Struct AudioFormatConverter 

pub struct AudioFormatConverter;

High-level audio format converter.

Detects common audio container formats and converts WAV/PCM input to the standard format: mono, 16kHz, normalized f32 samples.

Pipeline Architecture

Input Bytes
    ↓
[Format Detection] ← 6 formats: WAV, MP3, FLAC, Opus, WebM, AAC
    ↓
[WAV Decoding] ← 16/24-bit PCM normalization
    ↓
[Resampling] ← Arbitrary rate → 16kHz (linear interpolation)
    ↓
[Channel Mixing] ← Multi-channel → Mono (simple averaging)
    ↓
StandardAudio (mono, 16kHz, f32)

Current Scope Limitations

• Formats: Only WAV decoding implemented; other formats detected but not decoded
• Channel Counts: 1, 2, 4, 6 channels supported
• Bit Depths: 16-bit and 24-bit PCM only
• Resampling: Linear interpolation (sinc reserved for future)

Example

use speech_prep::converter::AudioFormatConverter;

let wav_bytes = std::fs::read("audio.wav")?;
let standard = AudioFormatConverter::convert_to_standard(&wav_bytes)?;

assert!(standard.metadata.original_sample_rate > 0);
assert!(standard.metadata.original_channels > 0);

Implementations

impl AudioFormatConverter

pub const fn new() -> Self

Create a new audio format converter instance.

pub fn convert_to_standard(audio_bytes: &[u8]) -> Result<StandardAudio>

Convert WAV audio bytes to standard format: mono, 16kHz, f32.

This is the primary entry point for the audio normalization pipeline. It composes all 4 stages: format detection, decoding, resampling, and channel mixing.

Arguments

• audio_bytes - Raw audio file bytes

Returns

StandardAudio with mono 16kHz samples and complete conversion metadata.

Errors

Returns Error::InvalidInput if:

• Format detection fails (not a recognized audio format)
• Format is detected but not WAV (only WAV decoding supported)
• WAV decoding fails (malformed file, unsupported codec)
• Resampling fails (invalid sample rates)
• Channel mixing fails (unsupported channel count)

Performance

Target: <10ms for 3-second audio clip on reference hardware. Actual timing captured in ConversionMetadata.conversion_time_ms.

Example

use speech_prep::converter::AudioFormatConverter;

let audio_bytes = std::fs::read("recording.wav")?;
let standard = AudioFormatConverter::convert_to_standard(&audio_bytes)?;

assert_eq!(standard.metadata.original_format.as_str(), "wav");
assert!(standard.samples.len() > 0);

Trait Implementations

impl Clone for AudioFormatConverter

fn clone(&self) -> AudioFormatConverter

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for AudioFormatConverter

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for AudioFormatConverter

fn default() -> AudioFormatConverter

Returns the “default value” for a type.

impl Copy for AudioFormatConverter