https://github.com/justinzane/pulseaudio.git Alexander: Now that I have a possibly working rewind implementation, Iwanted to make sure that I understand your guidance on doing a correct LR4. Following is what I currently think I need to do: - split channels into 3 sets: lowpass, highpass, and allpass - calculate the respective biquad coefficients using a Q=0.5, with one set of coefficients for both stages of the lp/hp/ap cascades -- that is, [3][a0,a1,a2,b0,b1,b2] - use two separate data buffersfor each channel, for the first and second stages respectively -- that is, [numchannels][2][ [y0,y1,y2,w0,w1,w2] Another question I have is whether float or double are more appropriate for the actual calculations. Reducing my implementation from double to float seems wise to me for speed and space reasons on 32bit platforms, but I'm not sure that loss of precision in an IIR filter is acceptable. If you review the actual code, I know it is not done to the style standards. I am going to clean it up once I've made sure that it is fundamentally correct. Thanks for your patience while I am learning. Justin
