fdk-aac-dabplus

A standalone library of the Fraunhofer FDK AAC code from Android, patched for 960-transform. Used for DAB+ broadcast encoding.

Also includes a version with a ODR-DabMux compatible ZeroMQ output.

There is experimental support for DAB MOT Slideshow and DLS, written by CSP http://rd.csp.it

Usage:

aac-enc-dabplus [OPTION...]

-b, --bitrate={ 8, 16, ..., 192 }    Output bitrate in kbps. Must be multiple of 8.
-i, --input=FILENAME                 Input filename (default: stdin).
-o, --output=FILENAME                Output filename (default: stdout).
-a, --afterburner                    Turn on AAC encoder quality increaser.
-f, --format={ wav, raw }            Set input file format (default: wav).
-c, --channels={ 1, 2 }              Nb of input channels for raw input (default: 2).
-r, --rate={ 32000, 48000 }          Sample rate for raw input (default: 48000).

The encoder with ZeroMQ output has the same options as above, but takes a zmq destination url as output

See aac-enc-dabplus-zmq -h

How to build

Requirements: * boost-thread and boost-system * ImageMagick magickwand (for MOT slideshow)

Download code and unpack it.
Download and install libfec from https://github.com/Opendigitalradio/ka9q-fec
do "./configure", then "make" and "make install"
use aac-enc-dabplus or aac-enc-dabplus-zmq to encode live stream or file.
use mot-encoder to encode images into MOT Slideshow

How to use

Scenario 1

Live Stream encoding and preparing for DAB muxer, with ZMQ output, at 32kHz, using sox.

ALSASRC="default"
DST="tcp://yourserver:9000"
BITRATE=64

sox -t alsa $ALSASRC -b 16 -t raw - rate 32k channels 2 | \
../fdk-aac-dabplus/aac-enc-dabplus-zmq -r 32000 \
-i /dev/stdin -b $BITRATE -f raw -a -o $DST -p 4

Scenario 2

Live Stream encoding and preparing for DAB muxer, with FIFO to odr-dabmux, 48kHz, using arecord.

arecord -t raw -f S16_LE -c 2 -r 48000 -D plughw:CARD=Loopback,DEV=0,SUBDEV=0 | \
aac-enc-dabplus -b 24 -f raw -c 2 -r 48000 -i /dev/stdin -o /dev/stdout 2>/dev/null | \
mbuffer -q -m 10k -P 100 -s 360 > station1.fifo

Scenario 3

Wave file encoding, for non-realtime processing

aac-enc-dabplus -a -b 64 -i wave_file.wav -o station1.dabp

Usage of MOT Slideshow

MOT Slideshow is an experimental feature. The mot-encoder reads images in the specified folder, and generates the PAD data for the encoder. This is communicated through a unique fifo in /tmp, therefore only one instance can run on a single machine.

Only aac-enc-dabplus-zmq inserts the PAD data from mot-encoder into the bitstream.

This is an ongoing development.