +31,7 @@ struct RTPMuxContext {
int payload_type;
uint32_t ssrc;
const char *cname;
uint16_t seq;
int seq;
uint32_t timestamp;
uint32_t base_timestamp;
uint32_t cur_timestamp;

2
libavformat/version.h
View File

@ -31,7 +31,7 @@
#define LIBAVFORMAT_VERSION_MAJOR 54
#define LIBAVFORMAT_VERSION_MINOR 21
#define LIBAVFORMAT_VERSION_MICRO 1
#define LIBAVFORMAT_VERSION_MICRO 2
#define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
LIBAVFORMAT_VERSION_MINOR, \