--- Steve Harris <[EMAIL PROTECTED]> wrote: > > But that puts potentially expensive gain > > calculations into the fast sr code, also I was rather planning > > on using the impulse used for the upsampler to > >provide the band limiting for free. > > the gain calculations are relativly cheap, its > converting those gain > levels back into a gain coefficient on the output > that's expensive (from > what I remember).
But all that can still be done at 44.1/48, it is only the final sample multiplication that needs its inputs band limited and thus potentially needs the upsampler. > > BEAST was the project that had the SSE 2* up/down > > sampler code that seems to be reasonably quick. > > But what interpolation function? If you something > obvious and cheap you > may as well not bother, as you wont get accurate > peak interpolation. The usual half band impulse convolution based approach. > I dont think a streaming resampler is more > challenging than a correct one > that runs on buffers. You just have to preserve > state with every call, > rather than at the buffer boundaries. But that breaks the ability to use the vectorisation capability of modern compilers and besides the call and return overhead will end up costing as much as the convolution! We seem to be discussing two separate problems here, aliasing in the gain cell and real 'audio' peak discovery, they are peripherally related byt are not the same thing. Regards Dan (Who really now has to go and do some work). Send instant messages to your online friends http://uk.messenger.yahoo.com
