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--></style><title>Re: [Live-devel] Mpeg1or2 Stream very
jittery</title></head><body>
<div>First, rather than 'polling' (with a 50 ms delay) to check
whether new data can be read, it is better to use the new 'event
trigger' mechanism. See "liveMedia/DeviceSource.cpp"
for a model on how to do this.</div>
<div><br></div>
<div><br></div>
<blockquote type="cite" cite><font face="Wingdings"
size="-1">Ø</font><font face="Times New Roman"
size="-2"> </font><font
face="Arial" size="-1"> For MPEG2 we are using this class
MPEG1or2VideoStreamDiscreteFramer.</font></blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1">So when I
see this code I observe that a lot of manipulation is done to the
presentation time. So is it possible that the time stamp values are
getting jumbled here?</font></blockquote>
<div><br></div>
<div>"MPEG1or2VideoStreamDiscreteFramer" assumes that its
input frames are in 'decoding order' - i.e., the order in which frames
should be fed into a decoder (at the receiving end). This is the
same order in which frames should be sent across the network (via
RTP).</div>
<div><br></div>
<div>The 'preentation time' for each frame, however, will be different
- it corresponds to the time that each frame will be displayed on the
(receiver's) screen. Therefore, the
"MPEG1or2VideoStreamDiscreteFramer" code adjusts the
presentation times as appropriate (if the stream contains "B"
frames).</div>
<div><br></div>
<div>To summarize: If your input data frames are being delivered in
decoding order, then everything should be OK; any 'jittery' behavior
that you see must be due to something else (unrelated to our code).
However, if your input data frames are *not* being delivered (to
"MPEG1or2VideoStreamDiscreteFramer") in decoding order, then
you will need to fix this.</div>
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</pre></x-sigsep>
<div><br>
Ross Finlayson<br>
Live Networks, Inc.<br>
http://www.live555.com/</div>
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