Re: [LAD] Best way to insert DSP module in audio chain in Linux

On Mon, August 30, 2010 5:48 am, Kim Therkelsen wrote:
>
>> > I have tried loading the LADSPA-module using the module-ladspa-sink in
>> > PulseAudio but I am not sure this is the best solution.
>>
>> It is the recommended solution if you are using PA for your sound
>> server.
>
> Why is it better than loading it using the ALSA LADSPA plugin loader
> module?
> To me it seems better to load it into ALSA because it does not depend on
> whether PulseAudio is used or not.
> If it should be used in different Linux based operating systems I can not
> always rely on PulseAudio being present.
>
>> > 2) Must be able to process stereo and multichannel (5.1/7.1) formats.
>> I
>> > need the multichannel formats to perform binaural downmixing to
>> > stereo.
>>
>> I'm not sure how the dolby multichannel support is in ALSA. It may
>> depend
>> on the internal capabilities of the device.
>>
>> > So it is important that I can receive multichannel audio and mix it
>> down
>> > to stereo and output it to a stereo soundcard.
>> >
>>
>> This may better handled in app.
>
> The idea is that I perform the same processing no matter what user
> application is used to playback the audio/video.
> The plugin must receive the raw six (or eight) channel audio PCM stream.
> So I do not want to make the DSP processing specific to some special
> application only.
>

It's a noble goal but as you are attempting to cater to such a varied
range of systems that it is hard to recommend a perfect solution. You
should really isolate the core requirements and minimum apps that it will
work with then it will be easier for people to make a suggestion that fits
your needs.

-- 
Patrick Shirkey
Boost Hardware Ltd.
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