OFFgrid-SDR Updated to V2.1: Adds DAB, DAB+ and DRM xHE-AAC Decoding in the Browser
Back in October, we posted about OFFgrid-SDR, a fully offline RTL-SDR receiver program that runs in a WebUSB-compatible browser from a single index.html file. Richard Didd has now written in again to let us know that the project has passed 10,000 downloads and views, and that version 2.1 adds DAB, DAB+ and DRM digital radio support.
The DAB decoder is written in JavaScript directly from the standard, while DAB+ (HE-AAC) and original DAB (MP2) audio are decoded by FAAD2 and pl_mpeg compiled to WebAssembly. DRM also now supports xHE-AAC audio via Android's libxaac decoder. Richard tested DAB off-air on the BBC National DAB multiplex, but can't receive any xHE-AAC DRM stations from the UK, so reception reports from anyone in range would be welcome.
Richard also points out the AUTO mode, which listens to a signal for a couple of seconds, identifies it, and switches to the right mode or decoder. It recognizes CW, RTTY, PSK, NAVTEX, weather fax, SSTV, FT8/FT4/WSPR, ACARS, APRS, AIS, DRM and DAB, among others. OFFgrid-SDR is open source under the GPLv3 licence and available on GitHub, with more technical details in the Hackaday.io project log.
