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> DAB was implemented using the old MPEG2 audio codec. No, it was MPEG 1 layer 2 often at 192 kbps. Later they switched to HE-AAC with DAB+.

by dotwaffle2 hours ago|

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DAB+ uses EEP (and RS) which was deliberately chosen to give better signal quality all the way to the point of losing reception. Old DAB used UEP which degrades faster, but instead of having no signal, it went to a muddier / warbling kind of sound that characterised early DAB receivers.

And technically while some people do call it MPEG2, it's actually MP2, also known as MPEG-1 Audio Layer 2, an audio codec in the same family as MP3 (MPEG-1 Audio Layer 3).

I imagine that today they'd probably use something like Opus and a fountain code or similar, yes... But you can't expect everyone to replace their radio every 10-15 years ;)

by cogman101 hours ago|

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> I imagine that today they'd probably use something like Opus and a fountain code or similar, yes... But you can't expect everyone to replace their radio every 10-15 years ;)

Certainly not, which is why I believe DAB (no plus) is still floating around. And I'm not really suggesting that they made a bad choice.

I'm mostly pushing back on the notion that digital means all or nothing audio. If broadcast audio stays alive (which it may not) then I hope the next standard is opus, fountain codes, and QAM-64 or similar so we can stuff a bunch of bits into error correction while still having graceful degradation, better than analog, when the signal degrades.

by dotwaffle1 hours ago|

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I could be wrong, but I think DAB uses DQPSK (which can be thought of as a special version of QAM 4 if you squint a bit) and not anything like the higher QAM constellations because it's deliberately designed for mobile (road, train etc) where you don't have a steady signal, it can vary a lot with motion, so QAM 64 wouldn't really be possible.

Though I did a quick check and apparently DRM+ uses QAM-16, so perhaps my knowledge is far too out of date :S

by cogman101 hours ago|

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LTE and 5g both use QAM 256 and higher. Wifi 7 can use QAM 4096 (though not a lot of motion there).