Dolby pro logic II and other dolby conversions greyed out on amp when fed from pc

[413x]

now this definitely was available before on a different machine with the same gpu

I am feeding an av receiver from a 1.4a hdmi gpu with a 1.4a hdmi cable to a 1.4a amp. I watch tv via the pc etc through a 5.1 system and like dolby pro logic 2 for the non 5.1 channels. For some reason i cannot select the DSP for dolby in any of its creations, nor neo 6 cinema, parameters that are available are
5.1 enhanced, 5.1 stereo, 2.0 stereo, straight, and the useless 'scenes' like hall in Munich

Anyone know why this is? i am stuck!


amp is yamaha and gpu is 6950 amd

 

[lucid]

There's a good chance that the sound coming from the gpu is being encoded in some way that stops the amp doing its job.

If the amp receives a raw bitstream signal then all the options for that signal become available. e.g. bitstream from a Blu-ray player means that DTS-HD, Dolby TrueHD, DTS and DD are available if the disc has those audio tracks. If the player is set to PCM output then the amp is getting 6 channel PCM that is already decoded by the player, but often not to the same quality.

Check your software settings on the PC. Make sure that bitstream is selected

 

[413x]

Think I'm going to have to reinstall windows, i cannot stop it forcing either 2.0 or 5.1 in speaker setup

It will not bitstream, grr this is driving me crazy. Has taken a lot of hours to get this far

 

[Alfie]

Pro Logic and other DSP modes work only for PCM audio signals with sampling frequencies of 32KHz, 44KHz or 48KHz

If your stereo sources can't use Pro Logic it's likely because you've upped the sampling frequency to 96khz or higher.

Hope this helps

 

[413x]

Well this is what I have

Passthrough is set everywhere I can find with enhancements off

In the speaker setup section this is what happens
If I set 2.0 I can get the amp to select dolby etc but I get no 5.1 sound from 5.1 sources
If I set 5.1 I get 5.1 from blu ray, 2.0 from mce tv footage but cannot select dolby on the amp.

Why can't I disable the speaker setup?

 

[413x]

Pro Logic and other DSP modes work only for PCM audio signals with sampling frequencies of 32KHz, 44KHz or 48KHz

If your stereo sources can't use Pro Logic it's likely because you've upped the sampling frequency to 96khz or higher.

Hope this helps

Will check but fairly sure it's 44

 

[james.miller]

Pro Logic and other DSP modes work only for PCM audio signals with sampling frequencies of 32KHz, 44KHz or 48KHz

If your stereo sources can't use Pro Logic it's likely because you've upped the sampling frequency to 96khz or higher.

Hope this helps

This i'm sure will be the reason however I dont think the codecs themselves have any upper limits, although the DSP processors in av amplifiers that apply them DO have limitations. My onkyo is quite happy using just about every DSP algorithm it has available at 96khz, but everything gets disables at 192khz, including audyssey room correction.

So yes, it's like that the sampling rate is set too high for the avamp to apply those surround modes.

 

[413x]

Have tried it at 44 and 48 still no joy

It appears that the pc is showing the amp 5 channels of audio even when playing stereo sources, the amp thinks it is getting 5 channels so dolby processing isn't available.

Also if I set sound to 2.0 in sounds > configure I can get dolby working but it forces 5.1 off blu rays down 2 channels

It's either 2 or 6 channels, it doesn't appear to be dynamic

 

[james.miller]

ok i understand now.

It's either 2 or 6 channels, it doesn't appear to be dynamic

yeah it wont be. However this shouldnt be a problem if we can work out what bitstreaming isnt working.
What software are you using to play your blurays and what version of windows are you running ?

 

[413x]

ok i understand now.

yeah it wont be. However this shouldnt be a problem if we can work out what bitstreaming isnt working.
What software are you using to play your blurays and what version of windows are you running ?

Yes only just figured what was wrong. Least half way there

Using windows 7 pro 64
Playing blu rays through media center with media browser pluggin
Using shark007 codec pack

 

[413x]

Found the solution.

Had to enable 2.0 in windows control panel
Set bitstream in the x64 shark codec pack

And this ia what i probably didnt do..i thought i tried every comb
Enable LAV splitter in the miscellaneous section of the codec pack

Now tv in stereo is converted to dolby pro logic ii by the amp
Music can be converted into 5.1 but correctlt defaults to 2.0
Mkv blu ray rips with hd audio are picked up as 5.1 by the amp and bitstream is confirmed working as the pc cannot control volume, only the amp

Drive C imaged!
Think i am a partial expert now!