Freeview HD - UK - DVBT2 and Decoding HE-AAC to Dolby Digital / DTS

[Dodgexander]

I am trying to make sure that using Next PVR with my PCTV Nanostick 290e T2 that I am correctly receiving 5.1 HE-AAC and decoding it into Dolby Digital (or DTS) for my AMP to process the signal.

At the moment I have Next PVR set up to use the latest Lav Audio decoder for HE-AAC. Sound works, but there is no definitive way for me to see if I am in fact receiving 6ch audio that is then being converted to Dolby Digital by my sound card. For instance, I do not know if I am only receiving 2ch audio which is then being mixed to 5.1 by my sound card.

A couple of questions really, I have tried using graphedit, but cannot connect to the Next PVR graph for live tv, I have tried to open the Lav Audio config, only to find no "pin" tab. How can i make sure everything is being done correctly?

Second question, is there a way to use a filter like FFDSHOW to post process only HE-AAC 5.1 to Dolby Digital so that when the audio switches between 5.1 and 2 channel it switches between stereo and dolby digital on my amp?

Obviously I am testing this using the HDTV channels in the UK whilst they are broadcasting 5.1 sound and I am using the hardware of my Xonar HDAV to convert to Dolby or DTS.

Many Thanks for any help!

[imilne]

You could try ac3filter as it gives you info on what it's decoding. I know it does AAC but not sure about HE-AAC. I'd be interested to know regardless. Another option is to download MediaInfo and point it at a recording...it'll tell you what audio it contains.

Oh, and if you (can) use ac3filter then let it do the encoding to DD, that'll sort your stereo/5.1 issues too, as it'll encode stereo to DD 2.0 which means your amp can apply pro logic on it. With 5.1 (AAC) it'll then output 5.1 (DD).

Iain

[Lao Pan]

If you go to the lav audio config while playing audio there will be an output tab with a level indicator for each channel.

I have used the nano-stick for over 2 years with lav audio and the Realtek HD on-board sound outputting DTS 5.1 to my Amp over toslink optical It works - really well - just ask the neighbours

Things to remember with Freeview HD Audio - ITV1 HD is only stereo, BBC & 4 HD broadcast in 5.1 & stereo and sometimes in 5.1 with 3 silent channels which is most annoying,

Can the ac3filter decode HE-AAC now? Before it was only DivX and Lav that could do it.

[imilne]

Things to remember with Freeview HD Audio - ITV1 HD is only stereo, BBC & 4 HD broadcast in 5.1 & stereo and sometimes in 5.1 with 3 silent channels which is most annoying,

I don't know how it is on Freeview, but on Freesat (which uses Dolby Digital rather than HE-AAC) all the stereo transmissions are actually DD 2.0. This means you can bitstream everything to an amp and have it either treat 2.0 as Pro Logic or leave it alone for 5.1 stuff. For the other channels, which use mp2 audio, then I have ac3filter encode to DD before bitstreaming.

Can the ac3filter decode HE-AAC now? Before it was only DivX and Lav that could do it.

I've since grabbed a couple of Freeview HD test recordings I found online and unfortunately the answer is no. ac3filter doesn't even show up in NPVR's list of possible HD-AAC decoders either.

Iain

[Dodgexander]

If you go to the lav audio config while playing audio there will be an output tab with a level indicator for each channel.

For all the trying, when playing Live TV in NPVR and opening Lav Audio properties I do not see the usual output tab I do when playing back a file, nor do I see the pin info in any codecs for that matter, including lav video. For lav video it just states "innactive".

I've since grabbed a couple of Freeview HD test recordings I found online and unfortunately the answer is no. ac3filter doesn't even show up in NPVR's list of possible HD-AAC decoders either.
Iain

Sorry I took a while to reply, i changed my email address and wasn't receiving the confirmation.

Overall I find it dificult to actually know what NPVR is using for playback, you can't connect it to graphedit and it seems like its not using the filters specified.

I read somewhere that for live playback, NPVR just uses the direct show priority filters, but if that is the case, even with the windows filters disabled on my system, NPV is still not using Lav.

[imilne]

The log file will tell you what decoders are in use, but for Live TV and recordings I think it will only use what you set in the decoders screen. For anything else played via the Videos library then it's up to DirectShow to pick.

Iain

[Dodgexander]

I have attached my log, but I am not to sure where I am going wrong...but there are multiple lav entries listed, not sure how i can get rid of them.. It should be using Lav video and audio as selected in options. But it appears not to be.

Thanks for helping.

[Dodgexander]

I am trying to figure out also why lav video is inactive when playing non-sd mpeg channels. its set to my decoder in options.

[mvallevand]

In the UK samples I've seen there are often multiple audio stream types. Do you have lav set for all of them?

Martin

[Dodgexander]

Yes its set, I since uninstalled all codecs and players and installed SAF. Saf has a graph that lets you see whats playing, not sure how it enables it, but it does.

The problem is the filters are working, but the config isnt. For instance. When I open lav video config or audio config during, they do not show any details like they do elsewhere when playing a file. This means I can't play around with different settings and compare, which is a bit annoying, because i was going to set LAV to be my video decoder for mpeg2 only with yadif enabled. But this way i also have to keep yadif enabled when playing back recordings in media player classic with hd files and my pc cannot cope with 1080i.

Its also annoying, because I was hoping to set FFDSHOW as a post processing filter to turn only he-acc 5.1 into AC3, but turning it off unless the source is 5.1.

This way i have to manually change the setting each time the audio changes.