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add documentation for the new RTP modules

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git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@731 fefdeb5f-60dc-0310-8127-8f9354f1896f
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Lennart Poettering 2006-04-16 13:34:09 +00:00
parent 2f3fa42ca6
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97
doc/FAQ.html.in
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@ -67,7 +67,7 @@
<tt>realtime</tt>, or increase the fragment sizes of the audio
drivers. The former will allow Polypaudio to activate
<tt>SCHED_FIFO</tt> high priority scheduling (root rights are dropped
immediately after this) Keep in mind that this is a potential security hole!</p></li>
immediately after this). Keep in mind that this is a potential security hole!</p></li>
<li><p><b>The <tt>polypaudio</tt> executable is installed SUID root by default. Why this? Isn't this a potential security hole?</b></p>
@ -103,7 +103,12 @@ in <tt>~/.polypaudio/</tt>.</p></li>
<li><p><b>How do I use polypaudio over the network?</b></p>
<p>Just set <tt>$POLYP_SERVER</tt> to the host name of the polypaudio server.</p>
<p>Just set <tt>$POLYP_SERVER</tt> to the host name of the polypaudio
server. For authentication you need the same auth cookies on all sides. For
that copy <tt>~./polypaudio-cookie</tt> to all clients that shall
be allowed to connect.</p>
<p>Alternatively the authorization cookies can be stored in the X11 server.</p></li>
<li><p><b>Is polypaudio capable of providing synchronized audio playback over the network for movie players like <tt>mplayer</tt>?</b></p>
@ -126,7 +131,7 @@ connect to a running polypaudio daemon try using the following commands:</p>
<pre>killall -USR2 polypaudio
bidilink unix-client:/tmp/polypaudio/cli</pre>
<p><i>BTW: Someone should package that great tool for Debian!</i></p>
<p><i>BTW: Someone should package this great tool for Debian!</i></p>
<p><b>New:</b> There's now a tool <tt>pacmd</tt> that automates sending SIGUSR2 to the daemon and running a bidilink like tool for you.</p>
</li>
@ -146,7 +151,91 @@ bidilink unix-client:/tmp/polypaudio/cli</pre>
</li>
<li><p><b>Why the heck does libpolyp link against libX11?</b></p>
<p>The Polypaudio client libraries look for some X11 root window properties for the credentials of the Polypaudio server to access. You may compile Polypaudio without X11 for disabling this.</p></li>
<p>The Polypaudio client libraries look for some X11 root window
properties for the credentials of the Polypaudio server to access. You
may compile Polypaudio without X11 for disabling this feature.</p></li>
<li><p><b>How can I use Polypaudio as an RTP based N:N multicast
conferencing solution for the LAN?</b></p> <p>After loading all the
necessary audio drivers for recording and playback, just load the RTP
reciever and sender modules with default parameters:</p>
<pre>
load-module module-rtp-send
load-module module-rtp-recv
</pre>
<p>As long as the Polypaudio daemon runs, the microphone data will be
streamed to the network and the data from other hosts is played back
locally. Please note that this may cause quite a lot of traffic. Hence
consider passing <tt>rate=8000 format=ulaw channels=1</tt> to the
sender module to save bandwith while still maintaining good quality
for speech transmission.</p></li>
<li><p><b>What is this RTP/SDP/SAP thing all about?</b></p>
<p>RTP is the <i>Realtime Transfer Protocol</i>. It is a well-known
protocol for transferring audio and video data over IP. SDP is the <i>Session
Description Protocol</i> and can be used to describe RTP sessions. SAP
is the <i>Session Announcement Protocol</i> and can be used to
announce RTP sessions that are described with SDP. (Modern SIP based VoIP phones use RTP/SDP for their sessions, too)</p>
<p>All three protocols are defined in IETF RFCs (RFC3550, RFC3551,
RFC2327, RFC2327). They can be used in both multicast and unicast
fashions. Polypaudio exclusively uses multicast RTP/SDP/SAP containing audio data.</p>
<p>For more information about using these technologies with Polypaudio have a look on the <a href="modules.html#rtp">respective module's documentation</a>.
<li><p><b>How can I use Polypaudio to stream music from my main PC to my LAN with multiple PCs with speakers?</b></p>
<p>On the sender side create an RTP sink:</p>
<pre>
load-module module-null-sink sink_name=rtp
load-module module-rtp-send source=rtp_monitor
set-default-sink rtp
</pre>
<p>This will make <tt>rtp</tt> the default sink, i.e. all applications will write to this virtual RTP device by default.</p>
<p>On the client sides just load the reciever module:</p>
<pre>
load-module module-rtp-recv
</pre>
<p>Now you can play your favourite music on the sender side and all clients will output it simultaneously.</p>
<p>BTW: You can have more than one sender machine set up like this. The audio data will be mixed on the client side.</p></li>
<li><p><b>How can I use Polypaudio to share a single LINE-IN/MIC jack on the entire LAN?</b></p>
<p>On the sender side simply load the RTP sender module:</p>
<pre>
load-module module-rtp-send
</pre>
<p>On the reciever sides, create an RTP source:</p>
<pre>
load-module module-null-sink sink_name=rtp
load-module module-rtp-recv sink=rtp
set-default-source rtp_monitor
</pre>
<p>Now the audio data will be available from the default source <tt>rtp_monitor</tt>.</p>
<li><p><b>When sending multicast RTP traffic it is recieved on the entire LAN but not by the sender machine itself!</b></p>
<p>Pass <tt>loop=1</tt> to the sender module!</p></li>
<li><p><b>Can I have more than one multicast RTP group?</b></p>
<p>Yes! Simply use a new multicast group address. Use
the <tt>destination</tt>/<tt>sap_address</tt> arguments of the RTP
modules to select them. Choose your group addresses from the range
<tt>225.0.0.x</tt> to make sure the audio data never leaves the LAN.</p></li>
</ol>

3
doc/README.html.in
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@ -44,7 +44,7 @@ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.</p>
<div class="news-date">Thu Apr 13 2006: </div> <p class="news-text"><a
href="@PACKAGE_URL@polypaudio-0.8.tar.gz">Version 0.8</a> released;
changes include: too many to count; many, many minor fixes.</p>
changes include: too many to count - consider reading <a href="http://0pointer.de/blog/projects/polypaudio-0.8.html">this blog entry</a> for more information; many, many minor fixes.</p>
<div class="news-date">Sun Nov 21 2004: </div> <p class="news-text"><a
href="@PACKAGE_URL@polypaudio-0.7.tar.gz">Version 0.7</a> released;
@ -152,6 +152,7 @@ available. A simple main loop implementation is available as well.</p>
<li><tt>module-lirc</tt>: a module to control the volume of a sink with infrared remote controls supported by LIRC.</li>
<li><tt>module-mmkbd-evdev</tt>: a module to control the volume of a sink with the special volume keys of a multimeda keyboard.</li>
<li><tt>module-zeroconf-publish</tt>: a module to publish local sources/sinks using mDNS zeroconf.</li>
<li><tt>module-rtp-send</tt>, <tt>module-rtp-recv</tt>: a module to implement RTP/SAP/SDP based audio streaming.</li>
</ul>
<p><tt>polypaudio</tt> is the successor of my previous, ill-fated

108
doc/modules.html.in
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@ -283,7 +283,7 @@ module and point your browser to <a
href="http://localhost:4714/">http://localhost:4714/</a>. This module takes the same arguments
as <tt>module-cli-protocol-tcp</tt>.</p>
<h2>Miscellaneous</h2>
<h2>X Window System</h2>
<h3>module-x11-bell</h3>
@ -315,6 +315,94 @@ and import credential data from/to the X11 display.</p>
cookie to store in the X11 display. If ommited the cookie of an
already loaded protocol module is used.</td></tr> </table>
<h2>Volume Control</h2>
<h3>module-mmkbd-evdev</h3>
<p>Adjust the volume of a sink when the special multimedia buttons of modern keyboards are pressed.</p>
<table>
<tr><td><tt>device=</tt></td><td>Linux input device ("<tt>evdev</tt>", defaults to <tt>/dev/input/event0</tt>)</td></tr>
<tr><td><tt>sink=</tt></td><td>The sink to control</td></tr>
</table>
<h3>module-lirc</h3>
<p>Adjust the volume of a sink when the volume buttons of an infrared remote control are pressed (through LIRC).</p>
<table>
<tr><td><tt>config=</tt></td><td>The LIRC configuration file</td></tr>
<tr><td><tt>appname=</tt></td><td>The application name to pass to LIRC (defaults to <tt>polypaudio</tt>)</td></tr>
<tr><td><tt>sink=</tt></td><td>The sink to control</td></tr>
</table>
<a name="rtp"/>
<h2>RTP/SDP/SAP Transport</h2>
<p>Polypaudio can stream audio data to an IP multicast group via the
standard protocols <a
href="http://en.wikipedia.org/wiki/Real-time_Transport_Protocol">RTP</a>,
<a
href="http://en.wikipedia.org/wiki/Session_Announcement_Protocol">SAP</a>
and <a
href="http://en.wikipedia.org/wiki/Session_Description_Protocol">SDP</a>
(RFC3550, RFC3551, RFC2327, RFC2327). This can be used for multiple
different purposes: for sharing a single microphone on multiple
computers on the local LAN, for streaming music from a single
controlling PC to multiple PCs with speakers or to implement a simple
"always-on" teleconferencing solution.</p>
<p>The current implementation is designed to be used exlusively in
local area networks, though Internet multicasting is theoretically
supported. Only uncompressed audio is supported, hence you won't be
able to multicast more than a few streams at the same time over a
standard LAN.</p>
<p>Polypaudio implements both a sender and a reciever for RTP
traffic. The sender announces itself via SAP/SDP on the same multicast
group as it sends the RTP data to. The reciever picks up the SAP/SDP
announcements and creates a playback stream for each
session. Alternatively you can use any RTP capable client to
recieve and play back the RTP data (such as <tt>mplayer</tt>).</p>
<h3>module-rtp-send</h3>
<p>This is the sender side of the RTP/SDP/SAP implementation. It reads
audio data from an existing source and forwards it to the network
encapsulated in RTP. In addition it sends SAP packets with an SDP
session description.</p>
<p>In combination with the monitor source of <tt>module-null-sink</tt>
you can use this module to create an RTP sink.</p>
<table>
<tr><td><tt>source=</tt></td><td>The source to read the audio data from. If ommited defaults to the default source.</td></tr>
<tr><td><tt>format=, rate=, channels=</tt></td><td>Sample format to use, defaults to the source's.</td></tr>
<tr><td><tt>destination=</tt></td><td>Destination multicast group for both RTP and SAP packets, defaults to <tt>224.0.0.56</tt></td></tr>
<tr><td><tt>port=</tt></td><td>Destination port number of the RTP
traffic. If ommited defaults to a randomly chosen even port
number. Please keep in mind that the RFC suggests to use only even
port numbers for RTP traffic.</td></tr>
<tr><td><tt>mtu=</tt></td><td>Maximum payload size for RTP packets. If ommited defaults to 1280</td></tr>
<tr><td><tt>loop=</tt></td><td>Takes a boolean value, specifying whether locally generated RTP traffic should be looped back to the local host. Disabled by default.</td></tr>
</table>
<h3>module-rtp-recv</h3>
<p>This is the reciever side of the RTP/SDP/SAP implementation. It
picks up SAP session announcements and creates an RTP playback stream
for each.</p>
<p>In combination with <tt>module-null-sink</tt> you can use this
module to create an RTP source.</p>
<table>
<tr><td><tt>sink=</tt></td><td>The sink to connect to. If ommited defaults to the default sink.</td></tr>
<tr><td><tt>sap_address=</tt></td><td>The multicast group to join for SAP announcements, defaults to <tt>224.0.0.56</tt>.</td></tr>
</table>
<h2>Miscellaneous</h2>
<h3>module-sine</h3>
<p>Creates a sink input and generates a sine waveform stream.</p>
@ -360,24 +448,6 @@ already loaded protocol module is used.</td></tr> </table>
<p>Publish all local sinks/sources using mDNS Zeroconf.</p>
<h3>module-mmkbd-evdev</h3>
<p>Adjust the volume of a sink when the special multimedia buttons of modern keyboards are pressed.</p>
<table>
<tr><td><tt>device=</tt></td><td>Linux input device ("<tt>evdev</tt>", defaults to <tt>/dev/input/event0</tt>)</td></tr>
<tr><td><tt>sink=</tt></td><td>The sink to control</td></tr>
</table>
<h3>module-lirc</h3>
<p>Adjust the volume of a sink when the volume buttons of an infrared remote control are pressed (through LIRC).</p>
<table>
<tr><td><tt>config=</tt></td><td>The LIRC configuration file</td></tr>
<tr><td><tt>appname=</tt></td><td>The application name to pass to LIRC (defaults to <tt>polypaudio</tt>)</td></tr>
<tr><td><tt>sink=</tt></td><td>The sink to control</td></tr>
</table>
<hr/>
<address class="grey">Lennart Poettering &lt;@PACKAGE_BUGREPORT@&gt;, April 2006</address>