dvb w/ AAC 5.1 --> AC3 5.1 - guide. (1 Viewer)

[gibman]

If you want to have dolby digital 5.1 output over spdif from a dvb channel with a "he aac 5.1" audio source, then this is the guide for you.

In denmark we have DR1 HD (720p h264), which currently contains 2 he aac audio tracks.

1) aac 2.0
2) aac 5.1

Changing to track #2 emits no sound on most of the aac codecs Ive tried. Some emits noise and crashes MP.

As my amp has DD 5.1 decoding capabilities only and therefore does not understand a straight aac signal.
We have to encode aac 5.1 track to to AC3 (dolby digital or DTS) 5.1 in realtime.

We can do this by adding ffdaudio decoder as a postprocessing filter (ac3filter probably works just as good).

also, download divx plus from:
DivX Plus Software ? Thank you for downloading | DivX.com

install only the codec part.

also download and install ffdshow.

In MP config. do the following:

1) under TV codecs - aac audio decoder: divx aac decoder
2) under TV-TV post processing - add ffdshow audio decoder (place a checkmark).
click on filter properties on ffdshow audio decoder.

under ffdshow properties do this:

under codecs:
aac: disabled
uncompressed: all supported.

under output:
ac3 (spdif encode mode) : checked
encode only 5.1ch streams: checked
bitrate: 640

Now fire up MP and verify that the audio registers itself as an ac3 stream on your amplifier.

the preferac3 setting is sadly not working when dealing with ac3.
Currently you will have to manually choose the audio track each time within the fullscreen TV context menu (F9).

Both audio tracks are listed as:

1 dan:LATMAAC
2 dan:LATMAAC

as you can tell preferac3 code will never find out what track to choose.

maybe the setting should be renamed to prefer multichannel

A shame we only provide the audio type, and not how many channels.

/gibman

 

[daffydk]

Did you figure out how to rename the latmaac so it automatic can choose between the audio stream ???


And THANX alot gilbert it worked like it should ...

 

[Kiwi]

Hi

Ive got a setup very similar to provide AC3 to my amplifier using ffdshow as post processing in TV. All works well, however there are two downsides
1 fast foward is broken (doesn't work)
2 mute is broken (ie doesn't mute)

Does anyone else have the same problem?
Thanks

 

[kiwijunglist]

Kiwi - I don't have this problem, I can FFWD and mute fine. I use the default aac codec, and use ms dmo for the ac3 audio in the tv section. I have Win7, SAF 5.0 beta installed and use spdif. ts reader can't directly connect to ffdshow audio, and since ms dmo can handle ac3, there is no need for ffdshow post processing in the tv section for NZ users. The guide above is for HDTV 5.1 AAC, in NZ we have 2.0 AAC / 5.1 AC3, so the instructions are not intended for you.

 

[m0t0k0]

I know the post is pretty old now but it seems to be the only information on this on MediaPortal

I have recently setup a DVB-T2 tuner which is as far as I know providing AAC audio this is sent via HDMI to my amp TX-SR605 which is outputting stereo sound

What I would like to do is postprocess this into AC3 to give me 5.1 DD on my amp

Is that correct/best way to do this to use FFDshow to transcode on the fly and pass through the AC3?

Cheers Jake

 

[hoborg]

m0t0k0:
1)Install SAF6 - enable audio passthrough durning installation
2)add FFDshow audio processor to MePo postprocessing
Done

 

[m0t0k0]

Thanks for the reply I'm currently using LAV and pretty happy with how it is working so far. Will install a stand alone copy of FFDshow and try to configure it myself (I have a pretty good idea how to achieve what I want) Its good to know I'm on the right track.

 

[Owlsroost]

The Freeview HD (UK) is a mixture of 2.0 and 5.1 AAC (as far as I know) - with an HDMI connection to the AV amp I would expect you would get 2 or 6 channel PCM at the amp (depending on the Windows speaker settings).

Tony

 

[m0t0k0]

Thanks for the help! I had some degree of success last night.
I setup acording to the guide in post one but instead of Divx codec I used LAV for the AAC and then passed this to ffdshow to convert to AC3

Which did give me AC3 at my amp and is shown that ffdshow is used here

The problem I found was that if I switch to an SD channel I lose the ffdshow filter and switch back to HD is remains missing so no AC3

I found that I could reliably get SD channels to have AC3 like this

and this would be persistent on return from a HD channel
I just cant get AC3 for HD channels to work reliably

The Freeview HD (UK) is a mixture of 2.0 and 5.1 AAC (as far as I know) - with an HDMI connection to the AV amp I would expect you would get 2 or 6 channel PCM at the amp (depending on the Windows speaker settings).

Tony

I see from pressing F9 I can select the audio channel language. This if I'm correct point to a stereo and multi channel audio streams.
My system selects the first (stereo channel) and if I try to select the second the sound goes crazy

I meant to include logs but I forgot to upload them to dropbox but will add them tonight.

So any ideas
(system specks on the left)

Another question why cant I just select ffdshow as my ACC decoder and have it output AC3? Why do I have to pass through the LAV audio decoder first?
In MediaPortal TV codecs under ACC the only option are MONOGRAM and LAV why cant I just put ffshow in there?

 

[m0t0k0]

Anyone able to help me on this

I tried last night with SAF 6 but had exactly the same problems as before. Initialy tuning to a channel and I get AC3 but if I change channel ffdshow filter drops out of the graph and I only get LPCM.

Any way I can get MP to force ffdshow?