Struct GainOptions 

pub struct GainOptions { /* private fields */ }

Options for applying gain adjustment to an MP3 file.

Use the builder pattern to configure how gain should be applied:

use mp3rgain::GainOptions;
use std::path::Path;

// Simple gain adjustment (+3 dB = 2 steps)
GainOptions::new(2).apply(Path::new("song.mp3")).unwrap();

// Gain in dB with undo support
GainOptions::from_db(4.5).undo(true).apply(Path::new("song.mp3")).unwrap();

// Wrapping mode with undo
GainOptions::new(5).wrap(true).undo(true).apply(Path::new("song.mp3")).unwrap();

// Channel-specific gain
use mp3rgain::Channel;
GainOptions::new(3).channel(Channel::Left).undo(true).apply(Path::new("song.mp3")).unwrap();

Implementations

impl GainOptions

pub fn new(steps: i32) -> Self

Create gain options from gain steps (1 step = 1.5 dB).

Positive values increase volume, negative values decrease it.

pub fn from_db(db: f64) -> Self

Create gain options from a dB value (rounded to nearest step).

pub fn wrap(self, wrap: bool) -> Self

Use wrapping mode instead of saturating (values wrap around 0-255 range).

Default is saturating mode (values clamp to 0-255). Note: wrapping mode is ignored for channel-specific gain (always saturating).

pub fn undo(self, undo: bool) -> Self

Store undo information in APEv2 tag for later reversal.

pub fn channel(self, channel: Channel) -> Self

Apply gain to a specific channel only (Left or Right).

Returns an error if the file is mono.

pub fn apply(&self, file_path: &Path) -> Result<usize>

Apply the configured gain adjustment to the given MP3 file.

Returns the number of frames modified.

pub fn apply_to_path(&self, read_from: &Path, write_to: &Path) -> Result<usize>

Apply the configured gain adjustment, reading from read_from and writing to write_to. When the two paths are the same, this is equivalent to [apply].

Used by the --temp-file (-t) path so that the modified audio is written directly to the temp file without an intermediate full-file copy of the original (issue #135).

Trait Implementations

impl Clone for GainOptions

fn clone(&self) -> GainOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for GainOptions

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

Formats the value using the given formatter.