dabs

dabs is a DAB/DAB+ decoder. (Well, actually only DAB+.)

It uses an SDR (software-defined radio) device to receive data over the air transmitted by, well, a DAB/DAB+ emitter, and extracts audio content from it, playing it in your computer.

It supports USRP devices (I use a B210) and RTL-SDR devices.

Status: decodes local radio channels around Nice/France. May fail to work for other locations. Slow, basic documentation (README file).

Download

2025-07-05: git.tar.gz
To use:

mkdir /tmp/dabs
cd /tmp/dabs
wget http://sedcode.eu.org/dabs/git.tar.gz
tar xf git.tar.gz
rm git.tar.gz
git reset --hard

2025-07-05: dabs-2025-07-05.tar.bz2 [README]

Old releases

2023-01-27: dabs-1.1.tar.bz2
dabs-1.0.tar.bz2
dabs-0.9.tar.bz2
dabs-0.8.tar.bz2
dabs-0.7.tar.bz2
dabs-0.5.tar.bz2
dabs-0.5-pre1.tar.bz2
dabs-0.4.tar.bz2
dab-0.3.tar.bz2
dab-0.1.tar.bz2
dab-0.0.tar.bz2

Sample DAB+ data

Here is a DAB+ recording (format: IQ data, 16 bits for I, 16 bits for Q, little endian): rec-for-optim.raw The file is 131 MiB, will take some time to download.

Documentation

The specifications I used are:

ETSI EN 300 401: Radio Broadcasting Systems; Digital Audio Broadcasting (DAB) to mobile, portable and fixed receivers

ETSI TS 102 563: Digital Audio Broadcasting (DAB); DAB+ audio coding (MPEG HE-AACv2)

ETSI TS 101 756: Digital Audio Broadcasting (DAB); Registered Tables

I also found Introduction to DAB Receiver [source], which provided nice information.

As for websites, I looked at:

• worlddab.org for the specifications
• wikipedia about band 3 in France
• DAB Ensembles Worldwide for the available channels around me
• DAB radio design and implementation
• dsp.stackexchange.com for Carrier frequency offset (CFO) estimation using cyclic prefix (sorry for this link, it was very useful though)
• ML Estimation of Time and Frequency Offset in OFDM Systems
• wikipedia for Viterbi decoder (not very useful)
• The Viterbi Algorithm: A Personal History
• Error Bounds for Convolutional Codes and an Asymptotically Optimum Decoding Algorithm the article of Viterbi (I didn't understand a shit in there)
• Coding and decoding with convolutional codes.The Viterbi Algorithm not very clear either
• tutorial on Viterbi decoder definitely the best source of information for Viterbi decoding that I found! My brain can get the theoretical stuff, but if it's not backed by the correct intuition, I'm doomed, and this website gave me the correct intuition
• reed-solomon-WHP031.pdf was a good source to understand Reed-Solomon. I read some other documents, so maybe not enough by itself
• for Fire code I think the book Error Control Coding by Lin and Costello is a good source. The chapter 5 is what I implemented, especially 5.5. Fire codes are just a type of cyclic code that can be decoded with faster methods than the generic one for cyclic codes. It was not necessary to use a special method (and it did not work, I messed up somewhere), so I went the simple basic generic path. It's no big deal, works ok on my setup. Funny thing is we pickup the shortest error correction and apply it, but it may lead to incorrect decoded result, which I think is fine because later processing will reject the data. Or not... The book can be downloaded (as of 2025-07-05) on Anna's archive. If it fails for you, I can send a copy

Those links were functional 2021-09-07.

Related work

Free software for receiving DAB/DAB+

Here are some other implementations of DAB/DAB+ receiving. They are way more featured than mine.

• qt-dab (you can find dab-cmdline there as well) is the ultimate free software DAB/DAB+ receiver. Unfortunately I couldn't make it run on my system, too complex (seriously? Qt?). But I did read the code and without it my program would probably not exist.
• sdrangel (I could not find a proper website, sorry, github...) was the program I used to see that my local dumps were decodable! and so my program did not work. It's a nice GUI thing. For DAB/DAB+ it uses dab-cmdline code from what I understand.
• dablin was also a good source of information. I did not run the program, just read the source (the link is not to dablin itself but the, what, company? organization? making dablin, or distributing/maintening it, I don't really know). It was a good source of information too.

Those links were functional 2021-09-07.

There are surely others. This is what I found.

Free software for transmitting DAB/DAB+

There is a transmitting free software thing also, ODR mmbTools. Looks very complex to me, but they claim to be production ready, so, well, there it is. I didn't look at it, I simply know it exists.

This link was functional 2021-09-07.

I don't know of other transmitting DAB/DAB+ free software.

Contact: see this

Created: 2021-07-25
Last update: 2025-07-05