A batch converter from wav to mp3

Cargo.toml

[package]
name = "batch-wav2mp3"
version = "0.1.0"
edition = "2021"

[dependencies]
walkdir = "2.3.2"

main.rs

use std::env;
use std::path::PathBuf;
use std::process::Command;
use walkdir::{DirEntry, WalkDir};

fn is_wav(entry: &DirEntry) -> bool {
    if entry.file_type().is_dir() {
        return false;
    }
    let name = entry.file_name().to_str().unwrap();
    name.ends_with(".wav") && !name.starts_with(".")
}

fn convert_to_mp3(input: &String, output: &String) {
    // ffmpeg -i input.wav -c:a libmp3lame -vn -b:a 128k output.mp3
    let mut ffmpeg = Command::new("ffmpeg")
        .args(&["-i", input, "-c:a", "libmp3lame", "-vn", "-b:a", "128k", output])
        .spawn()
        .unwrap();
    ffmpeg.wait().unwrap();
}

fn check_ffmpeg() -> bool {
    let status = Command::new("which")
        .args(["ffmpeg"])
        .status()
        .unwrap();
    status.success()
}

fn main() {
    let args: Vec<String> = env::args().collect();

    if args.len() != 2 {
        println!("Error: A directory path must be set as argument.");
        return;
    }

    let dir_path = PathBuf::from(args[1].clone());
    if !dir_path.is_dir() {
        println!("Error: Specified path is not directory.");
        return;
    }

    if !check_ffmpeg() {
        println!("Error: ffmpeg not found.");
        return;
    }

    let wav_files = WalkDir::new(dir_path.to_str().unwrap())
        .into_iter()
        .filter_map(|e| {
            if !is_wav(&e.as_ref().unwrap()) {
                None
            } else {
                e.ok()
            }
        })
        .map(|e| e.path().to_str().unwrap().to_string())
        .collect::<Vec<String>>();

    println!("wav file count: {}", wav_files.len());

    for wav in wav_files.iter() {
        let output = wav.replace(".wav", ".mp3");
        convert_to_mp3(wav, &output);
    }
}