5.1 track AAC surround sound audio with Freeview receivers

[Mickkie]

Unfortunately I think the issue lies with your Sony equipment.

I can confirm there is nothing wrong with the Sony TV, (which outputs AC3), or the Yamaha AVR. The Yamaha A/V department kindly responded to my enquiry and pointed me to standardised audio streams for testing AAC-LC (Fraunhofer Research). I uploaded these streams to the Mut@ant and also to a PC, both of which I connected to the AVR via HDMI. I confirmed the AVR is capable of processing decoded PCM 5.1 surround sound as provided to it by the PC. The Mut@ant however will only provide a (partially) downmixed PCM stereo stream. The Surround Left and Surround Right channels are fed to (mixed in with) the Front Left and Front Right speakers respectively. The Front Centre channel is fed out of both FR/FL speakers. From what I can detect however, the LFE channel remains silent - I couldn't hear a low base sound coming out of the subwoofer.

Would anyone know why the Mut@nt won't decode 5.1 ch AAC-LC into a multichannel PCM and feed this to the AVR? Is this an OpenVix, Enigma2, or Mut@nt's hardware capability issue?

 

[Joe_90]

@Mickkie - I'm not sure why the Mutant will not pass 5.1 AAC as 5.1 PCM but the downmixing seems correct to me. The rear channels are fed to the corresponding front ones. The centre channel is fed to the two front ones. The .1 channel is LFE and has no part to play in a 2.0 system. You may need to try to borrow a MIPS player (like a Gigablue Quad Plus) which can convert AAC 5.1 to AC3.

 

[dntaylor]

I Have just bought a Gigablue UHD Quad 4k with an optional Freeview tuner from WOS (love this receiver) but I can't get the AAC transcoder to work in Openvix after selecting it.

I have it connected optically to my amplifier but when I select transcode AAC to AC3 no sound comes out of the amplifier but it does from the television.
My LG OLED TV is also connected optically and this does transcode AAC to AC3 as my amplifier is displaying Dolby Digital 5.1 when watching a Freeview HD broadcast from the TV tuner.

Even though sound comes from the TV watching it through the receiver and not from the amplifier it is not transcodeing, because the TV dose pass-through Dolby Digital and my amplifier would be showing this. I was thinking it was just going through the HDMI and not through the optical but this is not the case. Can anybody shine any light on this and has anybody manage to get it to work?

Many thanks