path: root/interfaces.tex
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authorMatthias P. Braendli <matthias.braendli@mpb.li>2016-09-16 15:28:55 +0200
committerMatthias P. Braendli <matthias.braendli@mpb.li>2016-09-16 15:28:55 +0200
commitf0f355137eccb575a921b3155fb9f09ee3ff7f2b (patch)
tree997fa6a1e2bb71c5a83be7b8a97546384745b458 /interfaces.tex
parent555236b4d0319d233ac82941e87de327843e4305 (diff)
Replace FDK-AAC-DABplus and Toolame by ODR-AudioEnc
Diffstat (limited to 'interfaces.tex')
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:
- \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
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:
-toolame -b 128 prog1.wav prog1.mp2
+odr-audioenc --dab -b 128 prog1.wav prog1.mp2
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
-dabplus-enc -i prog2.wav -b 88 -o prog2.dabp
+odr-audioencenc -i prog2.wav -b 88 -o prog2.dabp
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}
-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:
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.