8月1日的SpecStream Audio Spectrum Plot应用程序分析

App gets audio data from microphone and plots the real time spectrum in the form of a scrolling image. App settings: • Sample Rate = the sample rate (in Hz) at which the microphone will be read. Most devices support up to 48 kHz. High-end devices support up to 192 kHz. • FFT Buffer Size = the size (in samples) of the audio buffer used to compute the FFT. Must be a power of 2, min = 128, max = 16384. Bigger value gives better frequency resolution. Smaller value gives better time resolution. • Min. Dispalyed Frequency • Max. Displayed Frequency • Gain (dB) • Displayed Time Window (in milliseconds) • Frequency Grid Step (in Hz) = will draw horizontal division lines • Time Grid Step (in milliseconds) = will draw vertical division lines moving together with the plot. Free version limitations: • sample rate = 8000 Hz (fixed) • FFT buffer size = 512 (fixed) Users can upgrade to Premium Version via in-app purchase (one time payment). Premium version advantages: • configurable sample rate. • configurable FFT buffer size: 128, 256, 512, 1024, 2048, 4096, 8192, 16384. Planned features for future app updates: • show spectrum of audio file • export spectrum to file