tonhowtf/omniget · error

ffmpeg (mux) falhou

Error message

ffmpeg (mux) falhou: {}

What it means

The last dub step muxes the original video stream (stream-copied) with the dubbed audio (re-encoded to aac) using ffmpeg with -map 0:v -map 1:a -shortest. If ffmpeg exits non-zero, dub() raises 'ffmpeg (mux) falhou: <stderr>'. It is thrown when video+audio cannot be combined into the final output file.

Solutions

  1. Read the stderr embedded in the error message — it identifies the exact mux failure (input missing, codec/container mismatch, permission).
  2. Verify both inputs exist and are valid: the source video and the dubbed audio from the previous (final) step.
  3. Make sure the output file extension matches an ffmpeg-supported container and the directory is writable, and check free disk space.
  4. Confirm the installed ffmpeg has the AAC encoder (ffmpeg -encoders | grep aac); upgrade ffmpeg if it is missing or the video codec cannot be copied into the target container (e.g. use mkv for unusual video codecs).
Defensive patterns

Strategy: try-catch

Validate before calling

// guard before muxing: both inputs must exist
if !video_path.as_ref().exists() {
    anyhow::bail!("source video missing: {}", video_path.as_ref().display());
}
if !dub_audio.exists() {
    anyhow::bail!("dubbed audio missing: {}", dub_audio.display());
}

Try / catch

match dub(opts).await {
    Err(e) if e.to_string().starts_with("ffmpeg (mux) falhou") => {
        log::error!("mux failed: {e}");
        // suggest an .mkv output when -c:v copy fails for the container
    }
    other => other?,
}

Prevention

When it happens

Trigger: Calling dub where the mux invocation exits non-zero: the video input and dubbed audio are missing/unreadable, stream durations/parameters are irreconcilable, the output container (e.g. mp4) rejects the audio codec, or the output path is unwritable.

Common situations: Dubbed audio produced by a failed/aborted earlier step; output filename with an extension not matching the container; disk full during the final write; ffmpeg build lacking the native AAC encoder; source video with codecs -c:v copy cannot place into the chosen container.

Related errors

AI-assisted analysis of tonhowtf/omniget@8600b91f42 (2026-09-12). Data as JSON: /api/errors/3a4621e6c873d79e. Report an issue: GitHub.

Appendix: source

Thrown at src-tauri/omniget-core/src/core/tools/dub.rs:243

        let mut cmd = crate::core::process::command(&ffmpeg);
        cmd.args(["-y", "-hide_banner", "-loglevel", "error", "-i"])
            .arg(video)
            .arg("-i")
            .arg(&dub_audio);
        if opts.keep_original_volume > 0.0 {
            let f = format!(
                "[0:a]volume={:.2}[o];[1:a]volume=1.0[d];[o][d]amix=inputs=2:dropout_transition=0:normalize=0[a]",
                opts.keep_original_volume.min(1.0)
            );
            cmd.args(["-filter_complex", &f, "-map", "0:v", "-map", "[a]"]);
        } else {
            cmd.args(["-map", "0:v", "-map", "1:a"]);
        }
        cmd.args(["-c:v", "copy", "-c:a", "aac", "-shortest"])
            .arg(&out);
        let output = cmd.output().await?;
        if !output.status.success() {
            return Err(anyhow!(
                "ffmpeg (mux) falhou: {}",
                String::from_utf8_lossy(&output.stderr).trim()
            ));
        }
        video_out = Some(out.to_string_lossy().to_string());
    }
    let _ = std::fs::remove_dir_all(&work);
    super::report(&progress, id, "done", 1, Some(1), None);
    Ok(DubResult {
        audio_path: dub_audio.to_string_lossy().to_string(),
        video_path: video_out,
        cues: cues.len(),
        sped_up,
    })
}

#[cfg(test)]
mod tests {

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