[ABM-DVB-T/T2] French TNT - No sound unless I flip channels - also low volume for pcm

[JerryK132]

Hello
I'm a newcomer to Enigma2 and Vix. I've set up my Vu+4K-SE and Denon AVR2700H Receiver and Sony Bravia as best I can and I have a number of difficulties. For clarity I'll keep them separate. I have read large parts of the relevant manuals and being pretty technical I've managed to figure a lot out even when the manual is different or silent. So I've tried to do my homework before bombarding anyone with silly Qs! So that's the context.

My aim in purchasing the STB is to have a unified system combining FreeSat and French TNT, preferably in one list. I have tuned the box to FreeSat and TNT using the two physical tuners installed. I'm near France and get my service xmitted from Rennes. My dish is fitted with a hybrid LNB and I am using two universal feeds as WB is not supported by the tuner. I frequently update all parts of the system software so I think I am up to date.

If I run UpdateProviders I get an err 404 for F Terrestrial (created by ABM, I think). This may be a clue.

I have two All Channels bouquets, one for FSat and TNT. I can select FSat channels but if I select a TNT channel i often get no sound. The sound is shown as PCM or PCM zero or MPEG. Sometimes selecting Ch+ gives me the next channel with sound. Then, usually, Ch- gives me the desired channel with sound. If there is still no sound I restart the GUI and the sound miraculously appears on the desired channel.

A potentially related sound problem is that if the sound is not AC3(+) or AAC - ie it's pcm or mpeg, the sound levels are very low indeed forcing me to turn the volume up very high. Both the AC3/AAC downmix settings are set to Passthrough. Any way this can be fixed to avoid low-flying speaker cones when the audio stream (or channel) changes?

Thanks for any help.

 

[twol]

Hello
I'm a newcomer to Enigma2 and Vix. I've set up my Vu+4K-SE and Denon AVR2700H Receiver and Sony Bravia as best I can and I have a number of difficulties. For clarity I'll keep them separate. I have read large parts of the relevant manuals and being pretty technical I've managed to figure a lot out even when the manual is different or silent. So I've tried to do my homework before bombarding anyone with silly Qs! So that's the context.

My aim in purchasing the STB is to have a unified system combining FreeSat and French TNT, preferably in one list. I have tuned the box to FreeSat and TNT using the two physical tuners installed. I'm near France and get my service xmitted from Rennes. My dish is fitted with a hybrid LNB and I am using two universal feeds as WB is not supported by the tuner. I frequently update all parts of the system software so I think I am up to date.

If I run UpdateProviders I get an err 404 for F Terrestrial (created by ABM, I think). This may be a clue.

I have two All Channels bouquets, one for FSat and TNT. I can select FSat channels but if I select a TNT channel i often get no sound. The sound is shown as PCM or PCM zero or MPEG. Sometimes selecting Ch+ gives me the next channel with sound. Then, usually, Ch- gives me the desired channel with sound. If there is still no sound I restart the GUI and the sound miraculously appears on the desired channel.

A potentially related sound problem is that if the sound is not AC3(+) or AAC - ie it's pcm or mpeg, the sound levels are very low indeed forcing me to turn the volume up very high. Both the AC3/AAC downmix settings are set to Passthrough. Any way this can be fixed to avoid low-flying speaker cones when the audio stream (or channel) changes?

Thanks for any help.

what happens if you chang passthrough to downmix?

 

[Joe_90]

Most AVRs will not decode AAC, so if your TNT channels are using AAC, then you will have to downmix them as @twol has suggested. AC3 or any of the Dolby/DTS variants are usually handled by AVRs and decoded internally, but not AAC.

As regards the fixed volume on passthrough codecs like AC3, what I do is set the box volume (the VU+) high so that non-Dolby channels are at a similar level to the passthrough channels. Then, you don't get huge variations when you switch.

 

[JerryK132]

Thanks Twol and Joe_90

If I set AC3 to Downmix the levels are roughly equalised - I have to raise the volume to 90% to hear AC3 as well! That reduces/removes the difference, but is a very low actual output. Also presumably I lose the Doilby etc data.

According to the docs my AVR supports MPEG-4-AAC as well. I assume that is the same as AAC.

The way I have set upo my TV/AVR/Vu+ causes the various volumes on the remotes all operate in tandem. The upside is that I need slightly fewer remotes to do anything! All those HDMI settings which are hard for me to get my head around. But you are suggesting that despite the passthrough settings, unlinking the vu+ volume from this might give comparable outputs for all the different signal formats, I think?

I'd tried to unlink the remotes volume controls by changing various HDMI settings without success. Then I understood that the VU+ front panel vol buttons are not linked to the AVR vol. In fact remotes are linked independently. So as Joe_90 said, the front panel can be used to set the box volume to match the passthrough volume which is independent of it. So that problem bites the dust.

Thanks both for your help.

 

[Joe_90]

I did a quick search on the X2700H and found this for bitstream format:


Dolby Digital / DTS / Dolby Atmos / Dolby TrueHD / Dolby Digital Plus / DTS:X / DTS-HD Master Audio / DTS-HD High Resolution Audio / DTS Express

This would be similar to my Sony AVR and my previous Onko. AAC is rarely supported on the HDMI bitstream. Usually you have to convert to LPCM between 32kHz and 192kHz.


EDIT - I did a bit of further digging. The USB and network interfaces will support AAC "The Denon AVR-X2700H supports the following audio formats, sampling frequencies, and bit rates via its wired network connection." My Sony is similar on the USB interface, but not on the HDMI interface which is how your sat/terrestrial receiver is interfacing, so we are both right. On the sat box you will have to downmix AAC to PCM .

 

[JerryK132]

Hi Joe_90. Just spotted your now ancient reply. Apologies for not seeing it earlier!

I now use an optical link between the enigma and the Denon AV. Everything is on passthrough. That seems to work well.

Thanks - and apologies again!

 

[JerryK132]

what happens if you chang passthrough to downmix?

Thanks. Apologies for not responding. Sound worked if I downmix them. But I wanted my receiver to do the decoding as I believe it has a higher spec... I eventually tried optical which seems to have solved the problem. The "no-sound" problem eventually just disappeared on its own. No idea why!
Thanks again.

 

[Joe_90]

I suspect that you are not actually using "passthrough" as that happens on HDMI. The optical out probably downmixes by default, so your received AAC stream is being downmixed to PCM.

 

[JerryK132]

I suspect that you are not actually using "passthrough" as that happens on HDMI. The optical out probably downmixes by default, so your received AAC stream is being downmixed to PCM.

Interesting, Thanks. I did read that SPDIF has some restrictions I did not expect. or know about.. I'll do some comparisons at some point again...

 

[Joe_90]

S/PDIF can handle two channel PCM at 192kHz max (more usually 96kHz depending on exact hardware). Otherwise, if you need multichannel audio, then you are limited to Dolby AC3 / DTS compressed streams. The interface won't handle high-definition multichannel audio, only stereo. It doesn't matter whether you use optical or coax. It's great for conventional CD stereo audio or high-def stereo, but it won't handle the likes of DTS Master Audio or any of the high bitrate Dolby variants that you get with 4k Blu-ray for example.

 

[JerryK132]

S/PDIF can handle two channel PCM at 192kHz max (more usually 96kHz depending on exact hardware). Otherwise, if you need multichannel audio, then you are limited to Dolby AC3 / DTS compressed streams. The interface won't handle high-definition multichannel audio, only stereo. It doesn't matter whether you use optical or coax. It's great for conventional CD stereo audio or high-def stereo, but it won't handle the likes of DTS Master Audio or any of the high bitrate Dolby variants that you get with 4k Blu-ray for example.

I remember now - yes, it was the more complex surround info that is allegedly restricted on S/PDIF. I've not really had a chance to fully test things - no decent sources, no Blu-Ray, etc. I do have a (Vix) setting in setup/audio video named 3D Surround, which was set to HDMI and which I have just changed to SPDIF (Also PCM MultiChannel= Yes). I'm a bit out of my depth here as there are so many settings and two boxes and I'm relying on broadcast sources, that it is hard to analyse logically - even given that I'm qualified (or was!) to do so. Every so often the planets seem to align (along with a recent film source!) and the surround sound jumps out at me...

In an ideal world the fact that I chose 4K+ compliant devices would result in the boxes agreeing amongst themselves what settings to use - even dynamically - and I could just enjoy the result.

But are you saying that downmixing just the AAC would actually be a better option, given my setup?

Is there a document which covers the combination of vix and VU+ - as the help/description texts in the UI are sometimes a bit brief....?

 

[Joe_90]

Usually on most sat/terrestrial boxes there is an option of transcoding AAC into AC3 which will work on S/PDIF and give you surround sound if the broadcaster actually carries it. My exposure to AAC is limited in that my terrestrial TV source here in Ireland does not use surround codecs at all - just MPEG stereo. On satellite from Astra (Sky FTA and Freesat) I only get Dolby AC3 suuround from BBC and CH4. ITV only ever transmit stereo sound tracks and I don't have a Sky subscription. My Sony AVR will handle all the high-def surround codecs like DTS-MA and Dolby True-HD and Atmos etc., but not native AAC.

 

[JerryK132]

Usually on most sat/terrestrial boxes there is an option of transcoding AAC into AC3 which will work on S/PDIF and give you surround sound if the broadcaster actually carries it. My exposure to AAC is limited in that my terrestrial TV source here in Ireland does not use surround codecs at all - just MPEG stereo. On satellite from Astra (Sky FTA and Freesat) I only get Dolby AC3 suuround from BBC and CH4. ITV only ever transmit stereo sound tracks and I don't have a Sky subscription. My Sony AVR will handle all the high-def surround codecs like DTS-MA and Dolby True-HD and Atmos etc., but not native AAC.

Thanks again. I'm much clearer now. It's a bit academic, I suppose, as the AAC sources are rare for us both. I will look out for an AAC source to test. My Denon reports what it is receiving, so it should be easy with the right source.