replaygain-rs

Analyze audio data to get the ReplayGain tags (gain, peak).

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.

Documentation

lib.rs:

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);
}