Win Stereo Upmix in XBMC 13
#1
Hello guys,

hopefully this deserves a dedicated topic and is not something for the Beta testing topic.

How does the new feature from Gotham called "Stereo Upmix" work and what are the downsides compared to original multi-channel sound?
I'm asking because I own a Panasonic VTW60 and a Sonos Playbar. Unfortunately the TV won't passthrough surround via the optical out and the Playbar has to be connected via optical.

Currently I'm bypassing this via a Toslink splitter, but it's rather a dirty fix and also probably causing audio sync problems which I have.

Will I gain a quality boost by turning the feature on compared to normal stereo output if I play DTS or AC3 files? And to which format will the stereo be converted anyway?

Greets and thanks in advance for any help!
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#2
AFAIK it's the old "Output stereo to all speakers" setting.
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#3
Ah, I somehow thought it would be something from a new audio engine...
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#4
It will be upmixed to a 5.1 PCM stream if you are on hdmi. With the setting "Use AC3 Transcode" that 5.1 stream is ac3 encoded. The latter is the only option when ou are on spdif, as this only has 2 channels.

Best is if your AVR can output the 5.1 pcm stream directly.

And yes - everything that makes sound is done by Audio Engine.
First decide what functions / features you expect from a system. Then decide for the hardware. Don't waste your money on crap.
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#5
This is not exactly what it does. It would play stereo to all your configured speakers regardless if this is 4.0,5.1,7.1, or whatever > 2.0. All left hand side speakers get the same signal as FL, all right hand side speakers FR. LFE and FC get 0.5 of FL and FR.

EDIT: in case of "Use AC3 Transcode", this is 5.1
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#6
Yes, I know that direct surround would be best, but as I said, the VTW60 won't pass through surround, and a dedicated AVR is currently to big for my rack Wink

So I'm looking for the best & stablest solution.

So bottom line is, that the sound would be better (and hopefully "richer") with "Stereo Upmix" and "Use AC3 Transcode" turned on even if the TV will transform DD or DTS to Stereo?
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#7
No, if your TV doesn't passthrough multichannel sound it will make no difference if you enable stereo upmix or not, you will just waste CPU cycles.
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#8
i think i have a similar question/problem.
i just installed xbmc gotham (switched from mediaportal). and i just can´t figure out how to get 2ch stereo upmixed to 5.1 correctly.
i get the same sound from all speakers, which sounds just weird (used to use ffdshow with mportal to upmix stereo to 5.1, and that worked fine i.e dialogue was coming from the center only, etc.) .

i´m using xbmc on a zbox with ion with hdmi out to a sony str1040 avr.
XBMC audio settings:
output device: HDMI
channels: 5.1
config: optimized
stereo upmix: yes
normalize on downmix: yes
resample: medium
keep alive: 1min
gui sounds: when stopped
passthrough: yes
passthrough device: HDMI
AC3 capable receiver: yes
DTS capable: yes

that´s all the options i get listed in expert (can´t find "use ac3 transcode" for example).
help pls?
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#9
Did you not see Post #5.

Stereo Upmix takes FL & FR and produces 5.1 as follows:

FL = FL
FC = 0.5xFL + 0.5xFR
FR = FR
RL = FL
RR = FR
LFE = 0.5xFL + 0.5xFR

So you won't get dialogue from the center only.
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#10
oh ok, didn´t quite get that in post #5. that´s not what i was hoping for, but thanks a lot for the info.
and how can i set options like "use AC3 transcode" to display? or is there any way to get it to sound less like all speakers put out the same audio?
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#11
What you want is not possible in XBMC.

The transcode option is only available when Number of channels is set to 2.0 as is designed to send 5.1 AC3 over connections that don't support 5.1 PCM such as SPDIF.
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#12
No way to deactivate the center output ?
And what happen to SL and SR??
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#13
On kodi for me. I have the 16.1 release. Which works great btw. Quicker loading times, especially with the tv menu option. The stereo upmix has always been in kodi's original setting for me. When watching a movie, I click on the sound option and it's in there. It seems to be leveling out the sound so far. Well. I have the bass turned up, and that on. Seems to be helping with the low talking volume in movies atm. But this is the first movie I have tested it with.
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#14
(2014-05-15, 21:06)jjd-uk Wrote: Did you not see Post #5.

Stereo Upmix takes FL & FR and produces 5.1 as follows:

FL = FL
FC = 0.5xFL + 0.5xFR
FR = FR
RL = FL
RR = FR
LFE = 0.5xFL + 0.5xFR

So you won't get dialogue from the center only.
is it possible (yes) to do it more like Pro Logic I ? Its not good to only copy FL to RL. Front is Front and Back is for Ambient. The perfect solution was the win10 "Speaker Fill" Setting but this wont work anymore with nVIDIA HDMI
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#15
It's meant primarily for music and is meant to function like the "All speaker" function some AVR have. How are we supposed to produce a Pro-logic style output from a normal stereo source? it needs to be done at the audio encoding stage where the Pro-Logic matrix can be embedded, so any untouched stereo movie from the last 40 should be able to take advantage of Pro-Logic decode on the AVR.
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