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--></style><title>Re: [Live-devel] Control Flow
Basics</title></head><body>
<blockquote type="cite" cite><font face="Arial" size="-1"
color="#000080">Sorry to be dense. I saw the text you provided from
the FAQs, but wasn't quite sure what it meant. As it is written, I
understand this to mean that a sink module that is part of a chain of
nodes from the source to the destination sink will receive data from
an upstream source (or a sink that is forwarding packets from an
upstream node). If the sink module is the final destination, it will
consume the packets. If it is an intermediate node, then it will
transmit RTP packets to the next downlink sink.</font></blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1"
color="#000080"> </font></blockquote>
<blockquote type="cite" cite><font face="Arial" size="-1"
color="#000080">Is that a correct interpretation?</font></blockquote>
<div><br></div>
<div>No. First, in our terminology, a 'sink' is only at the end
of a data chain - i.e.</div>
<div><x-tab> </x-tab>source
-> filter (source) -> filter (source) -> sink</div>
<div>Second, as explained in the FAQ, this flow of data (from one or
more sources, to a sink) is what occurs ***within an application***.
It has nothing to do with the flow of network packets ***between
applications***.</div>
<div><br></div>
<div>That's why RTP packets are transmitted by a 'sink' object (a
"RTPSink") - because such an object appears at the end of a
flow of data (that usually originated with data from a file source or
an encoder source). Similarly, RTP packets are received, over
the network, by a 'source' object (a "RTPSource") -
because such an object acts as a source of data (audio or video
frames) that is then consumed by other, downstream objects (such as a
decoder, or a file 'sink').</div>
<div><br></div>
<div><br></div>
<blockquote type="cite" cite><font face="Arial" size="-1"
color="#000080">Also, suppose I only have one source and one
sink.</font></blockquote>
<div><br></div>
<div>If you have a pair of applications - one transmitting data over
the network, and the other receiving data from the network - then you
won't just have "one source and one sink". Instead,
each application (transmitting and receiving) will have one sink, and
one or more sources. Once again, the 'source', 'filter', 'sink'
terminology applies only to the data flow ***within an
application***.</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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