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• ffmpeg : Generate empty audio and video (working for video)

  17 septembre 2021, par David Ferris

  I'm trying to generate a black video with FFMPEG. I have accomplished this with the following :

  


  ffmpeg -t 5 -f lavfi -i color=c=black:s=1920x1080 -c:v libx264 -tune stillimage -pix_fmt yuv420p out.mp4


  


  Unfortunately this video doesn't have any audio tracks. Following this, I have tried to insert -i anullsrc=channel_layout=stereo:sample_rate=44100 :

  


  ffmpeg -t 5 -i anullsrc=channel_layout=stereo:sample_rate=44100 -f lavfi -i color=c=black:s=1920x1080 -c:v libx264 -tune stillimage -pix_fmt yuv420p out.mp4


  


  Unfortunately this gives the error :

  


  


  anullsrc=channel_layout=stereo:sample_rate=44100 : No such file or
directory

  


  


  How can I modify my initial script to generate a video with empty audio ?

  


• Video player scroll doesn't work after ffmpeg audio and video merge (NodeJS)

  1er novembre 2022, par Pietro Leto

  I made youtube downloader to download video from youtube using nodejs library ytdl-core. If I wanted to download video with best quality I had to download them without sound. So, in my script, I download audio and video separately and I merge them into an mp4 file.
What's the problem ? Video player scroll doesn't work. I can see the video but I can't going back or move on, and I can't see video duration.

  


  const express = require("express");
const cors = require("cors");
const app = express();
const ffmpeg = require('ffmpeg-static');
const cp = require('child_process');
const ytdl = require("ytdl-core");

app.use(cors());

app.listen(3000, () => {
    console.log("Server is working at port 3000 !!");
});

app.get('/download', (req,res) => {
    var url = req.query.URL;
    var formato = req.query.FORMAT;

    try {
        let vid = ytdl(url,{filter:'videoonly', quality:'highestvideo'})
        let aud = ytdl(url, {filter: 'audioonly', quality:'highestaudio'});

        ytdl.getInfo(url).then(info => {
            titolo = info.videoDetails.title;

            res.header("Content-Disposition", 'attachment;  filename=' + titolo + '.mp4');

            const ffmpegProcess = cp.spawn(ffmpeg, [
                '-i', `pipe:3`,
                '-i', `pipe:4`,
                '-map','0:v:0',
                '-map','1:a:0',
                '-c:v', 'copy',
                '-c:a', 'aac',
                '-crf','27',
                '-preset','veryfast',
                '-movflags','frag_keyframe+empty_moov',
                '-f','mp4',
                '-loglevel','error',
                '-'
            ], {
                stdio: [
                'pipe', 'pipe', 'pipe', 'pipe', 'pipe',
                ],
            });
              
            aud.pipe(ffmpegProcess.stdio[4]);
            vid.pipe(ffmpegProcess.stdio[3]);
            ffmpegProcess.stdio[1].pipe(res);
        });
    }
    catch(err) {
        console.log("Error with URL: " + url + "\nERROR: " + err + "\n\n");
    }
});


  


  I have not found alternatives to do this. I need a working script to download youtube videos with good quality.

  


• Is there a way to batch save video information (frame height, width, rate, etc) to video files' metadata ? [closed]

  6 avril 2021, par André Levy

  Searched all over to no avail. I had a vague recollection that MediaInfo did it, but no can do. Perhaps there's a way with ffmpeg, but all I've seen are commands to export the metadata already on the files.