Re: [linux-audio-user] Green's Function in Audio --- Demo Song

Hi Erik, It's actually a resampler, not merely a downsampler. I haven't read your code, nor have I used it other than in programs written by others which utilize your library, so I don't know. (And I **THANK YOU** for writing that library --- many use it.) It was easier for me to write my own than to try and determine whether or not your resampler was suitable for my particular situation. However: developed by Julius Smith of Stanford. Smith's method is very fast, but not as accurate as FFT/overlap with large windows. Without Kaiser windowing, it wouldn't have seen the light of day due to the truncation effects. I need something that preserves the phase and other information as accurately as possible between the channels, not a small-windows approximation. I need a guarantee of accuracy, and I simply didn't have the time to fully investigate the sinc method with Kaiser and other windows. I should also say that the FFT-overlap method is entirely *inappropriate* for other situations, especially where the sample rate changes a lot and/or very quickly. Here the sinc method is *very good* to *excellent*. (Actually I have my own variant of that too, which is why I chose not to use it for my own straightforward, fixed 24/96 to 16/44.1 conversions.) Why I wrote my *own* FFT-overlap resampler: A feature of all programs I write using my own class libraries is that they automatically understand stdin/out, sockets, FIFO's, and files. One program can accept data with a WAV-style header from any/all of these IPC methods, and the same program (all programs) can put out WAV data using any of these methods. So all these programs are scriptable rather than part of a library. That is, the resampler can be put into any script (bash, ksh, Python, PERL, awk) that uses those IPC mechanisms, connecting it easily with any other program that was written in the same manner or with standard UNIX utilities including the "lowly" head, tail, grep, etc. I developed this technique to allow me to rapidly create prototype programs, the downsampler script being but one of many such scripts that utilize programs that communicate via these IPC mechanisms. This technique also allows me to execute "pipelines" from the command line, which is the origin of many of my scripts. That was probably a longer answer than you anticipated, but I hope I answered your question. Again, I thank you for writing that library. I'm sure many programmers would have had a tough time without it. Again, the sinc method is really the only way to go for many (most?) programs that require resampling. Best regards, Dave.