Freeview hd 5.1 audio mp 1.3 (1 Viewer)

[PJM47]

Can anyone help with getting 5.1 sound on freeview hd with mediaportal 1.3. I have followed all the instructions for setting up mpar, lav codecs etc etc but it does not work when using toslink connection to the amp. I only get stereo. I have tried also using ffdshow and ac3 and setting up tv post processing. This works of sorts but ffdshow causes massive av sync problems and ac3 filter works only intermittently. MP looks like a great program but this is a real showstopper. Any help to get this working would be much appreciated. I know there are other similar threads but they are not quite appropriate to this issue.

 

[Owlsroost]

First of all, UK Freeview HD uses LATM HE-AAC audio encoding, which only LAV audio decoder and DivX AAC decoder filters can handle (AFAIK) (and you can't bitstream it directly to the amp either). Also the audio can change on-the-fly between programs - most are only in stereo, some in 5.1

I've not tried this, but one option is probably to use LAV audio, tick 'Enable Mixing', set the 'Output speaker configuration' to 5.1 and then use something like AC3 filter or FFDShow in post-processing (with just the 'raw' input formats enabled) to encode it to AC3. You also need to set the audio renderer in MP to one that can handle bitstreaming.

 

[PJM47]

Thanks for the reply. Using post processing with ffdshow as you describe does work in that I can get 5.1 sound working properly but the video and audio are now way out of sync. Video is 2 or 3 seconds after the audio! Which makes it unwatchable. Been playing for days with various settings but nothing seems to help. It seems like post processing is the only way to get he-AAC working but is there anyway to fix the severe sync problems this causes. Strangely with the additional audio processing, it is the video that is lagging behind not the audio.

 

[Owlsroost]

What are your system specs and which codecs are used for video, audio and post-processing ?

 

[PJM47]

Intel e8500 3ghz dual core. 4gb ram. Win7. Graphics/sound are onboard. Getting on a bit now but has been running windows media centre for years and plays anything hd without problems.

Can anyone confirm the post processing trick works for them? maybe I can the look at running it on a more powerful system. Also can anyone confirm freeview hd works with 5.1 sound if using hdmi as maybe I could update my amp instead. Ta.[DOUBLEPOST=1364499409][/DOUBLEPOST]Sorry forgot the codec question. Tried all sorts but mostly LAV for audio and video and ffdshow for post processing. tried Ac3filter for post processing but it was very unreliable.

 

[Owlsroost]

Yes, it should work fine as multichannel PCM on HDMI (I use a multi-channel analogue connection to my AV amp and that works OK).

In the meantime, you could try selecting 'Dolby Pro Logic II' in LAV audio mixing section (and possibly need to select 'stereo' for the speaker config). That should get you DPL II to the AV amp, which will get you some surround sound from 5.1 (better than stereo anyway).

CPU performance isn't the problem here - there is something weird going on with the post-processing (I suspect) - can you zip up and attach your logs ? (they are in 'C:\ProgramData\Team MediaPortal\MediaPortal\log')

 

[jameson_uk]

The issue is that TOSLINK (S/PDIF) can only carry a stereo signal or a DTS/DD bitstream.
The AAC on Freeview is 5.1 do you can not just output this directly.

If you want the 5.1 out you need to convert the 5.1 decoded AAC to DD or DTS. I used to do this with AC3Filter and this worked quite well. I am using HDMI now so just output multi-channel LPCM.

One option is to look at the MP Audio Renderer. Not 100% sure of the setup but there is an AC3 encoding option there which I believe will convert the 5.1 audio decoded by LAV to 5.1 DD and allow you to output this over S/PDIF

 

[PJM47]

Thanks for the info, makes sense. I,m using media portal audio renderer, I have tried the setting the AC3 encoding to 'forced' and 'auto' but it doesn't seem to do anything, I only ever get 2 ch PCM. Is there another setting somewhere I need? maybe in the LAV setup? Thanks.

 

[PJM47]

PS if I enable the LAV system tray and look at whats happening whilst playing video i get input aac_latm and output pcm 6ch displayed, so all looks good, it's just MPAR is not encoding to AC3.

 

[kiwijunglist]

In New Zealand Freeview the 2 channel audio is AAC and the 5.1 channel audio is AC3

Press F9 context menu when watching tv and first find out what the audio streams are.

If your audio is the same as NZ Freeview, you don't want any post processing, just set your audio codec to pass through AC3, then press F9 and choose the AC3 stream. You don't want to encode to AC3 either, you just want to use AC3 pass through. You don't want to use mixing either.

PS. For live TV you shouldn't use the MP audio render, you should use the default audio renderer, as you can't change the speed of live tv.

PPS. Make sure you press F9 and actually choose the 5.1 audio stream