[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

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
Received on Tue Mar 13 12:15:02 2007