9 Oct
2015
9 Oct
'15
3:05 p.m.
On Wed, 7 Oct 2015 13:18:53 +0200
Gérald Maruccia <gerald.maruccia(a)yahoo.fr> wrote:
Hello Carl,
yes I'm working in a commercial theatre which has 6 screens, so my tests
are in « real » situation ;-)
I have the feeling that upmixing A lowers too much the LFE channel and
gives too much room to highest frequencies.
I don't remember using -3db step for C and LFE in my experimentations ;-)
But you say you are using v0.5 as a parameter to sox Isn't that a gain
reduction of 3dB?
Using sox for distributing ranges of freq. per
channel, it looks like :
# gauche - L
sox $dft $ddt/00.wav $ddt/01.wav *remix -l sinc 1900-4800*
# droite - R
sox $dft $ddt/00.wav $ddt/02.wav *remix -r sinc 1900-4800*
# centre - C
sox $dft $ddt/00.wav $ddt/03.wav *remix 1v0.5,2v0.5 sinc 150-1900*
# basses - LFE
sox $dft $ddt/00.wav $ddt/04.wav *remix 1v0.5,2v0.5 sinc 20-150*
# ambiance gauche - Lsr
sox $dft $ddt/00.wav $ddt/05.wav *remix* *-l sinc 4800-20000*
# ambiance droite - Rsr
sox $dft $ddt/00.wav $ddt/06.wav *remix* *-r sinc 4800-20000*
where 00.wav is source stereo material, dft="-S -V" and ddt=path to
temporary folder
For C and LFE v0.5 is to get L and R at the same level, if v1 then both
are added ending in much too loud mix.
That should be what Upmixer A is doing: I copied from your method. The
only difference I can think of is in the rolloff rate of the filters.
Do you see Upmixer A giving drastically different results to your sox
method?
Hereafter another way, sounding more like a dolby
prologic mix :
# first step, get a mono mix of the stereo source for C
sox $dft -c 2 $ddt/00.wav -c 1 $ddt/mono_mix.wav *mixer 0.5,0.5*
# get one file for L, one for R
sox $dft -c 2 $ddt/00.wav -c 1 $ddt/00gauche.wav *mixer -**l*
sox $dft -c 2 $ddt/00.wav -c 1 $ddt/00droite.wav *mixer -r*
# phase inversion on L and R
# substract R from mono mix to get L/ substract L from mono mix to get R
# → this is where "human voices" almost disappear from L and R channel
unless they were mixed 100% on left or right !
sox $dft *-M -c 1 -v -1* $ddt/00droite.wav -c 1 $ddt/mono_mix.wav -c 1
$ddt/gauche.wav
sox $dft *-M -c 1 -v -1* $ddt/00gauche.wav -c 1 $ddt/mono_mix.wav -c 1
$ddt/droite.wav
# gauche - L
sox $dft -c 1 $ddt/gauche.wav -c 1 $ddt/01.wav *sinc 120-20000*
# droite - R
sox $dft -c 1 $ddt/droite.wav -c 1 $ddt/02.wav *sinc 120-20000*
# centre - C
sox $dft -c 1 $ddt/mono_mix.wav -c 1 $ddt/03.wav *sinc 120-12000*
# basses - LFE
sox $dft -c 1 $ddt/mono_mix.wav -c 1 $ddt/04.wav *sinc 20-120*
# ambiance gauche - Lsr
sox $dft -c 1 $ddt/gauche.wav -c 1 $ddt/05.wav *delay 0.02 sinc 120-6000
reverb*
# ambiance droite - Rsr
sox $dft -c 1 $ddt/droite.wav -c 1 $ddt/06.wav *delay 0.02 sinc 120-6000
reverb
That should be what Upmixer B does, more or less. Did you try it?
Regards,
Carl
*I don't pretend these are perfect but quite smooth. I had another "mix"
in the upmix script but way too loud for movies, only useful for concert
or musical video clips.
Best regards,
G.
**
Le 07/10/2015 10:31, Carl Hetherington via DCPomatic a écrit :
On Tue, 6 Oct 2015 13:03:03 +0200
Gérald Maruccia via DCPomatic <dcpomatic(a)carlh.net> wrote:
Hello !
Wow, impressive list of fixes !
* Add a new stereo to 5.1 upmixing algorithm (Upmixer B).
→ the one already in is kind of "metallic" - which is unexpected if it's
just about distributing frequency ranges into channels ?
Yes, that is a bit
strange. Are you listening in an auditorium?
→ does the new one make use of phase-inversion ?
Yes, I've just added a description of what it does here:
http://dcpomatic.com/manual/html/ch06.html
These upmixers are all somewhat experimental... it's interesting to hear how useful
any of them are.
Regards,
Carl
Best regards,
Gérald
Le 06/10/2015 01:10, Carl Hetherington via DCPomatic a écrit :
> Hi all,
>
> DCP-o-matic 2.4.0 is now available for download from:
>
> http://dcpomatic.com/download
>
> It has the following changes:
>
> * Basic support for creation of VF DCPs from imported OV DCPs.
> * Handle non-UTF-8 .srt files better.
> * Add experimental packages for Fedora 22.
> * Fix various problems with subtitle timing when video frame rates change.
> * Fix various preview problems when changing DCP frame rate (#695 and #699).
> * Fix incorrect recognition of a folder of images due to filenames beginning with
._
> * Fix failure to analyse audio of some combined video/audio files.
> * Fix subtitle errors in some cases.
> * Fix errors with .MTS files in some cases (#702).
> * Fix incorrect hint when making a 3D DCP.
> * Fix error on adjusting the audio map in some cases.
> * Fix for analysis of audio when the subject is later in the playlist than some
other long piece of content.
> * Fix encoding server shortcut on Windows.
> * Fix failure to display audio analyses in some cases.
> * Fix crash when re-making certificates after deleting existing ones (#690).
> * Fix crash on adding an empty folder as content (#691).
> * Fix non-operational image sequence frame rate dialogue.
> * Speculative fix for hangs at the end of encodes in some cases.
> * Fix subtitle timing when trimmed.
> * Add a new stereo to 5.1 upmixing algorithm (Upmixer B).
> * Allow configuration of default standard (Interop or SMPTE).
> * Speed up checking of existing image data when resuming transcodes.
> * Add a frame counter to transcode progress (#111).
> * Add export button for certificates.
> * Display peak audio value in the audio tab if an analysis has been done.
> * Add option to analyse audio automatically when it is added (#673).
> * Mark SCP as being the protocol for Doremi as well as AAM (#678).
>
> Thanks to Mirjam Bromundt and Thierry Journet.
>
> Best regards,
> Carl
>
>
> _______________________________________________
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