Realtime digital multichannel downmix solution

Posted by: Macniek on 23 July 2015

Hi all, 

This is my first post here. Im a lucky owner of a mu-so. Besides streaming I also use it as a soundbar for TV. With a optical switch I managed to connect the decoder as well as a mac-mini from where I watch movies and series through the optical input. 

 

If read the artical posted by Phil Harris https://forums.naimaudio.com/to...-a-tv-or-set-top-box regarding the low volume and pcm imput requirements. 

I was aware of this fact when choosing for the mu-so but i must say, it do get frustrated sometimes when i watch a movie in Kodi because it downmixes the DTS or other multichannel format to 2 channel stereo / pcm. 

 

This made me wonder: isn't there a hardware / software solution available that does this better? Probable my "How to google someting" knowlegde is outdated but I can't really find something that would to the job. 

 

I know: look for movies / series that have a proper PCM audio channel but from my point of view: these become less and less available. 

 

Does anybody here ever tried to find a way to improve the default downmix capabilities running os x software or is there a optical multichannel in > pcm out hardware solution anybody can recommend?

 

Interesting to find out if there are more people looking for a solution regarding this issue.


Kind regards,

Niek

 

 

Posted on: 23 July 2015 by feeling_zen

Not 100% sure I understand your question.

 

I don't believe low volume levels are a problem across the board for all TVs. Can't you just hook all your video sources to the TV and then in the TV under it's audio options, select LPCM with external volume as the output? Most modern sets allow you to select a number of output and downmixing and transcoding options.

 

I take the optical from my Bravia and even though it runs to an AV receiver I select LPCM stereo as the output (mainly because the surround mixing on commercials and regular TV shows is so dodgy).

 

 

Posted on: 25 July 2015 by Macniek
Originally Posted by feeling_zen:

Not 100% sure I understand your question.

 

I don't believe low volume levels are a problem across the board for all TVs. Can't you just hook all your video sources to the TV and then in the TV under it's audio options, select LPCM with external volume as the output? Most modern sets allow you to select a number of output and downmixing and transcoding options.

 

I take the optical from my Bravia and even though it runs to an AV receiver I select LPCM stereo as the output (mainly because the surround mixing on commercials and regular TV shows is so dodgy).

 

 

Hi Zen, 

 

My Pioneer plasma does not support ARC sadly. You did send me on track by looking in a receiver with optical-out. Sadly that option is not mainstream and only on the high end. 

 

I looked at something like this: http://www.octavainc.com/HDMI%...0ARC%20port_pro.html but i don't know yet if i can control the settings of the output.

 

Cheers

Posted on: 25 July 2015 by Simon-in-Suffolk

Niek, I don't know what digital source your are using but many DVB satellite muxes carry a two channel MPG2 audio feed as well as the multichannel feed, and so downmixing is not actually undertaken by the STB. There are various speciliast sites on the web that can show the parts of the mux for a particular channel.

Of course there is no gaurentee that the level of the transmitted 2 channel MPG2 signal is the same as the multichannel feed. I have no level problems with my digital 2 channel feed from Sky STB.

Simon

Posted on: 25 July 2015 by Simon-in-Suffolk

Further I would not recommend not taking a multichannel AC3 feed and down mixing to a MP2 feed - you would be transcoding from one lossy format to another lossy format and the SQ will take a dive..

Looking at most of the UK satellite channel muxes, they contain 48kHz MP2 stereo audioPID and some contain additional multichannel AC3 audio as an additional audioPID.

Simon