FDK-AAC-DABplus

Revision as of 18:50, 11 September 2013

Installation

This is open-source version of DAB+ encoder.

To build DAB+ encoder, you need fec library from crc.ca website: http://mmbtools.crc.ca/content/view/39/65/, follow instrutcions to install it to the system. If you already build crc-dabmux from sources, then this library is already installed. Next, download and build encoder:

git clone https://github.com/piratfm/fdk-aac-dabplus.git
cd fdk-aac-dabplus
./bootstrap
./configure --enable-example
make
sudo make install

Encoding samples

After successful installation, DAB+ encoding may be used:

Live Stream enconding and preparing for DAB mux:

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

Wave file enconding and preparing for crc-dabmux:

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

Problems solving

If crc-dabmux generates lot of errors like this:

<2> ERROR: Incomplete DAB+ frame! 136 != 360
<5> reach end of file -> rewinding
<2> ERROR: Can't rewind file
<6> ETI frame number: 228

Then the stream have to be buffered before giving it to muxer, this additional buffer installed between encoder and fifo. To calculate proper block size for mbuffer ("-s" parameter), the table below may be used:

In example above, for stream with bitrate 24 kbps, mbuffer size setted to 360 bytes. This trick helping to solve problem.