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Old 7th August 2011, 19:43   #361  |  Link
manolito
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Quote:
If with "default sox downmix algorithm" you mean the "channels" filter (or "-c" option), then it does not work very well!
No, I was talking about this:
Quote:
By default, where an output channel is mixed from multiple (n) input channels, each input channel
will be scaled by a factor of /n. Custom mixing volumes can be set by following a given input
channel or range of input channels with a vol-spec (volume specification).
Normally I would assume that the rear channels should be mixed into the stereo file at a lower volume than the front channels. But as I said, the result sounds pretty good to me even without specifying the volume (letting sox use an even scaling factor for each channel).


BTW I cannot download the latest build from SourceForge ATM. Something is wrong with the links, it sends me into a loop.


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Old 7th August 2011, 21:31   #362  |  Link
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Quote:
Originally Posted by manolito View Post
Normally I would assume that the rear channels should be mixed into the stereo file at a lower volume than the front channels. But as I said, the result sounds pretty good to me even without specifying the volume (letting sox use an even scaling factor for each channel).
You are right. Giving the same weight to all channels probably isn't the optimal choice. Mixing the "center" input channel into the "left" and "right" output channels with the same weight as the the "right" or "left" input channels gives a bias towards "center". More correct would be 2/3 left + 1/3 center for the left channel and 2/3 right + 1/3 center for the right channel, I think. We can give that a try. Still the question is how much weight the back/side channels should get, compared to main (left/right) and center. I am open for suggestions here...

Quote:
BTW I cannot download the latest build from SourceForge ATM. Something is wrong with the links, it sends me into a loop.
I can confirm. Looks like a problem at SourceForge.net. The file was uploaded hours ago, but is only available from one single mirror ("Waix") at this time.

And even that mirror doesn't seems to work, it just redirects to the "Files" page. Anyway, you can use Auto-Update for now...
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Last edited by LoRd_MuldeR; 7th August 2011 at 21:35.
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Old 7th August 2011, 22:38   #363  |  Link
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Quote:
Anyway, you can use Auto-Update for now...
Thanks...


Luckily the correct values for different downmix scenarios have already been established... Tebasuna and Selur seem to be the guys to talk to.

Here is a link to a corresponding thread:
http://forum.doom9.org/showthread.ph...94#post1362794

For stereo downmix this post is the one to look at:
http://forum.doom9.org/showthread.ph...96#post1363496


Hope this helps...

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Old 8th August 2011, 00:02   #364  |  Link
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I can't really follow these posts, but I tweaked the channels weights for the downmix filter some more:
https://github.com/lordmulder/LameXP...er_Downmix.cpp

Basic idea: If we first create a Stereo downmix and later downmix further to Mono from there, then Center and LFE should have the same volume as Left/Right in the final mix. This means that the Center and LFE channels have to be reduced to 50% (compared to the Left/Right main channels) in the Stereo mix, because Center and LFE are mixed into both, the Left and the Right output channels. So the reduction to 50% will avoid the bias towards Center/LFE in the downmix. Moreover the Back (Surround) channels will also be reduced compared to the main channels. Sample attached.
Attached Files
File Type: zip multichannel_downmix.zip (103.8 KB, 15 views)
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Old 8th August 2011, 00:31   #365  |  Link
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According to Selur's post the sox remix values for stereo downmix of a 6ch source should be:

1v0.3694+3v0.2612+4v0.3694 2v0.3694+3v0.2612+5v0.3694

Note that only channels 1,3,4 are used for the left channel, 2,3,5 for the right channel.

Your channel assignment for a 6ch source is 1,3,4,5 and 2,3,4,6 which is somewhat different...


Anyways, your stereo mix sounds pretty good.


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Old 8th August 2011, 00:51   #366  |  Link
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Quote:
Originally Posted by manolito View Post
According to Selur's post the sox remix values for stereo downmix of a 6ch source should be:

1v0.3694+3v0.2612+4v0.3694 2v0.3694+3v0.2612+5v0.3694

Note that only channels 1,3,4 are used for the left channel, 2,3,5 for the right channel.
These numbers can not refer to the Default Channel Ordering for WAVE files!

Otherwise he would be mixing "LFE" into the Left channel only, mixing "Back Left" into the Right channel only and not using "Back Right" at all - which wouldn't make much sense

Instead I assume he is mixing "Back Left" into Left, "Back Right" into Right and leaving out the LFE channel completely.

Except for the LFE and the different weights (it seems he is using the same weight for "main" and "back" plus some bias to the "center"), that is identical to my choice.
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Last edited by LoRd_MuldeR; 8th August 2011 at 02:51.
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Old 8th August 2011, 03:09   #367  |  Link
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Latest Beta on http://sourceforge.net/projects/lame...29/2011-08-07/ is BROKEN. When I click to download files, nothing happened, just redirects me on other page...please fix it or give us others links.
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Old 8th August 2011, 03:17   #368  |  Link
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Quote:
Originally Posted by Romario View Post
Latest Beta on http://sourceforge.net/projects/lame...29/2011-08-07/ is BROKEN. When I click to download files, nothing happened, just redirects me on other page...please fix it or give us others links.
Please read the comment above:
http://forum.doom9.org/showpost.php?...&postcount=362

There are more reports of problems with the SourceForge file release system:
http://sourceforge.net/apps/trac/sou...e/ticket/21078
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Old 8th August 2011, 03:17   #369  |  Link
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This is old news...
Quote:
I can confirm. Looks like a problem at SourceForge.net. The file was uploaded hours ago, but is only available from one single mirror ("Waix") at this time.

And even that mirror doesn't seems to work, it just redirects to the "Files" page. Anyway, you can use Auto-Update for now...
Just use Auto-Update


Cheers
manolito


//Edit
Oops. MuldeR was faster than me...
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Old 8th August 2011, 13:28   #370  |  Link
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Quote:
Originally Posted by LoRd_MuldeR View Post
Please read the comment above:
http://forum.doom9.org/showpost.php?...&postcount=362

There are more reports of problems with the SourceForge file release system:
http://sourceforge.net/apps/trac/sou...e/ticket/21078
Seems like the problem has been fixed.

Works for me:
http://sourceforge.net/projects/lame...8.exe/download
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Last edited by LoRd_MuldeR; 8th August 2011 at 15:57.
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Old 8th August 2011, 22:13   #371  |  Link
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LameXP v4.03 Alpha-10:

Quote:
Changes between v4.02 and v4.03:
* Added an option to rename the output files (based on an user-defined pattern)
* Added an option to enforce Stereo Downmix for Multi-Channel sources
* Added "built-in" WMA decoder (see this thread for details) and removed all remnants of "old" decoder
* Added a menu for bookmarking "favorite" output folders to the "output folder" tab
* Updated Qt runtime libraries to v4.8.0 Beta-1 (2011-07-19), compiled with MSVC 10.0
* Updated MediaInfo to v0.7.47 (2011-07-27), compiled with MSVC 10.0
* Updated language files (big thank-you to all contributors !!!)
* Improved "downmix" filter by using explicit channel mappings for each number of input channels
* Fixed Cue Sheet import for tracks with certain characters in the title
* Workaround for malicious "anti-virus" programs that prevent innocent applications from functioning
* Enabled "Aero Glass" theme in installer and web-update program (Vista and Windows 7 only)
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Last edited by LoRd_MuldeR; 21st August 2011 at 15:54.
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Old 9th August 2011, 02:25   #372  |  Link
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Ok,it's work now. Thank you for your explanation.
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Old 9th August 2011, 05:16   #373  |  Link
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Some more thoughts about downmixing:

http://ac3filter.net/wiki/Mixing_matrix
According to this the downmix volumes should be "normalized" to avoid clipping.

http://www.surroundassociates.com/tapeprep.html
http://www.ocularstudio.com/why-surr...ereo-or-quadro

According to these two links channel assignment for DTS is often different.

What do we do when downmixing DTS sources? Valdec decodes DTS in LameXP, does it reassign the channels to the "standard" assignment?


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Old 9th August 2011, 12:41   #374  |  Link
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Quote:
Originally Posted by manolito View Post
Some more thoughts about downmixing:

http://ac3filter.net/wiki/Mixing_matrix
According to this the downmix volumes should be "normalized" to avoid clipping.
That's what SoX does by default. When mixing together n channels, the volume of each channel is reduced to 1/n.

So in sum the volume cannot exceed 1.0, which prevents clipping.

When using "custom" weights you have to take care that the sum of all weights (per channel) is 1.0 or below. Otherwise clipping is possible.

Of course I tried to choose weights that exactly match 1.0 in sum

Quote:
Originally Posted by manolito View Post
According to these two links channel assignment for DTS is often different.

What do we do when downmixing DTS sources? Valdec decodes DTS in LameXP, does it reassign the channels to the "standard" assignment?
Well, when implementing a "downmix" filter some channel mapping has to be assume.

As said before, LameXP now assumes the "Default Channel Ordering" for multiple channel WAVE files.

I think any decoder which outputs WAVE files is supposed to use that channel mapping...

(In theory different channel mappings could be used/assumed, depending on the individual input format or decoder of the current file.
But at the moment the "dowmix" filter doesn't know about input formats. And, in a well-designed system, it shouldn't have to!)
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Last edited by LoRd_MuldeR; 9th August 2011 at 14:24.
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Old 15th August 2011, 23:15   #375  |  Link
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LameXP v4.03 Alpha-12:

Quote:
Changes between v4.02 and v4.03:
* Added an option to rename the output files (based on an user-defined pattern)
* Added an option to enforce Stereo Downmix for Multi-Channel sources
* Added "built-in" WMA decoder (see this thread for details) and removed all remnants of "old" decoder
* Added a menu for bookmarking "favorite" output folders to the "output folder" tab
* Updated Qt runtime libraries to v4.8.0 Beta-1 (2011-07-19), compiled with MSVC 10.0
* Updated MediaInfo to v0.7.47 (2011-07-27), compiled with MSVC 10.0
* Updated language files (big thank-you to all contributors !!!)
* Improved "downmix" filter by using explicit channel mappings for each number of input channels
* Fixed Cue Sheet import for tracks with certain characters in the title
* Workaround for malicious "anti-virus" programs that prevent innocent applications from functioning
* Enabled "Aero Glass" theme in installer and web-update program (Vista and Windows 7 only)
* Restored Windows 2000 support with Visual Studio 2010 (this is experimental!)
Seems like I finally figured out a feasible way to make Visual Studio 2010 binaries run on Windows 2000:
http://mulder.googlecode.com/svn/tru...Lib/README.txt

(And yes, I am well aware that the EncodeDecodePointer substitute function does not provide the extra "protection" of the original implementation)
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Last edited by LoRd_MuldeR; 21st August 2011 at 15:38.
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Old 19th August 2011, 16:55   #376  |  Link
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LameXP v4.03 Alpha-13:

This version adds experimental support for the FHG AAC Encoder that is included with latest Winamp.
You will need the Add-in to enable the FHG AAC Encoder in LameXP. See the included instructions!
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Old 19th August 2011, 23:07   #377  |  Link
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Just out of curiosity:
Do you think that the FHG AAC encoder has an edge over Nero?
(HydrogenAudio is conducting a listening test, but no results so far...)


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Old 19th August 2011, 23:15   #378  |  Link
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Quote:
Originally Posted by manolito View Post
Just out of curiosity:
Do you think that the FHG AAC encoder has an edge over Nero?
I will leave that decision up to the users. Haven't done any comprehensive tests yet.
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Old 21st August 2011, 15:54   #379  |  Link
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LameXP v4.03 Alpha-14:

Quote:
Changes between v4.02 and v4.03:
* Added an option to rename the output files (based on an user-defined pattern)
* Added an option to enforce Stereo Downmix for Multi-Channel sources
* Added "built-in" WMA decoder (see this thread for details) and removed all remnants of "old" decoder
* Added optional support for the FHG AAC Encoder (see the FAQ doc for install instructions!)
* Added a menu for bookmarking "favorite" output folders to the "output folder" tab
* Updated Qt runtime libraries to v4.8.0 Beta-1 (2011-07-19), compiled with MSVC 10.0
* Updated MediaInfo to v0.7.48 (2011-08-17), compiled with MSVC 10.0
* Updated language files (big thank-you to all contributors !!!)
* Improved "downmix" filter by using explicit channel mappings for each number of input channels
* Fixed Cue Sheet import for tracks with certain characters in the title
* Workaround for malicious "anti-virus" programs that prevent innocent applications from functioning
* Enabled "Aero Glass" theme in installer and web-update program (Vista and Windows 7 only)
* Restored Windows 2000 support with Visual Studio 2010 (this is experimental!)
__________________
There was of course no way of knowing whether you were being watched at any given moment.
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Last edited by LoRd_MuldeR; 27th August 2011 at 20:43.
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Old 22nd August 2011, 12:21   #380  |  Link
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Quote:
Originally Posted by LoRd_MuldeR View Post
LameXP v4.03 Alpha-14:
* Added optional support for the FHG AAC Encoder (see the FAQ doc for install instructions!)
You may want to check this wrapper which is only 18KB, compared to the 398KB of the one you link to, and source code is included:
http://www.hydrogenaudio.org/forums/...dpost&p=763079

And in your FAQ you provide a direct link to a version of Winamp which is the German only version. You may want to link either to the English version and/or to the international version which includes German, Dutch, French, Italian, Polish, Russian, Spanish, Swedish, Korean, Japanese, Chinese, Turkish, Portuguese and Romanian languages.

Just my two cents
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