Feature request: implement processing of Finite Impulse Response (FIR) filters in the Squeezebox firmware, to enable arbitrary EQ.

I have a server-side transcode plugin (hooked into slimserver-convert.conf) for EQ and room correction.  For long filters (i.e. room correction) this is great.  For short or frequently-changed filters (i.e. EQ) this is almost unusable.  The server-side transcoder processes the stream, which is then buffered on the Squeezebox;  any changes initiated by the user (via plugin) area only heard after many seconds, due to SB's buffering.

Suggestion for a good way to fix this, and to generally enable a wide range of filter extensions:
- Implement convolution in the firmware, for short FIR filters (say, 128 tap).  Convolution = FFT, multiply by FFT of the filter, then IFFT; with overlap-and-save for linear stream processing.  FFT already exists in firmware, and short filters shouldn't break the CPU budget.  (You would need floating point math for the convolution; 32-bit is OK).  This all takes effect after any decodes (ie. on raw data).
- Have a bank of four filters.  #1: processes left in, to left out.  #2: right in - right out.  #3: left in - right out.  #4: right in - left out.  This enables cross-channel cancellation (stereo image width enhancement, etc) as well as per-channel equalization and other filtering.
- Have a client function callable by the server to install a 128 * 32-bit filter to each bank.
- Have another client function callable by the server to bypass all filters.

Then, e.g.,
my plugin displays a set of bar input controls, one for each of 9 frequency bands;  on change, it recalculates the EQ filter (which is reasonably quick), and sends the filter up to Squeezebox.