CodeKnight & Bitrate
Hey, I’ve been trying to squeeze a real‑time FFT into 1 ms per buffer—any tricks for keeping the latency low while still handling high sample rates?
Yeah, 1 ms is a tight squeeze, but you can hack it with a few tricks. First, keep the FFT size to the smallest power‑of‑two that still gives you the resolution you need—no need for a 4096‑point if 1024 will do. Second, don’t re‑allocate buffers every frame; pre‑allocate and just shuffle pointers. Third, use a fast FFT library that’s tuned for your CPU—FFTW or KissFFT with SIMD. If you’re on a DSP, look for hardware FFT instructions. Fourth, drop the real‑time blocking by running the FFT in a separate thread and queue the output. And don’t forget to drop the overhead of any fancy windowing or padding—just a Hamming window on the fly if you must. Keep it lean, keep it tight, and you’ll stay under that 1 ms sweet spot.
Thanks for the checklist, I’ll try those optimizations first and see how the timing looks. If the FFT thread still lags, I might need to tweak the kernel or the windowing. Appreciate the help!
No probs—just keep that fire going, and if it still hiccups, you’ll know exactly where to drop the heat. Let me know how it turns out!