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Diffstat (limited to 'interfaces.tex')
| -rw-r--r-- | interfaces.tex | 15 |
1 files changed, 6 insertions, 9 deletions
diff --git a/interfaces.tex b/interfaces.tex index 512bde2..7d45c32 100644 --- a/interfaces.tex +++ b/interfaces.tex @@ -8,15 +8,15 @@ generate all files separately, one after the other. Here is an example to generate a two-minute ETI file for a multiplex containing two programmes: \begin{itemize} - \item one DAB programme at 128kbps, encoded with Toolame-DAB - \item one \dabplus{} programme at 88kbps, encoded with FDK-AAC-DABplus + \item one DAB programme at 128kbps + \item one \dabplus{} programme at 88kbps \end{itemize} We assume that the audio data for the two programmes is located in uncompressed 48kHz WAV in the files \filename{prog1.wav} and \filename{prog2.wav}. The first step is to encode the audio. The DAB programme is encoded to \filename{prog1.mp2} using: \begin{lstlisting} -toolame -b 128 prog1.wav prog1.mp2 +odr-audioenc --dab -b 128 prog1.wav prog1.mp2 \end{lstlisting} The DAB+ programme is encoded to \filename{prog2.dabp}. The extension @@ -24,7 +24,7 @@ The DAB+ programme is encoded to \filename{prog2.dabp}. The extension other AAC encoded audio, it makes sense to use a special extension. The command is: \begin{lstlisting} -dabplus-enc -i prog2.wav -b 88 -o prog2.dabp +odr-audioencenc -i prog2.wav -b 88 -o prog2.dabp \end{lstlisting} These resulting files can then be used with ODR-DabMux to create an ETI file. @@ -124,15 +124,12 @@ use this interconnection locally on the same machine. \subsubsection{Between Encoder and Multiplexer} \label{sec:between_encoder_and_multiplexer} -Between FDK-AAC-DABplus and ODR-DabMux, the ZeroMQ connection transmits AAC +Between ODR-AudioEnc and ODR-DabMux, the ZeroMQ connection transmits AAC superframes, with additional metadata that contains the audio level indication for monitoring purposes. The multiplexer cannot easily derive the audio level from the AAC bitstream without decoding it, so it 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. - On the multiplexer, the subchannel must be configured for ZeroMQ as follows: \begin{lstlisting} sub-fb { @@ -199,7 +196,7 @@ behaviour in intervals that are not acceptable, e.g. more than once per hour. Both situations are suboptimal, because they lead to audio glitches, and also degrade the ability to compensate for network latency changes. It is preferable -to use the drift compensation feature available in FDK-AAC-DABplus, which +to use the drift compensation feature available in ODR-AudioEnc, which insures that the encoder outputs the AAC bitstream at the 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. |