Struct AudioReplacement 

pub struct AudioReplacement { /* private fields */ }

Replace a video file’s audio track with audio from a separate source file.

The video bitstream is copied bit-for-bit (no decode/encode cycle). The audio track from audio_input replaces any existing audio in video_input.

Returns RemuxError::OperationFailed when no audio stream is found in audio_input, or no video stream is found in video_input.

Example

use ff_remux::AudioReplacement;

AudioReplacement::new("source.mp4", "new_audio.aac", "output.mp4").run()?;

Implementations

impl AudioReplacement

pub fn new( video_input: impl Into<PathBuf>, audio_input: impl Into<PathBuf>, output: impl Into<PathBuf>, ) -> Self

Create a new AudioReplacement.

• video_input — source file whose video stream is kept.
• audio_input — source file whose first audio stream is used.
• output — path for the combined output file.

Examples found in repository

examples/audio_replacement.rs (line 57)

fn main() {
    let mut args = std::env::args().skip(1);
    let mut video = None::<String>;
    let mut audio = None::<String>;
    let mut output = None::<String>;

    while let Some(flag) = args.next() {
        match flag.as_str() {
            "--video" | "-v" => video = Some(args.next().unwrap_or_default()),
            "--audio" | "-a" => audio = Some(args.next().unwrap_or_default()),
            "--output" | "-o" => output = Some(args.next().unwrap_or_default()),
            other => {
                eprintln!("Unknown flag: {other}");
                process::exit(1);
            }
        }
    }

    let video = video.unwrap_or_else(|| {
        eprintln!("Usage: audio_replacement --video <file> --audio <file> --output <file>");
        process::exit(1);
    });
    let audio = audio.unwrap_or_else(|| {
        eprintln!("--audio is required");
        process::exit(1);
    });
    let output = output.unwrap_or_else(|| {
        eprintln!("--output is required");
        process::exit(1);
    });

    println!("Video source: {video}");
    println!("Audio source: {audio}");
    println!("Output:       {output}");
    println!();
    println!("Replacing audio track (stream-copy, no re-encode)…");

    AudioReplacement::new(&video, &audio, &output)
        .run()
        .unwrap_or_else(|e| {
            eprintln!("Error: {e}");
            process::exit(1);
        });

    let size = match std::fs::metadata(&output) {
        Ok(m) => {
            #[allow(clippy::cast_precision_loss)]
            let kb = m.len() as f64 / 1024.0;
            if kb < 1024.0 {
                format!("{kb:.0} KB")
            } else {
                format!("{:.1} MB", kb / 1024.0)
            }
        }
        Err(_) => "(unknown size)".to_string(),
    };

    println!("Done. {output}  {size}");
}

pub fn run(self) -> Result<(), RemuxError>

Execute the audio replacement operation.

Errors

• RemuxError::OperationFailed if video_input has no video stream or audio_input has no audio stream.
• RemuxError::Ffmpeg if any FFmpeg API call fails.

Examples found in repository

examples/audio_replacement.rs (line 58)

fn main() {
    let mut args = std::env::args().skip(1);
    let mut video = None::<String>;
    let mut audio = None::<String>;
    let mut output = None::<String>;

    while let Some(flag) = args.next() {
        match flag.as_str() {
            "--video" | "-v" => video = Some(args.next().unwrap_or_default()),
            "--audio" | "-a" => audio = Some(args.next().unwrap_or_default()),
            "--output" | "-o" => output = Some(args.next().unwrap_or_default()),
            other => {
                eprintln!("Unknown flag: {other}");
                process::exit(1);
            }
        }
    }

    let video = video.unwrap_or_else(|| {
        eprintln!("Usage: audio_replacement --video <file> --audio <file> --output <file>");
        process::exit(1);
    });
    let audio = audio.unwrap_or_else(|| {
        eprintln!("--audio is required");
        process::exit(1);
    });
    let output = output.unwrap_or_else(|| {
        eprintln!("--output is required");
        process::exit(1);
    });

    println!("Video source: {video}");
    println!("Audio source: {audio}");
    println!("Output:       {output}");
    println!();
    println!("Replacing audio track (stream-copy, no re-encode)…");

    AudioReplacement::new(&video, &audio, &output)
        .run()
        .unwrap_or_else(|e| {
            eprintln!("Error: {e}");
            process::exit(1);
        });

    let size = match std::fs::metadata(&output) {
        Ok(m) => {
            #[allow(clippy::cast_precision_loss)]
            let kb = m.len() as f64 / 1024.0;
            if kb < 1024.0 {
                format!("{kb:.0} KB")
            } else {
                format!("{:.1} MB", kb / 1024.0)
            }
        }
        Err(_) => "(unknown size)".to_string(),
    };

    println!("Done. {output}  {size}");
}