conversion slow with bundled ffmpeg binary

[mh4ck]

Why is running ffmpeg from this package is more than double so slow than running the command directly on the Machine?

I can't find any solution for this.

If i run the following code it takes 35s to convert a 13min webm video to mp3.
If i run the command logged in the "start" event directly on my machine it takes only 14s

const moment = require("moment");
const ffmpegStatic = require("ffmpeg-static");
const ffmpeg = require("fluent-ffmpeg");
ffmpeg.setFfmpegPath(ffmpegStatic);

let outfile = fs.createWriteStream("music.mp3");
let infile = fs.createReadStream("video");

let startTime = moment().unix();
ffmpeg()
    .input(infile)
    .outputOptions([
        "-f mp3",
        "-vn",
        "-b:a 192k",
    ])
    .on('start', (commandLine) => {
      console.log(commandLine);
    })
    .on('error', (err, stdout, stderr) => {
        console.log(err);
    })
    .on('progress', (info) => {
        //console.log(info);
    })
    .on("end", () => {
        let endTime = moment().unix();
        console.log("Finished after " + (endTime - startTime) + "s");
    })
    .pipe(outfile);

[derhuerst]

If i run the command logged in the "start" event directly on my machine it takes only 14s

How do you run it? Using the same ffmpeg binary? With the same arguments?

[derhuerst]

I'm just guessing here, but it might be slower because, in the Node.js process, you're reading the input file from disk and writing it to its stdout; Then, you let the ffmpeg process read it from stdin. Same with the output file, just flipped. This setup might have bottlenecks:

• ffmpeg won't be able to seek the input file. This may be necessary to the job in a more efficient way.
• The data has to be passed around (even copied?) several times. This may lead to a significant overhead with large files.

[mh4ck]

Hi thank you for your answer.

At first: No i haven't used the ffmpeg binary, for the console test, located in the node modules i used the local installed version.

I tried now the ffmpeg-static binary without nodejs and got the same result like with nodejs. It takes 35s.

So then is the question, why is the ffmpeg static library so slow? What is the difference and how can i speed it up?

[derhuerst]

So then is the question, why is the ffmpeg static library so slow? > What is the difference and how can i speed it up?

Not sure. All ffmpeg-static does is download a pre-built binary.

Before reporting this to the respective person publishing the binaries, please double-check your setup, make sure you‘re comparing the same ffmpeg versions, running in the same environment (e.g. no Docker, WSL, etc). Also, try running ffmpeg in verbose mode to find out if it uses hardware acceleration or not.

Once you‘ve confirmed a performance difference, report it with all details about your setup: OS & its version, ffmpeg version, flags used, CPUs & GPUs in your system etc.

[derhuerst]

I'm going to close this Issue, because it seems that I cannot fix it here in ffmpeg-static.