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author | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-12-11 17:57:48 +0100 |
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committer | Matthias P. Braendli <matthias.braendli@mpb.li> | 2014-12-11 17:57:48 +0100 |
commit | 50cc2b0dcceff73b5f86690f0f442e75efaf3d21 (patch) | |
tree | 5bb5d4127b8150e4454fa2a66257dba41522a19a /interfaces.tex | |
parent | bc563e8e332010768f89370f3c3b4cddffaa9d8a (diff) | |
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Add interface and scenario text
Diffstat (limited to 'interfaces.tex')
-rw-r--r-- | interfaces.tex | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/interfaces.tex b/interfaces.tex index a008819..ef8fb71 100644 --- a/interfaces.tex +++ b/interfaces.tex @@ -1,5 +1,6 @@ \section{Interfacing the Tools} \subsection{Files} +\label{sec-files} The first versions of these tools used files and pipes to exchange data. For offline generation of a multiplex or a modulated I/Q, it is possible to generate all files separately, one after the other. @@ -111,6 +112,10 @@ This network connection is based on ZeroMQ, a library that permits the creation connection with automatic connection management (connection, disconnection, error handling). ZeroMQ uses a TCP/IP connection, and can therefore be used over any kind of IP networks. +This connection makes it possible to put the different tools on different computers, but it is not +necessary. It is also possible, and even encouraged to use this interconnection locally on the same +machine. + \subsubsection{Between Encoder and Multiplexer} Between fdk-aac-dabplus and ODR-DabMux, the ZeroMQ connection transmits AAC superframes, with @@ -121,8 +126,6 @@ makes more sense to calculate this in the encoder. The toolame-dab encoder also can send MPEG frames over ZeroMQ, but is not yet able to calculate and transmit audio level metadata yet. -\sidenote{Add configuration example for encoders} - On the multiplexer, the subchannel must be configured for ZeroMQ as follows: \begin{lstlisting} sub-fb { @@ -186,7 +189,7 @@ available in fdk-aac-dabplus, which insures that the encoder outputs the AAC bit nominal rate, aligned to the NTP-synchronised system time, and not to the sound card clock. The sound card clock error is compensated for inside the encoder. - +Complete examples of such a setup are given in the Scenarios. \subsubsection{Authentication Support} In order to be able to use the Internet as contribution network, some form of protection has to be @@ -207,4 +210,15 @@ to set up keys and to distribute them to the encoder and the multiplexer. \subsubsection{Between Multiplexer and Modulator} +The ZeroMQ connection can also be used to connect ODR-DabMux to one or more instances of ODR-DabMod. +One ZeroMQ frame contains four ETI frames, which guarantees that the modulator always assembles the +transmission frame in a correct way, even in Transmission Mode I, where four ETI frames are used +together. + \subsection{Pipes} + +Pipes are an older real-time method to connect several encoders to one multiplexer on the same +machine. It uses the same configuration as the file input but instead of using files, FIFOs, also +called ``named pipes'' are created first using \texttt{mkfifo}. + +This setup is deprecated in favour of the ZeroMQ interface. |