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**popcornmix** · 2014-09-25, 21:41

(2014-09-25, 21:26)da-anda Wrote: Is DRC supposed to mean "dynamic range compression"? If so, please no abbreviations in descriptions in case this will be added to master.

DRC certainly means "dynamic range compression", although I'm not sure if fritsch is referring to xbmc's DRC (known as amplification), or a subsequent DRC (e.g. a receiver's night mode).

wrxtasy · (This post was last modified: 2014-09-26, 10:22 by wrxtasy.)

My head is still spinning trying to work it all out, just a simple answer please with out all the technicals ?

Question: With "Normalise levels on downmix" - Enabled.

Will I get sufficient centre channel boosting (Boost centre channel enabled) to hear dialogue clearly when down mixed 5.1 --> 2.0 ??

**fritsch** · (This post was last modified: 2014-09-26, 10:49 by fritsch.)

No. if you want it boosted, keep the normalize off - see the description given in the setting.

You can see "Normalize" as the inverse of "Boost Volume on Downmix".

I think we invert that setting, call it "Boost volume on Downmix again" ... to make it easier for endusers.

**fritsch** · (This post was last modified: 2014-09-26, 10:50 by fritsch.)

(2014-09-25, 21:41)popcornmix Wrote:
(2014-09-25, 21:26)da-anda Wrote: Is DRC supposed to mean "dynamic range compression"? If so, please no abbreviations in descriptions in case this will be added to master.

DRC certainly means "dynamic range compression", although I'm not sure if fritsch is referring to xbmc's DRC (known as amplification), or a subsequent DRC (e.g. a receiver's night mode).

I talked of our internal "Amplification" -> see how the "highest" value is used in the computation:https://github.com/xbmc/xbmc/blob/master/xbmc/cores/AudioEngine/Utils/AELimiter.cpp#L37

Fraludio · 2014-09-26, 11:42

Is there a raspbmc .img file (including this fix) available to flash to a SD Card?.

**popcornmix** · 2014-09-26, 12:09

(2014-09-26, 10:21)wrxtasy Wrote: Will I get sufficient centre channel boosting (Boost centre channel enabled) to hear dialogue clearly when down mixed 5.1 --> 2.0 ??

With or without normalise enabled you will get louder centre channel compared to the other channels.
If normalise is not enabled, the overall volume will be higher with the centre channel boost, and it may clip and distort.
If normalise is enabled, the overall volume should be the same with the centre channel boost, and it will not clip and distort.

I think normalise should be enabled if you want this setting to be "make background noises quieter compared to dialogue".

Note that "normalise" has the side effect of making downmixed (e.g. 5.1 audio output though stereo speakers) audio quieter than a similar file encoded as stereo.
It does protect you from distortion when the six channels are all loud at the same time and can mix together to produce a clipped signal.

wrxtasy · (This post was last modified: 2014-09-26, 12:49 by wrxtasy.)

(2014-09-26, 12:09)popcornmix Wrote: If normalise is enabled, the overall volume should be the same with the centre channel boost, and it will not clip and distort.

I think normalise should be enabled if you want this setting to be "make background noises quieter compared to dialogue".

(2014-09-26, 10:48)fritsch Wrote: No. if you want it boosted, keep the normalize off - see the description given in the setting

I think fritsch means Normalise off to keep volume the same as 5.1 source when downmixing i.e. all channels, but I was specifically asking about the centre channel only.

So Normalise enabled, Boost centre channel enabled as popcornmix said to quieten everything but the centre channel dialogue.

Thanks, this centre channel has been driving me mad with low volume for some time now on a 2.0 setup, this Boost centre channel option should be in other XBMC releases.

bobb0 · (This post was last modified: 2014-09-26, 14:37 by bobb0.)

edit: nevermind.

**zag** · (This post was last modified: 2014-09-26, 15:50 by zag.)

Just wanted to add to this I have also noticed the loud explosions and quiet speech, so much I have been using the remote to turn the volume up and down during an action movie. The recent Thor movie was almost unplayable.

Very interesting to hear others with the same issue, I assumed it was my receiver but don't remember having this problem with previous XBMC releases.

Will play around with the latest build tonight.

bobb0 · 2014-09-27, 06:11

Forgetting the technical aspects of this option, what is the end result in laymans terms? That should be the driving force in deciding what to name the option.

If the option leaves the centre channel at normal volume while reducing all other channels, I'd call it "Enhance dialogue on downmix"

Personally I think it would be best if any downmixing whatsoever occurred in such a way as to maintain Dolby Surround mixing so that a dolby surround processor could restore the surround mix. If an option exists to apply DRC to the downmix so that dialogue and background sounds are evened out, I'd call it that. "Apply dynamic range compression to downmix" -- but if that's not what this option does.. then the point is moot.

From an end user perspective.. if you're on a system that only outputs 2.0 audio, and XBMC is doing the downmixing... what is best for "me," the end user, to turn this option on or off? That should drive the phrasing. If turning it on enhances the sound to make it more palatable on a stereo-only system, ie, explosions quiet, dialogue loud then phrase it as "Apply dynamic range compression on downmix" If the opposite, "Maintain dynamic range on downmix" Anyone with reasonable intelligence should be able to figure it out and you can still use the description to explain it to the lowest common denominator.. (Ie, explosions loud, dialogue quiet or Explosions quiet, dialogue loud)

**fritsch** · 2014-09-27, 06:16

(2014-09-26, 15:50)zag Wrote: Just wanted to add to this I have also noticed the loud explosions and quiet speech, so much I have been using the remote to turn the volume up and down during an action movie. The recent Thor movie was almost unplayable.

Very interesting to hear others with the same issue, I assumed it was my receiver but don't remember having this problem with previous XBMC releases.

Will play around with the latest build tonight.

If you passthrough Audio to your AVR - we absolutely don't touch the signal (as you are talking of your AVR).

**fritsch** · 2014-09-27, 06:18

For the other naming conventions: I PRd a change to name that Option "Maintain original volume on downmix" which is the inverse of "Normalize levels on downmix" and enabled it by default.

We still need to talk about adding that Center Channel boosting option.

wrxtasy · 2014-09-27, 08:00

My two Bobs worth...

"Enhance Dialogue on down mix" or "Voice booster on downmix" would be my choice for the centre channel boosting option.

Apart from the increased speed of XBMC Helix this really is the best enhancement I have seen for the average user.

:-)

Fraludio · (This post was last modified: 2014-09-28, 15:34 by Fraludio.)

Yesterday I downloaded the last raspbmc build from miappa and toyed with the boost center channel. Boy what a difference, I was able to watch Maleficent without riding the volume control. Thank you, thank you very much for this.

**popcornmix** · 2014-09-28, 15:41

(2014-09-28, 15:33)Fraludio Wrote: Yesterday I downloaded the last raspbmc build from miappa and toyed with the boost center channel. Boy what a difference, I was able to watch Maleficent without riding the volume control. Thank you, thank you very much for this.

Out of interest what did you set the centre channel boost to?