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Old 7th May 2022, 14:28   #1  |  Link
FranceBB
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DAB with poor bitrate across the world?

Hi there,
a few days ago I was discussing with Derek (Blue_MiSfit) about where the radio is going. Sure, we're on Doom9, we all care about encoding etc, but you gotta admit that every once in a while when we're commuting we listen to radio and... I found the situation to be sub optimal, which led me to open this topic.
Leaving aside Italy that still lives with analog frequency modulation as if time didn't pass and knows nothing about digital radio, in the UK DAB and DAB+ are pretty much widespread, but... at very poor bitrates, which sort of bothers me.
Although AAC is a very good codec, there's a limit to what it can do, no matter how good the encoder is or what "tricks" are used (like the roll-off of some frequencies before encoding etc).
In this case, I'm gonna take the direct stream dump of Capital London, one of my favorite radio stations as I listen to Capital Breakfast with Roman Kemp, Sonny Jay and Sian Welby every morning as I wake up and on my way to work.

This is stream dump: https://we.tl/t-ghBht5R5X5
And this is the web equivalent of the DAB stream: http://media-the.musicradio.com/Capital?type=.flv

as you can see from Mediainfo:

Quote:
General
Complete name : /home/FranceBB/Downloads/file.aac
Format : ADTS
Format/Info : Audio Data Transport Stream
File size : 2.19 MiB
Overall bit rate mode : Variable

Audio
Format : AAC LC SBR
Format/Info : Advanced Audio Codec Low Complexity with Spectral Band Replication
Commercial name : HE-AAC
Format version : Version 4
Format settings : Implicit
Codec ID : 2
Bit rate mode : Variable
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 44.1 kHz
Frame rate : 21.533 FPS (2048 SPF)
Compression mode : Lossy
Stream size : 2.19 MiB (100%)
it's an HE-AAC at 48 kbit/s VBR with some occasional spikes at 49-50 kbit/s up and down to 46-47 kbit/s.
If we use the Brown-Puckette Q Transform to view the frequency spectrum represented logarithmically with direct frequency domain coefficient calculation to show musical tone scale, from E0 to D#10, we can see that anything past A9 is cut off:




which is a shame, really.
So my question is: what's the situation where you live? Are we really going forward in the right way with DAB/DAB+? What's the HE-AAC bitrate of your favorite radio station and what do you think about radios in general? Are you an audiophile who only always listens to PCM lossless or do you sometimes listen to the radio as well?
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Old 7th May 2022, 14:43   #2  |  Link
nevcairiel
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We have a few stations around here broadcasting with up to 144kbit, all in AAC-HEv2 of course. Quality varies where you are, and which stations you listen to, which goes down to 40kbps for some of them, although the average appears to be much higher, between 72 and 96.

Of course all of that is AAC-HEv2, which means Spectral Band Replication is in use, which sacrifices spectral detail for compression gains.
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Old 7th May 2022, 16:23   #3  |  Link
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O.T,
I've recently just got a DAB portable radio [small cheap] LogiK something or other,
and because of lack of DAB+, also then got a AZATOM Pro Sports 2 DAB/DAB+ pocket thingy.
I've never owned a DAB radio before, and as I dont have a TV, I dont have access to EPG for DAB channels. [I think they exist in UK FreeView DVB transport streams].
On thinking about how to get EPG, I decided maybe I get an SDR (Software Defined Radio, only mentioned on D9 once, more than a decade ago, I think).
Anyways, was wondering if you use SDR at all, for EPG.
The Pocket DAB+ I got is a bit tinny sounding, but I only really want it for news channels or eg World Service.
EDIT: SDR/DVB transport stream EPG (and associated streams) should also provide bit rate etc. [EDIT: This line is On Topic]

EDIT: Look up SDR on YouTube, seems to be incredibly flexible, and cheap. [SDR on YouTube:- https://www.youtube.com/results?search_query=sdr ]

EDIT: Just did a google search on
Code:
"software defined radio" Site:forum.doom9.org
and got 5 hits from that
https://www.google.co.uk/search?q=%2...client=gws-wiz

EDIT:
A popular SDR on Amazon, with lots of addon bits [62.99-might find it cheaper]:- https://www.amazon.co.uk/RTL-SDR-RTL...s%2C618&sr=8-3
Nearly all available SDR sofware is open source. [I'm not yet aware of any that is not Open Source]
EDIT: Can also access simulated SDR using freely exposed SDR from open SDR stations around the world, using only web browser, or scanner software connected to WEB based SDR via the internet.
[I guess I could access EPG via one of those in the uk, also could inquire DAB+ bitrates etc in other parts of the world]
EDIT: Eg, without your own SDR, can listen to non encrypted channels live from the Ukraine,
or, lookup info about the airplane flying over your head, or view live pics from the International Space Station.
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Old 7th May 2022, 19:04   #4  |  Link
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Quote:
Originally Posted by FranceBB View Post
.......
So my question is: what's the situation where you live? Are we really going forward in the right way with DAB/DAB+? What's the HE-AAC bitrate of your favorite radio station and what do you think about radios in general? Are you an audiophile who only always listens to PCM lossless or do you sometimes listen to the radio as well?
Here in Brazil there exists no digital radio broadcast -.-
Analog AM (including the shortwave frequencies) and analog FM are all that is.
The only "digital radio stations" are the web sites which stream (the so-called) "HD-Audio" through HTTP.
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Old 7th May 2022, 20:13   #5  |  Link
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Quote:
Originally Posted by nevcairiel View Post
We have a few stations around here broadcasting with up to 144kbit, all in AAC-HEv2 of course.
Well at least 144 kbit/s is definitely something you can listen to, though, unlike the very low bitrate I showed above.

Quote:
Originally Posted by nevcairiel View Post
Of course all of that is AAC-HEv2, which means Spectral Band Replication is in use, which sacrifices spectral detail for compression gains.
Yeah...

Quote:
Originally Posted by filler56789 View Post
Here in Brazil there exists no digital radio broadcast -.-
Analog AM (including the shortwave frequencies) and analog FM are all that is.
The only "digital radio stations" are the web sites which stream (the so-called) "HD-Audio" through HTTP.
So it's like in Italy ehehehehe

Quote:
Originally Posted by StainlessS View Post
The Pocket DAB+ I got is a bit tinny sounding, but I only really want it for news channels or eg World Service.
Of course you want it for news channels, as an "old fart" you're probably listening to LBC and/or BBC while "youngsters" are more Capital oriented ehehehehe

("old fart" is intended as the recurring generational joke we make to each other when we post on this forum and has no offensive acception whatsoever as you're one of the oldest members I like to talk to most)

Speaking of which, I'm gonna be at the Capital Summertime Ball at Wembley this summer, just like I've been to the Jingle Bell Ball last December at the O2.

Last edited by FranceBB; 7th May 2022 at 20:15.
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Old 7th May 2022, 22:16   #6  |  Link
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In Poland move to DAB+ is very "slow". For years we have MUXes with Poland national radio channels. Bitrate is 64 kbit/s for more talking oriented channels to 112 kbit/s and seems to be AAC-HEv1. But it varies by region.

But biggest commercial stations are still in analog and they seem to be focusing on expanding to internet radio instead.
Quote:
The position of the RMF Group towards DAB+ has not changed for years: it is an old, ineffective system, which does not provide the listener with additional benefits and is very expensive.
[...]
Representatives of Eurozet speak in a similar vein. They point out that digitization via the Internet is a better model.
(from some article from 12.2021 about slots distribution on new muxes)
I don't track the political side of this... There are plans now to expand, but not yet sure who will "win" muxes to put their stations. but overall there is no much interest in DAB tbh...

An the other topic, we are moving to DVB-T2 (from T) this year. Not sure much (younger) people watches it though, in times of VOD platforms. Maybe for sport events.

Quote:
Originally Posted by StainlessS View Post
Nearly all available SDR sofware is open source. [I'm not yet aware of any that is not Open Source]
The most popular SDRSharp on Windows is closed source and not that good for it's popularity. I like https://github.com/f4exb/sdrangel but there is very big fragmentation of software/tools, depending what you want to do. All in all for very cheap you can get a nice toy to play with. But let stop offtopic here

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Old 9th May 2022, 14:04   #7  |  Link
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I think the real way going forward is FLAC podcasts. Like this one. MQA inside flac audio is also good, radio paradise does support that as well. Here, click on settings--> flac https://radioparadise.com/player/inf...n_Waves/Repaid

Or direct link https://stream.radioparadise.com/flac
Sdr# was open source for a very long time. Anyway, it is much worse than gnuradio. After all, it is insanely complicated to correctly decode (W)FM or mono FM... look into this! https://github.com/gnuradio/gnuradio/pull/3991

As for Mondial+ http://dabmonitor.nl/ does real time DAB+ HE-AACv2, but it uses 960 by default, which is not supported by ffmpeg yet. Only v1 /960 is supported. https://trac.ffmpeg.org/ticket/1407

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Old 9th May 2022, 16:00   #8  |  Link
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Quote:
Originally Posted by nevcairiel View Post
We have a few stations around here broadcasting with up to 144kbit, all in AAC-HEv2 of course...
Hmmm...

Isn't it the case that all HE-AAC v2 content is encoded with parametric stereo?
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Old 9th May 2022, 21:13   #9  |  Link
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HE-AAC v2 means SBR + PS (Parametric Stereo) and the recommended average bitrate is less than 48 Kb/s, for bitrates less than 96 only SBR (Spectral Band Replication) HE-AAC, with more bitrate is better AAC-LC without PS and SBR.

AAC-HE v2 can't have bitrates of 144 Kb/s. That bitrate is recommended for stereo AAC-LC or multichannel AAC-HE (AAC-HE v2 can't be multichannel)

The sample in first post is a AAC-HE with a Variable BitRate min./avg./max. : 37 / 47 / 72 Kb/s (low quality)
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Old 26th May 2022, 03:24   #10  |  Link
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Futher to my supposed O.T. @ post #3, here is a DAB scan including BitRates for about 100+ DAB/+ stations in London (via RTL-SDR, Software Defined Radio) in CSV format (11KB).
https://www.mediafire.com/file/818it...-2022.csv/file
EDIT: Source of csv, qt-dab-4.351:- https://github.com/JvanKatwijk/qt-dab
EDIT: Qt-Dab User Manual:- https://github.com/JvanKatwijk/qt-da...ocs/manual.pdf

No idea what I'm doing yet, but is sorta working OK.

EDIT: On qwik inspection, BBC Radio 3 seems to be the only one @ 192 Kb/s (old DAB), and maybe a dozen and a half @ 32Kb/s(DAB+), and several @ 24Kb/s(DAB+) ,
time for bed.

EDIT:
A little bit as Image. ClickMe twice


EDIT: At a guess, 'BBC GUIDE' is either EPG, or more likely the service that describes all the other services, maybe.

EDIT:
Quote:
Originally Posted by FranceBB View Post
("old fart" is intended as the recurring generational joke we make to each other when we post on this forum and has no offensive acception whatsoever as you're one of the oldest members I like to talk to most)
You Think !, impudent young pup.

EDIT: Maybe the last two in image (Capital and Heart, repeats of earlier stations) are from adjacent area transmitters (auto switchover for mobile receivers).
EDIT: Or, just some extra data streams associated with those particular radio stations. [station logo or something]
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Old 26th May 2022, 15:39   #11  |  Link
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For anyone interested...

A list of the current 18No UK DAB multiplexes/blocks (along with their frequencies) can be found here: https://en.wikipedia.org/wiki/Digita...frequency_plan
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Old 26th May 2022, 17:00   #12  |  Link
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It is my understanding that bitRate and quality of Digital Terrestial TV radio channels, is higher than that of DAB/+ radio.

EDIT: Back in early 2000's, I was doing a short electronics course, and in an hour or so, knocked up a sorta AM crystal radio set (just knocked up what I thought might work, using a variable capacitor from an old transistor radio, and about a 60 foot antenna {bit of wire}), and managed to pick up a single station, speaking [very very faint] in some kind of Indian lingo (maybe Urdu, Hindi, or something).
I was overjoyed as I thought I had picked up a signal from a distant continent. Alas, turned out was some Indian radio station broadcast from a mile or two up the road.

EDIT:
Quote:
Originally Posted by kasper93 View Post
The most popular SDRSharp on Windows is closed source and not that good for it's popularity. I like https://github.com/f4exb/sdrangel but there is very big fragmentation of software/tools, depending what you want to do. All in all for very cheap you can get a nice toy to play with.
Thanx, I'll give SdrAngel a bash.
Nearly broke my RTL-SDR already [only got it yesterday, 9 day delivery from USA], tripped over the damn antenna wire and bent the USB type A connector, now juts out at about 20 [EDIT: 15] degrees off intended.
EDIT: Think I'll hav'ta use a short, 9 inch USB extension with it, so that it has a 'straight pull out' separation when I next trip over the damn thing.
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Old 27th May 2022, 12:24   #13  |  Link
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Quote:
Originally Posted by StainlessS View Post
It is my understanding that bitRate and quality of Digital Terrestial TV radio channels, is higher than that of DAB/+ radio.
The bit-rate could well be higher but, from what I remember, the audio format is still crappy old MPEG-2 Layer-2 (MP2) here in the UK.

There must be somewhere on the internet to confirm the current 'radio' audio format types for both DVB-T and DVB-S...
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Old 27th May 2022, 16:26   #14  |  Link
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My DAB vs DVB-T thingy was based on taking a look at DVB-t docs and how it worked, about 12 -> 15 years ago, not DVB-T2 nor DAB+.
(and as I dont have TV, have no real experience of DVB-T audio)

But, here a google Search, might show up some stuff for those interested [I had not read much of it].
[links have to reference both "DAB" AND "DVB-T" {both enclosed in dQuotes} : links having 'vs' ie versus/comparing, are sorted earlier in list of links]
Code:
"DAB" vs "DVB-t" audio
https://www.google.co.uk/search?q=%2...client=gws-wiz

Just links from the UK,
Code:
"DAB" vs "DVB-t" audio site:.co.uk
https://www.google.co.uk/search?q=%2...client=gws-wiz

Just from D9,
Code:
"DAB" vs "DVB-t" audio site:forum.doom9.org
https://www.google.co.uk/search?q=%2...client=gws-wiz

@ Video Help whole site [or site:forum.videohelp.com for forum only]
Code:
"DAB" vs "DVB-t" audio site:videohelp.com
https://www.google.co.uk/search?q=%2...client=gws-wiz

Maybe try targetting an audio specific site.
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Old 28th May 2022, 00:19   #15  |  Link
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Thanks for the list of the channels and the bitrate, StainlessS!
What I found interesting is that you picked up capital as DAB AAC 128 kbit/s and I picked it up as HE-AAC SBR 64 kbit/s, which is the sample I shared above. Maybe they have different bitrate for different regions. Their "HD" internet streaming seems to be similar to the stream I picked, so around 44 kbit/s - 68 kbit/s and I can definitely tell the artifacts. BBC radio stations also seem to be the ones with the highest bitrate, however they're not exactly playing the tunes I like...

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Nah, deep down I know you like my company here on Doom9 xD

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Old 28th May 2022, 18:12   #16  |  Link
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Quote:
Nah, deep down I know you like my company here on Doom9 xD
Yep, tis one of the joys of my life

@SeeMoreDigital,
Tried SdrAngel, for some reason the 'floating hints' (forgot what they are called) that hover over a button when you pass a mouse over them, stopped working,
and now the window is unsizable, and non closable, and mostly blank except for title bar, I have to reboot to get rid of it.
Re-install makes no difference, so I guess I gotta refresh from a W10 image from some months ago.
SdrAngel is current one from yesterday, I think.
Anyways, I just downed DragonOS in the pub, [EDIT: ~4GB], which is [EDIT: Debian based] SDR specific version of linux, with bucket loads of SDR stuff.
[I'll install DragonOS on a separate drive and boot from USB 3.x HDV dock - Best do install with SSD and other drives disabled, so as to be bootable without needing current boot set up, and/or OS's]
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Old 29th May 2022, 11:53   #17  |  Link
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With regard to ascertaining the audio format and bit-rates for the various DVB-T and DAB radio stations...

I guess the easiest way would be to buy something like this USB2.0 DVB-T SDR+DAB+FM TV HDTV dongle. And download a few seconds of audio from each radio station and compare them
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Old 29th May 2022, 12:26   #18  |  Link
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Just a note on that, Starworld Digital USB2.0 DVB-T SDR+DAB+FM TV HDTV Tuner Receiver Stick RTL2832U+R820T
Quote:
Support Windows 2000/XP/Vista/WIN7 and both MPEG-2, MPEG-4(H.264) encoding;
If supports W2K, then cannot be BDA (Broadcast Driver Architecture) driver,
BDA (1st implemented in XP), allowed DVB-T TV viewing software to work with different USB dongles,
if supports W2K, then driver and software non BDA, and specific to only that USB device.
(of course, it is possible that device seller is being 'optimistic' about it working under W2K)

EDIT: Also possible that a separate driver is supplied for non BDA W2K.
Also, BDA allowed you to use other BDA compliant TV viewer software with any BDA dongle.

EDIT: Seems that above is total sh1t, according to Wikipedia, BDA was implemented in W98.
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