audio_addition/
audio_addition.rs

1//! Add an audio track to a silent video file.
2//!
3//! Uses [`AudioAdder`] to mux a video stream with an audio stream from a
4//! separate file using stream-copy (no re-encode).  When the audio source is
5//! shorter than the video, pass `--loop` to loop the audio automatically.
6//!
7//! # Usage
8//!
9//! ```bash
10//! cargo run --example audio_addition -- \
11//!     --video  silent.mp4    \
12//!     --audio  music.mp3     \
13//!     --output with_audio.mp4
14//!
15//! # Loop short audio to cover the full video duration:
16//! cargo run --example audio_addition -- \
17//!     --video  silent.mp4    \
18//!     --audio  short.mp3     \
19//!     --output with_audio.mp4 \
20//!     --loop
21//! ```
22
23use std::process;
24
25use ff_remux::AudioAdder;
26
27fn main() {
28    let mut args = std::env::args().skip(1);
29    let mut video = None::<String>;
30    let mut audio = None::<String>;
31    let mut output = None::<String>;
32    let mut loop_audio = false;
33
34    while let Some(flag) = args.next() {
35        match flag.as_str() {
36            "--video" | "-v" => video = Some(args.next().unwrap_or_default()),
37            "--audio" | "-a" => audio = Some(args.next().unwrap_or_default()),
38            "--output" | "-o" => output = Some(args.next().unwrap_or_default()),
39            "--loop" | "-l" => loop_audio = true,
40            other => {
41                eprintln!("Unknown flag: {other}");
42                process::exit(1);
43            }
44        }
45    }
46
47    let video = video.unwrap_or_else(|| {
48        eprintln!("Usage: audio_addition --video <file> --audio <file> --output <file> [--loop]");
49        process::exit(1);
50    });
51    let audio = audio.unwrap_or_else(|| {
52        eprintln!("--audio is required");
53        process::exit(1);
54    });
55    let output = output.unwrap_or_else(|| {
56        eprintln!("--output is required");
57        process::exit(1);
58    });
59
60    println!("Video source: {video}");
61    println!("Audio source: {audio}");
62    println!("Loop audio:   {loop_audio}");
63    println!("Output:       {output}");
64    println!();
65    println!("Adding audio track (stream-copy, no re-encode)…");
66
67    let mut adder = AudioAdder::new(&video, &audio, &output);
68    if loop_audio {
69        adder = adder.loop_audio();
70    }
71
72    adder.run().unwrap_or_else(|e| {
73        eprintln!("Error: {e}");
74        process::exit(1);
75    });
76
77    let size = match std::fs::metadata(&output) {
78        Ok(m) => {
79            #[allow(clippy::cast_precision_loss)]
80            let kb = m.len() as f64 / 1024.0;
81            if kb < 1024.0 {
82                format!("{kb:.0} KB")
83            } else {
84                format!("{:.1} MB", kb / 1024.0)
85            }
86        }
87        Err(_) => "(unknown size)".to_string(),
88    };
89
90    println!("Done. {output}  {size}");
91}
audio_addition/audio_addition.rs

audio_addition/
audio_addition.rs
