[linux-audio-dev] Hi, is it possible to record multi channel speech audio and down sample it 2 stereo channels BUT with horizontal audio positioning of each audio channel ie. like dolby surround effect. I'm not looking to make multi channel podcast, just a plain stere
13 Mar
2007
13 Mar
'07
6:44 a.m.
On 13 Mar 2007, at 09:15, Valent Turkovic wrote:
Hi,
is it possible to record multi channel speech audio and down sample it
2 stereo channels BUT with horizontal audio positioning of each audio
channel ie. like dolby surround effect.
Sure, but you might be disappointed by the results, Pro Logic is not
very sophisticated (eg. there's no separate rear left and right
channel, and the bandwidth is limited). Also the only free software
implementation that I know of is not state of the art, partly due to
patent problems, and partly due to lack of interest.
There's a LADSPA plugin: http://plugin.org.uk/ladspa-swh/docs/ladspa-
swh.html#id1401
which does Pro Logic matrix encoding, you will need some other
software to mix your independent streams into LCR channels (you can
do it by ear with a 3+ variable send bus mixer), but once you have
that you can feed it to the plugin and get a pro logic compatible
stream out.
PS ignore the documentation, it has been tested, and it does work,
just not brilliantly. You will get better results if you EQ the mics
a bit to cut the level of the highs and lows a bit, especially in the
rear channel.
You would get much better results with an ambisonic stream, but I
don't /think/ you can make stereo-compatible ambisonic streams, and
not many people have ambisonic decoders. Other people on this list
know a lot more about ambisonics though.
- Steve
14 Mar
14 Mar
7:10 a.m.
New subject: [linux-audio-dev] 2-channel stereo compatible ambisonics...
Steve Harris wrote:
On 13 Mar 2007, at 09:15, Valent Turkovic wrote:
i'm very new to ambisonics, so i may be wrong, but i think there are
indeed stereo compatible first-order ambisonics streams. iirc, the
format is called UHJ, and it matrixes WXY (lossily) into L/R (i.e. no
height information).
i've changed the subject to bait fons :-D
if we're lucky he knows an implementation of 2-channel UHJ.
i found this article: http://www.ambisonic.net/ambi_AM91.html
but it does not give details as to how the matrix encoding is accomplished.
regards,
jörn
Hi,
is it possible to record multi channel speech audio and down sample it
2 stereo channels BUT with horizontal audio positioning of each audio
channel ie. like dolby surround effect.
Sure, but you might be disappointed by the results, Pro Logic is not
very sophisticated (eg. there's no separate rear left and right channel,
and the bandwidth is limited). Also the only free software
implementation that I know of is not state of the art, partly due to
patent problems, and partly due to lack of interest.
There's a LADSPA plugin:
http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#id1401
which does Pro Logic matrix encoding, you will need some other software
to mix your independent streams into LCR channels (you can do it by ear
with a 3+ variable send bus mixer), but once you have that you can feed
it to the plugin and get a pro logic compatible stream out.
PS ignore the documentation, it has been tested, and it does work, just
not brilliantly. You will get better results if you EQ the mics a bit to
cut the level of the highs and lows a bit, especially in the rear channel.
You would get much better results with an ambisonic stream, but I don't
/think/ you can make stereo-compatible ambisonic streams, and not many
people have ambisonic decoders. Other people on this list know a lot
more about ambisonics though.
9:02 a.m.
New subject: [linux-audio-dev] 2-channel stereo compatible ambisonics...
On 14 Mar 2007, at 10:10, Joern Nettingsmeier wrote:
Steve Harris wrote:
Hi Joern,
Hmm, interesting, though it sounds like you'd need a specialised UHJ
ambisonic decoder to play it back. That probably narrows the audience
even further.
- Steve
On 13 Mar 2007, at 09:15, Valent Turkovic wrote:
i'm very new to ambisonics, so i may be wrong, but i think there
are indeed stereo compatible first-order ambisonics streams. iirc,
the format is called UHJ, and it matrixes WXY (lossily) into L/R
(i.e. no height information).
i've changed the subject to bait fons :-D
if we're lucky he knows an implementation of 2-channel UHJ.
i found this article: http://www.ambisonic.net/ambi_AM91.html
but it does not give details as to how the matrix encoding is
accomplished. Hi,
is it possible to record multi channel speech audio and down
sample it
2 stereo channels BUT with horizontal audio positioning of each
audio
channel ie. like dolby surround effect.
Sure, but you might be disappointed by the
results, Pro Logic is
not very sophisticated (eg. there's no separate rear left and
right channel, and the bandwidth is limited). Also the only free
software implementation that I know of is not state of the art,
partly due to patent problems, and partly due to lack of interest.
There's a LADSPA plugin: http://plugin.org.uk/ladspa-swh/docs/
ladspa-swh.html#id1401
which does Pro Logic matrix encoding, you will need some other
software to mix your independent streams into LCR channels (you
can do it by ear with a 3+ variable send bus mixer), but once you
have that you can feed it to the plugin and get a pro logic
compatible stream out.
PS ignore the documentation, it has been tested, and it does work,
just not brilliantly. You will get better results if you EQ the
mics a bit to cut the level of the highs and lows a bit,
especially in the rear channel.
You would get much better results with an ambisonic stream, but I
don't /think/ you can make stereo-compatible ambisonic streams,
and not many people have ambisonic decoders. Other people on this
list know a lot more about ambisonics though.
15 Mar
15 Mar
10 a.m.
New subject: [linux-audio-dev] 2-channel stereo compatible ambisonics...
Steve Harris wrote:
On 14 Mar 2007, at 10:10, Joern Nettingsmeier wrote:
unless i'm very much mistaken, UHJ-encoded material can be played back
on any stereo rig without problems (some even report better stereo width
and precision). the only drawback i heard about is that UHJ-encoded
stuff tends to be a little on the ambient site, with a tad too much
reverb when listened to over stereo...
i'm very new to ambisonics, so i may be
wrong, but i think there are
indeed stereo compatible first-order ambisonics streams. iirc, the
format is called UHJ, and it matrixes WXY (lossily) into L/R (i.e. no
height information).
Hi Joern,
Hmm, interesting, though it sounds like you'd need a specialised UHJ
ambisonic decoder to play it back. That probably narrows the audience
even further. 
10:20 a.m.
New subject: [linux-audio-dev] 2-channel stereo compatible ambisonics...
On Thu, Mar 15, 2007 at 02:00:46PM +0100, Joern Nettingsmeier wrote:
unless i'm very much mistaken, UHJ-encoded
material can be played back
on any stereo rig without problems (some even report better stereo width
and precision).
Correct.
the only drawback i heard about is that UHJ-encoded
stuff tends to be a little on the ambient site, with a tad too much
reverb when listened to over stereo...
Yes, because the balance was made for surround listening wich tolerates
and even requires more reverb.
But if this is for headphone listening only then Ambisonic encoding
is probably not the best choice.
For the original problem, you can get very good result with conventional
stereo panning provided you add some room ambiance with early relections
*dependent on source position*. Same for HRTF - the virtual room adds
a lot to the realism.
--
FA
Follie! Follie! Delirio vano è questo !
6:59 p.m.
New subject: [linux-audio-dev] 2-channel stereo compatible ambisonics...
On Wed, 2007-03-14 at 11:10 +0100, Joern Nettingsmeier wrote:
Steve Harris wrote:
There's a supercollider implementation in the joshugens packages
(UHJ.sc). It is meant to be played in stereo (ie: you "sorta" decode
ambisonics b format to stereo).
It's here, you can download the source from svn:
http://sourceforge.net/projects/sc3-plugins/
-- Fernando
On 13 Mar 2007, at 09:15, Valent Turkovic wrote:
i'm very new to ambisonics, so i may be wrong, but i think there are
indeed stereo compatible first-order ambisonics streams. iirc, the
format is called UHJ, and it matrixes WXY (lossily) into L/R (i.e. no
height information).
i've changed the subject to bait fons :-D
if we're lucky he knows an implementation of 2-channel UHJ.
i found this article: http://www.ambisonic.net/ambi_AM91.html
but it does not give details as to how the matrix encoding is accomplished. Hi,
is it possible to record multi channel speech audio and down sample it
2 stereo channels BUT with horizontal audio positioning of each audio
channel ie. like dolby surround effect.
Sure, but you might be disappointed by the results, Pro Logic is not
very sophisticated (eg. there's no separate rear left and right channel,
and the bandwidth is limited). Also the only free software
implementation that I know of is not state of the art, partly due to
patent problems, and partly due to lack of interest.
There's a LADSPA plugin:
http://plugin.org.uk/ladspa-swh/docs/ladspa-swh.html#id1401
which does Pro Logic matrix encoding, you will need some other software
to mix your independent streams into LCR channels (you can do it by ear
with a 3+ variable send bus mixer), but once you have that you can feed
it to the plugin and get a pro logic compatible stream out.
PS ignore the documentation, it has been tested, and it does work, just
not brilliantly. You will get better results if you EQ the mics a bit to
cut the level of the highs and lows a bit, especially in the rear channel.
You would get much better results with an ambisonic stream, but I don't
/think/ you can make stereo-compatible ambisonic streams, and not many
people have ambisonic decoders. Other people on this list know a lot
more about ambisonics though.
6496
days inactive
6498
days old
linux-audio-dev@lists.linuxaudio.org
5 comments
4 participants
participants (4)
-
Fernando Lopez-Lezcano -
Fons Adriaensen -
Joern Nettingsmeier -
Steve Harris