German radio migrating to AAC on 19.2E

[Arcy]

An upheaval in German public radio on 19.2E is taking place this month, with a move from mp2 and AC3 encoding to a new transponder with AAC-HE encoding (although the relevant web pages call it AAC-LC). With the accompanying reduction in bit rates (from 320 Kbit/s to 160 or 256 kbit/s for stereo, and -- by the look of it -- 448 kbit/s to 320 kbit/s for surround), the change will free a transponder for other uses. The old services are to be discontinued on July 20.

However, I'm wondering what's going to happen to the surround sound (5.0 and 5.1) broadcasts from these stations. Because of Covid, there aren't many of them just at the moment, but one was carried yesterday afternoon by BR-Klassik -- a station which for some years has provided AC3 and mp2 streams in parallel, even when in plain stereo. However, when I checked its new transponder, I found that both audio streams were in stereo only -- though one was at 160 kbit/s and the other at 320 kbit/s.

Could this be because the engineers hadn't finished plugging up the network? Or is it more likely that not all DVB receivers can process multichannel AAC? Since the only surround transmissions I've met up to now have been in AC3 or AC-3+, I've no way of telling. But the surround-sound broadcasts from Germany are a stunning experience, and I would rather not lose them.

[ronand]

Multichannel AAC is a problem for a lot of STBs - I don't think I've had one that can play it. Its a pity because it should be higher quality than AC3. I would choose 2 channel Mpeg over 6 channel AC3 given the choice.

[Arcy]

I would choose 2 channel Mpeg over 6 channel AC3 given the choice.
Up to now, we have had that choice with German radio. Myself, I've no complaints about 5.0 sound at 448 kbit/s (which is more than the BBC offers, even on TV). And they certainly know how to do a music balance over there.

[Arcy]

I've at last got found a solution to this problem, using a GigaBlue UHD Quad 4K. In its Video & Audio Settings menu, AAC Downmix must be set to Passthrough -- but in addition, PCM Multichannel must be set to Yes. If you then tune to BR-Klassik (12265 MHz H, 19.2°E) and use the Audio button on the remote control to select AAC-HE Surround, you should hear the test stream, a recording of Beethoven's Leonora No 3 overture in 5.0 sound on a loop -- either that or an actual broadcast.

The two other receivers I've been able to try don't do this. My Vu+ Solo 4K has a shorter Video & Audio Settings menu which does not in include the PCM Multichannel setting. Its Audio button brings up the AAC-HE Surround stream option, but selecting it produces only silence. On the Octagon SF4008, the Video & Audio Settings menu is even shorter -- it does not have an AAC setting, although the receiver happily plays the AAC stereo sound on French TV channels and Hungarian radio. If I select the AAC-HE Surround stream on BR-Klassik, it plays, but only as a stereo mixdown.

All these receivers are running OpenVIX v5.4.016.

Presumably there are other receivers which can play AAC surround correctly, but I can see no obvious way of knowing which.

[twol]

I've at last got found a solution to this problem, using a GigaBlue UHD Quad 4K. In its Video & Audio Settings menu, AAC Downmix must be set to Passthrough -- but in addition, PCM Multichannel must be set to Yes. If you then tune to BR-Klassik (12265 MHz H, 19.2°E) and use the Audio button on the remote control to select AAC-HE Surround, you should hear the test stream, a recording of Beethoven's Leonora No 3 overture in 5.0 sound on a loop -- either that or an actual broadcast.

The two other receivers I've been able to try don't do this. My Vu+ Solo 4K has a shorter Video & Audio Settings menu which does not in include the PCM Multichannel setting. Its Audio button brings up the AAC-HE Surround stream option, but selecting it produces only silence. On the Octagon SF4008, the Video & Audio Settings menu is even shorter -- it does not have an AAC setting, although the receiver happily plays the AAC stereo sound on French TV channels and Hungarian radio. If I select the AAC-HE Surround stream on BR-Klassik, it plays, but only as a stereo mixdown.

All these receivers are running OpenVIX v5.4.016.

Presumably there are other receivers which can play AAC surround correctly, but I can see no obvious way of knowing which.
I have no issue playing this service on my Zgemma receivers as well the Giga4K. Interestingly, the h9combo offers HE-stereo and HE- surround

[Arcy]

I have no issue playing this service on my Zgemma receivers as well the Giga4K. Interestingly, the h9combo offers HE-stereo and HE- surround

That's useful information -- thank you. However, it's puzzling that all these receivers report the audio mode as AAC-HE when the ARD sources say it's AAC-LC.
https://www.br.de/unternehmen/inhalt/technik/rundfunktechnik-radio-satellit100.html

[nekrub2]

Thanks for the notice of the transponder change. I manually searched for the new transponder and could update my favourites. As I have no surround but downmix AAC I get my 2-channel stereo sound.

[Huevos]

I've at last got found a solution to this problem, using a GigaBlue UHD Quad 4K. In its Video & Audio Settings menu, AAC Downmix must be set to Passthrough -- but in addition, PCM Multichannel must be set to Yes. If you then tune to BR-Klassik (12265 MHz H, 19.2°E) and use the Audio button on the remote control to select AAC-HE Surround, you should hear the test stream, a recording of Beethoven's Leonora No 3 overture in 5.0 sound on a loop -- either that or an actual broadcast.

The two other receivers I've been able to try don't do this. My Vu+ Solo 4K has a shorter Video & Audio Settings menu which does not in include the PCM Multichannel setting. Its Audio button brings up the AAC-HE Surround stream option, but selecting it produces only silence. On the Octagon SF4008, the Video & Audio Settings menu is even shorter -- it does not have an AAC setting, although the receiver happily plays the AAC stereo sound on French TV channels and Hungarian radio. If I select the AAC-HE Surround stream on BR-Klassik, it plays, but only as a stereo mixdown.

All these receivers are running OpenVIX v5.4.016.

Presumably there are other receivers which can play AAC surround correctly, but I can see no obvious way of knowing which.

Check you have the latest build loaded on the boxes where PCM Multichannel is missing as it was only fixed recently. But anyway some boxes don't have that option in the drivers.

[BrokenUnusableAccount]

That's useful information -- thank you. However, it's puzzling that all these receivers report the audio mode as AAC-HE when the ARD sources say it's AAC-LC.

Maybe the labelling just lumps it all together.
AIUI an AAC-HE decoder will happily decode an AAC-LC stream. That certainly how it used to be anyway, but there does seem to be more variations on AAC now than there used to be.

[BrokenUnusableAccount]

Up to now, we have had that choice with German radio. Myself, I've no complaints about 5.0 sound at 448 kbit/s (which is more than the BBC offers, even on TV). And they certainly know how to do a music balance over there.

I've watched films on BBC1 HD where the sound was 5.1 channel AAC at about 320kb/s.

[Joe_90]

I've watched films on BBC1 HD where the sound was 5.1 channel AAC at about 320kb/s.

Freeview uses AAC for HD channels, Freesat uses AC3.

[Joe_90]

Check you have the latest build loaded on the boxes where PCM Multichannel is missing as it was only fixed recently. But anyway some boxes don't have that option in the drivers.

My AX61 does not have the PCM multichannel option, but my old GB Quad+ does. Most AV surround amps will not decode an AAC stream if passed through from the box, so you need a PCM option (or downmix) if you wish to listen such a setup.