* ParserFilter: timing!

* FormatConverter: pcm to pcm
* FormatConverter: review timing

* Delay: use cyclic buffer? (less memmove() calls)
* Delay: optimize buffer usage (channels have different delays!)

* AudioDecoder: check timestamping (make test)
* AudioDecoder: customizable parsers?

* AGC: clip short bursts (?)
* AGC: limiter level
* AGC: per-channel limiter (see ac3filter support page)
* AGC: per-channel DRC 

* Mixer: throw out null columns
* Mixer: zero null output channels instead of matrixing
* Mixer: do not touch pass-through channels
* Mixer: multiply by factor if it is one output channel for one input channel
         (instead of matrixing)
?* Mixer: do not use Speakers to specify input/output modes;
   use mask and level instead. (avoid ambiguity about format and sample rate)

* New: Matrix convolution filter
* New: Winamp DSP filters host (far future)
* New: VST filters host (far future)
