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• 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.

  


• 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.

  


• using pocketsphinx_continuous with a .wav file

  3 avril 2013, par user2242131

  I am attempting to write an application that will allow a user to speak a small set of commands from a remote system and have them executed on my server. Using pocketsphinx to parse the spoken text. When run locally with the microphone, pocketsphinx_continuous works perfectly no matter how I slur the words. But when importing the audio file and using ffmpeg to downsample the audio to a single channel, 16 bit PCM file, it will parse the first word without difficulty. Then it will skip everything else and treat it as . I am confident that the problem is in the file format and not in the pocketsphinx configuration.

  Using command line
  ffmpeg -y -i Sound\AddSheet.wav -ac 1 -f s16le -acodec pcm_s16le -ar 16k AddTmp.wav
  in a batch file.

  The bottom of the output I get is :

  INFO: fsg_search.c(1407): Start node ADD.0:5:47
  
  INFO: fsg_search.c(1407): Start node <sil>.0:2:49
  
  INFO: fsg_search.c(1446): End node <sil>.126:128:305 (-486)
  
  INFO: fsg_search.c(1662): lattice start node <s>.0 end node <sil>.126
  
  INFO: ps_lattice.c(1352): Normalizer P(O) = alpha(<sil>:126:305) = -175371
  
  INFO: ps_lattice.c(1390): Joint P(O,S) = -176076 P(S|O) = -705
  
  000000000: ADD USER
  
  </sil></sil></s></sil></sil>

  Which is not the audio in the file. The words spoken in the file are "ADD SPREADSHEET", which works perfectly from the same microphone without the intervening .wav file.

  I have tried increasing the audio volume and decreasing the background noise using sox :

  sox -v 3.0 Sound\%1 Sound\%1-loud.wav ffmpeg -i Sound\%1-loud.wav -vn -ss 00:00:00 -t 00:00:01 -y Sound\%1-noiseaud.wav 
  
  sox Sound\%1-noiseaud.wav -n noiseprof Sound\%1-noise.prof 
  
  sox Sound\%1 Sound\%1-clean.wav noisered sound\noise.prof 0.21 
  
  ffmpeg -y -i Sound\%1-clean.wav -ac 1 -f s16le -acodec pcm_s16le -ar 16k AddTmp.wav

  with no noticeable effect on the final results.

  If you look at the output you will notice that fsg_search.c has found ADD as the start node, then silence for the remainder. Please help on this.