Struct Config 

pub struct Config {
    pub chunk_duration_secs: usize,
    pub model: String,
    pub endpoint: String,
    pub out_file: Option<PathBuf>,
    pub on_device: Option<OnDeviceConfig>,
}

Configuration for the transcription service.

This struct controls how audio is captured, chunked, and sent to the transcription API. All fields have sensible defaults and can be loaded from a JSON configuration file.

Examples

Using defaults

use vtt_rs::Config;

let config = Config::default();
assert_eq!(config.chunk_duration_secs, 5);
assert_eq!(config.model, "whisper-1");

Custom configuration

use vtt_rs::Config;
use std::path::PathBuf;

let config = Config {
    chunk_duration_secs: 3,
    model: "whisper-1".to_string(),
    endpoint: "https://api.openai.com/v1/audio/transcriptions".to_string(),
    out_file: Some(PathBuf::from("output.log")),
};

Loading from JSON file

use vtt_rs::Config;

let config = Config::from_file("config.json")?;

Fields

chunk_duration_secs: usize

Duration of each audio chunk in seconds.

Smaller values (2-3 seconds) provide faster response times but may reduce accuracy. Larger values (5-10 seconds) improve accuracy but increase latency.

model: String

OpenAI model to use for transcription.

Common values: "whisper-1" for OpenAI’s Whisper model.

endpoint: String

API endpoint for transcription requests.

Defaults to OpenAI’s endpoint but can be changed to support local Whisper instances or other OpenAI-compatible APIs.

out_file: Option<PathBuf>

Optional file path to append transcription logs.

When set, all transcriptions (including silence markers) will be written to this file in addition to being sent via events. Use None to disable file logging.

on_device: Option<OnDeviceConfig>

Optional on-device configuration.

When present and enabled, the service will run Whisper locally using the bundled Candle integration instead of calling a remote API.

Implementations

impl Config

pub fn from_file(path: impl AsRef<Path>) -> Result<Self>

Loads configuration from a JSON file at the specified path.

The JSON file should contain fields matching the Config struct. Missing fields will use their default values via serde’s #[serde(default)].

Examples

use vtt_rs::Config;

let config = Config::from_file("my_config.json")?;
println!("Using model: {}", config.model);

Errors

Returns an error if:

• The file cannot be read
• The file contains invalid JSON
• The JSON structure doesn’t match the expected format

pub fn load_or_default() -> Result<(Self, Option<PathBuf>)>

Attempts to load configuration from vtt.config.json in the current directory.

If the default config file exists, it will be loaded. Otherwise, returns default configuration values.

Examples

use vtt_rs::Config;

let (config, source_path) = Config::load_or_default()?;

if let Some(path) = source_path {
    println!("Loaded config from: {}", path.display());
} else {
    println!("Using default configuration");
}

Errors

Returns an error if the default config file exists but cannot be read or parsed.

pub fn resolve_out_path(&self, source: Option<&Path>) -> Option<PathBuf>

Resolves the output file path relative to the configuration file’s location.

This method handles both absolute and relative paths in out_file:

• Absolute paths are returned as-is
• Relative paths are resolved relative to the config file’s directory
• If no source path is provided, relative paths remain unchanged

Examples

use vtt_rs::Config;
use std::path::{Path, PathBuf};

let mut config = Config::default();
config.out_file = Some(PathBuf::from("logs/output.log"));

let source = Path::new("/etc/vtt/config.json");
let resolved = config.resolve_out_path(Some(source));

assert_eq!(resolved, Some(PathBuf::from("/etc/vtt/logs/output.log")));

pub fn uses_on_device(&self) -> bool

Returns true when on-device transcription is enabled.

pub fn on_device_config(&self) -> Option<&OnDeviceConfig>

Returns the enabled on-device configuration if present.

Trait Implementations

impl Clone for Config

fn clone(&self) -> Config

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Config

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

Formats the value using the given formatter.

impl Default for Config

fn default() -> Self

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Config

where Config: Default,

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.