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fixed NTP generation for mpeg

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Originally committed as revision 2046 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Fabrice Bellard 2003-07-15 19:41:40 +00:00
parent b689213642
commit e5526b2c39
1 changed files with 24 additions and 7 deletions
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25
libavformat/rtp.c
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@ -98,6 +98,7 @@ typedef struct RTPContext {
int max_payload_size;
/* rtcp sender statistics receive */
int64_t last_rtcp_ntp_time;
int64_t first_rtcp_ntp_time;
uint32_t last_rtcp_timestamp;
/* rtcp sender statistics */
unsigned int packet_count;
@ -189,7 +190,7 @@ static inline uint32_t decode_be32(const uint8_t *p)
return (p[0] << 24) | (p[1] << 16) | (p[2] << 8) | p[3];
}
static inline uint32_t decode_be64(const uint8_t *p)
static inline uint64_t decode_be64(const uint8_t *p)
{
return ((uint64_t)decode_be32(p) << 32) | decode_be32(p + 4);
}
@ -201,6 +202,8 @@ static int rtcp_parse_packet(AVFormatContext *s1, const unsigned char *buf, int
if (buf[1] != 200)
return -1;
s->last_rtcp_ntp_time = decode_be64(buf + 8);
if (s->first_rtcp_ntp_time == AV_NOPTS_VALUE)
s->first_rtcp_ntp_time = s->last_rtcp_ntp_time;
s->last_rtcp_timestamp = decode_be32(buf + 16);
return 0;
}
@ -298,11 +301,23 @@ int rtp_parse_packet(AVFormatContext *s1, AVPacket *pkt,
break;
}
switch(st->codec.codec_id) {
case CODEC_ID_MP2:
case CODEC_ID_MPEG1VIDEO:
if (s->last_rtcp_ntp_time != AV_NOPTS_VALUE) {
int64_t addend;
/* XXX: is it really necessary to unify the timestamp base ? */
/* compute pts from timestamp with received ntp_time */
delta_timestamp = timestamp - s->last_rtcp_timestamp;
/* XXX: do conversion, but not needed for mpeg at 90 KhZ */
pkt->pts = s->last_rtcp_ntp_time + delta_timestamp;
/* convert to 90 kHz without overflow */
addend = (s->last_rtcp_ntp_time - s->first_rtcp_ntp_time) >> 14;
addend = (addend * 5625) >> 14;
pkt->pts = addend + delta_timestamp;
}
break;
default:
/* no timestamp info yet */
break;
}
return 0;
}
@ -313,6 +328,7 @@ static int rtp_read_header(AVFormatContext *s1,
RTPContext *s = s1->priv_data;
s->payload_type = -1;
s->last_rtcp_ntp_time = AV_NOPTS_VALUE;
s->first_rtcp_ntp_time = AV_NOPTS_VALUE;
return 0;
}
@ -613,7 +629,8 @@ static int rtp_write_packet(AVFormatContext *s1, int stream_index,
RTCP_TX_RATIO_DEN;
if (s->first_packet || rtcp_bytes >= 28) {
/* compute NTP time */
ntp_time = force_pts; // ((int64_t)force_pts << 28) / 5625
/* XXX: 90 kHz timestamp hardcoded */
ntp_time = ((int64_t)force_pts << 28) / 5625;
rtcp_send_sr(s1, ntp_time);
s->last_octet_count = s->octet_count;
s->first_packet = 0;