SonixResampler

High-quality audio resampling using libsamplerate for converting between sample rates.

Quick Start

Kotlin

// Resample from 44100 Hz to 16000 Hz
val resampled: FloatArray = SonixResampler.resample(
    samples = audioSamples,
    fromRate = 44100,
    toRate = 16000
)

Swift

// Resample from 44100 Hz to 16000 Hz
let resampled: [Float] = SonixResampler.resample(
    samples: audioSamples,
    fromRate: 44100,
    toRate: 16000
)

Method

Method	Parameters	Returns	Description
resample	samples: FloatArray, fromRate: Int, toRate: Int	FloatArray	Resample audio to target rate

Parameters

Parameter	Type	Description
samples	FloatArray / [Float]	Input audio samples (mono, float in [-1.0, 1.0] range)
fromRate	Int	Source sample rate in Hz (e.g., 44100)
toRate	Int	Target sample rate in Hz (e.g., 16000)

Common Sample Rates

Rate	Use Case
16000 Hz	Calibra APIs (pitch detection, evaluation)
22050 Hz	Speech analysis
44100 Hz	CD quality, standard playback
48000 Hz	Video, professional audio

When to Use

In most cases you don't need to use SonixResampler directly — SonixDecoder.decode() resamples automatically to 16kHz by default. Use it when:

• You have raw float samples at the wrong rate
• You need a specific target rate that isn't 16kHz
• You're doing custom audio processing

// Usually NOT needed — SonixDecoder handles resampling
val audioData = SonixDecoder.decode("audio.mp3")  // Already at 16kHz

// Needed when you have raw samples from another source
val recordedAt48k: FloatArray = ...
val at16k = SonixResampler.resample(recordedAt48k, fromRate = 48000, toRate = 16000)

Quality

Uses libsamplerate (Secret Rabbit Code) which provides:

• High-quality sinc interpolation
• Minimal aliasing artifacts
• Fast performance on mobile devices

Next Steps

• SonixDecoder — Decode audio files (resamples automatically)
• SonixEncoder — Encode resampled audio to files