Crate replaygain

Expand description

This is little more than a wrapper around the replaygain analysis functionality provided by ffmpeg’s af_replaygain. Unlike af_replaygain however, this gives you the actual values instead of just printing them to the console and then throwing them away. So close, yet so far.

Prerequisites

Stereo audio (no other channel counts supported)
Supported sample rates: 8000, 11025, 12000, 16000, 18900, 22050, 24000, 32000, 37800, 44100, 48000, 56000, 64000, 88200, 96000, 112000, 128000, 144000, 176400, 192000 (Hz)
Float encoding (endianness handled on your side)

It sure doesn’t lack irony that most users of this crate would probably actually use ffmpeg to convert their audio to a compatible format.

Usage

use replaygain::ReplayGain;
let mut rg = ReplayGain::new(44100).unwrap();
let samples = []; // get data from somewhere
rg.process_frame(&samples);
let (gain, peak) = rg.finish();

Example

use std::{env, io, slice};
use std::io::Read;
use replaygain::ReplayGain;

fn main() {
    let mut args = env::args();
    args.next().unwrap(); // executable name
    let param1 = args.next().unwrap();

    let sample_rate = param1.parse().unwrap();
    let mut rg = ReplayGain::new(sample_rate).unwrap();

    // Just buffer everything up to keep things simple
    let mut input = Vec::new();
    {
        let stdin = io::stdin();
        let mut lock = stdin.lock();
        lock.read_to_end(&mut input).unwrap();
    }

    // Quick and dirty conversion
    let floats = unsafe { slice::from_raw_parts(&input[..] as *const _ as *const f32,
                                                input.len() / 4) };
    rg.process_samples(floats);

    let (gain, peak) = rg.finish();
    println!("track_gain = {} dB", gain);
    println!("track_peak = {}", peak);
}

Structs

ReplayGain