From 7871f41f2e49978b8c5451516e7a464b0985828b Mon Sep 17 00:00:00 2001 From: Lennart Poettering Date: Sun, 16 Apr 2006 13:34:09 +0000 Subject: add documentation for the new RTP modules git-svn-id: file:///home/lennart/svn/public/pulseaudio/trunk@731 fefdeb5f-60dc-0310-8127-8f9354f1896f --- doc/FAQ.html.in | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 93 insertions(+), 4 deletions(-) (limited to 'doc/FAQ.html.in') diff --git a/doc/FAQ.html.in b/doc/FAQ.html.in index 0e738217..7adc2441 100644 --- a/doc/FAQ.html.in +++ b/doc/FAQ.html.in @@ -67,7 +67,7 @@ realtime, or increase the fragment sizes of the audio drivers. The former will allow Polypaudio to activate SCHED_FIFO high priority scheduling (root rights are dropped - immediately after this) Keep in mind that this is a potential security hole!

+ immediately after this). Keep in mind that this is a potential security hole!

  • The polypaudio executable is installed SUID root by default. Why this? Isn't this a potential security hole?

    @@ -103,7 +103,12 @@ in ~/.polypaudio/.

  • How do I use polypaudio over the network?

    -

    Just set $POLYP_SERVER to the host name of the polypaudio server.

    +

    Just set $POLYP_SERVER to the host name of the polypaudio +server. For authentication you need the same auth cookies on all sides. For +that copy ~./polypaudio-cookie to all clients that shall +be allowed to connect.

    + +

    Alternatively the authorization cookies can be stored in the X11 server.

  • Is polypaudio capable of providing synchronized audio playback over the network for movie players like mplayer?

    @@ -126,7 +131,7 @@ connect to a running polypaudio daemon try using the following commands:

    killall -USR2 polypaudio
 bidilink unix-client:/tmp/polypaudio/cli
    -

    BTW: Someone should package that great tool for Debian!

    +

    BTW: Someone should package this great tool for Debian!

    New: There's now a tool pacmd that automates sending SIGUSR2 to the daemon and running a bidilink like tool for you.

    • @@ -146,7 +151,91 @@ bidilink unix-client:/tmp/polypaudio/cli

  • Why the heck does libpolyp link against libX11?

    -

    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.

    • +

    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.

    + +

  • How can I use Polypaudio as an RTP based N:N multicast +conferencing solution for the LAN?

    After loading all the +necessary audio drivers for recording and playback, just load the RTP +reciever and sender modules with default parameters:

    + +
    +load-module module-rtp-send
+load-module module-rtp-recv
+
    + +

    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 rate=8000 format=ulaw channels=1 to the +sender module to save bandwith while still maintaining good quality +for speech transmission.

    • + +

  • What is this RTP/SDP/SAP thing all about?

    + +

    RTP is the Realtime Transfer Protocol. It is a well-known +protocol for transferring audio and video data over IP. SDP is the Session +Description Protocol and can be used to describe RTP sessions. SAP +is the Session Announcement Protocol 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)

    + +

    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.

    + +

    For more information about using these technologies with Polypaudio have a look on the respective module's documentation. + +

  • How can I use Polypaudio to stream music from my main PC to my LAN with multiple PCs with speakers?

    + +

    On the sender side create an RTP sink:

    + +
    +load-module module-null-sink sink_name=rtp
+load-module module-rtp-send source=rtp_monitor
+set-default-sink rtp
+
    + +

    This will make rtp the default sink, i.e. all applications will write to this virtual RTP device by default.

    + +

    On the client sides just load the reciever module:

    +
    +load-module module-rtp-recv
+
    + +

    Now you can play your favourite music on the sender side and all clients will output it simultaneously.

    + + +

    BTW: You can have more than one sender machine set up like this. The audio data will be mixed on the client side.

    • + +

  • How can I use Polypaudio to share a single LINE-IN/MIC jack on the entire LAN?

    + +

    On the sender side simply load the RTP sender module:

    + +
    +load-module module-rtp-send
+
    + +

    On the reciever sides, create an RTP source:

    + +
    +load-module module-null-sink sink_name=rtp
+load-module module-rtp-recv sink=rtp
+set-default-source rtp_monitor
+
    + +

    Now the audio data will be available from the default source rtp_monitor.

    + +

  • When sending multicast RTP traffic it is recieved on the entire LAN but not by the sender machine itself!

    + +

    Pass loop=1 to the sender module!

    • + +

  • Can I have more than one multicast RTP group?

    + +

    Yes! Simply use a new multicast group address. Use +the destination/sap_address arguments of the RTP +modules to select them. Choose your group addresses from the range +225.0.0.x to make sure the audio data never leaves the LAN.

    • -- cgit