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--></style><title>Re: [Live-devel] Timestamp gap in RTCP Report for
MPEG1or</title></head><body>
<blockquote type="cite" cite><font face="Arial"
size="-1">fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP
timestamp: 21097<br>
sending REPORT<br>
fTimestampBase: 0xae0daf0d, tv: 683383.099932, RTP timestamp:
101919</font></blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1">Creating
RTCP SR packet, SSRC is 0x6da5, NTP is : tv: 683383.099932, TimeStamp
is: 101919<br>
sending RTCP packet<br>
80c80006 00006da5 83b4ebf7 199524c0 00018e1f 000000db 0003c76d
81ca0005 00006da5 010a7377 6f70742d 766f6970 00000000<br>
schedule(1.015347->683384.121916)</font></blockquote>
<blockquote type="cite" cite><font face="Arial"
size="-1">fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP
timestamp: 21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097<br>
fTimestampBase: 0xae0daf0d, tv: 683382.201906, RTP timestamp:
21097</font></blockquote>
<blockquote type="cite" cite><font face="Arial"
size="-1">fTimestampBase: 0xae0daf0d, tv: 683382.235273, RTP
timestamp: 24100<br>
fTimestampBase: 0xae0daf0d, tv: 683382.235273, RTP timestamp:
24100</font><br>
</blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1">Obviously
the TimeStamp value of the RTCP SR packet should be between 21097 and
24100.</font></blockquote>
<div><br></div>
<div>No - because the 'NTP' time (683383.099932) that's used for the
RTCP SR packet is not between 683382.201906 and 683382.235273.
The RTP timestamp of 101919 corresponds to the time
683383.099932.</div>
<div><br></div>
<div>It's perfectly OK for the NTP time that's used in a RTCP
"SR" report to differ from the presentation time used in RTP
packets that bracket it. However, because the RTCP SR 'NTP' time
is computed using "gettimeofday()" (i.e., 'wall clock'
time), the presentation times for your media samples (that get passed
to RTP) *must* also be aligned with 'wall clock' time.</div>
<div><br></div>
<div>The timestamp generation code (for both RTP and RTCP) is
correct. However, for it to work correctly, you must feed it
correct presentation times.</div>
<x-sigsep><pre>--
</pre></x-sigsep>
<div><br>
Ross Finlayson<br>
Live Networks, Inc.<br>
http://www.live555.com/</div>
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