[LAD] Android audio plugins

[Gabriel M. Beddingfield]

On Wed, 29 Jun 2011, Nick Copeland wrote:

>>    - LADSPA and LV2 are built to process 32-bit
>>      floating point PCM data, and have no provision
>>      for processing 16-bit integer PCM data.
>
> Do these systems actually process the floats though? I would have thought
> most of their work was moving floating point *buffers around so that other
> programs could do DSP work on them - these are plugin processors so there
> is not a great demand that they manipulate the data they move between the
> plugins (LADSPA is rather unfortunately named as in does seem to suggest
> it does DSP which it doesn't - but I will happily stand corrected here).

Most LV2 and LADSPA plugins do the DSP work in floating 
point... so... yes. :-)

But, here's what I'm getting at. Suppose you optimize your 
plugin chain for fixed-point (integer) math but use the 
current LV2 protocol.  A prosaic approach is:

   1. Synth plugin.
      generates audio.
      Converts to float.
      sends to next plugin

   2. FIR filter.
      Converts float to int.
      Processes data.
      Converts int to float.
      Sends to next plugin.

   3. Convolution Reverb
      Converts float to int.
      Processes data.
      Converts int to float.
      Sends to next plugin.

All those needless conversions don't settle right with me.


> Yes, but I don't think it has to be that big. The bigger 
> issue is why the hell would you want to do it, integrate 
> LV2 and LADSPA on to this platform?

Why would we?  Because they're mature technologies.  Why 
reinvent the wheel?

> Don't you think it is more likely that people who are interested will run
> Linux as a replacement for Android on the ARM tablets rather than have
> the apps ported over?

Maybe today, with tablets.  But not their phones.

-gabriel