A reliable Class which will convert mjr to wav for janus without any errors

JanusMjrConverter.js

const { spawn } = require('child_process');
const path = require('path');
const fs = require('fs');

class JanusMjrConverter {
  constructor(inputDir, mjrFilename, wavFilename) {
    this.inputDir = path.resolve(inputDir);
    this.mjrPath = path.join(this.inputDir, mjrFilename);
    this.wavPath = path.join(this.inputDir, wavFilename);
    this.totalCount = 0;
  }

  runJanusCommand(args) {
    return new Promise((resolve, reject) => {
      const process = spawn('janus-pp-rec', args);
      let output = '';

      process.stdout.on('data', data => {
        output += data.toString();
      });

      process.stderr.on('data', data => {
        output += data.toString(); // Capture stderr as well (like Bash 2>&1)
      });

      process.on('close', code => {
        resolve(output);
      });

      process.on('error', err => {
        reject(err);
      });
    });
  }

  errorRtpPackets(output) {
    return (output.match(/Late pre-reset packet: \d+/g) || []).length;
  }

  extractRtpPacketCount(output) {
    const match = output.match(/Counted (\d+) frame packets/);
    return match ? parseInt(match[1], 10) : 0;
  }

  async getIgnoreCount() {
    const args = ['-p', this.mjrPath];
    const parsedOutput = await this.runJanusCommand(args);

    const errorCount = this.errorRtpPackets(parsedOutput);
    this.totalCount = this.extractRtpPacketCount(parsedOutput);
    return this.totalCount - errorCount;
  }

  async convert() {
    try {
      const ignoreCount = await this.getIgnoreCount();
      const args = [
        '-i', ignoreCount.toString(),
        '--restamp=2000',
        '--restamp-packets=20',
        '--restamp-min-th=300',
        '--silence-distance=50',
        '--audioskew=500',
        this.mjrPath,
        this.wavPath
      ];

      const output = await this.runJanusCommand(args);
      if (!output.includes('Writing .wav')) {
        console.warn('Invalid MJR file, skipping:', path.basename(this.mjrPath));
        console.log(output);
      } else {
        console.log(output);
        console.log(`Total packets: ${this.totalCount}`);
      }
    } catch (err) {
      console.error('Conversion failed:', err.message);
    }
  }
}

// Example usage:
const converter = new JanusMjrConverter(
  './input',
  '435c9111d65d49192bec20202bfb0060-peer-audio.mjr',
  '435c9111d65d49192bec20202bfb0060-peer-audio.wav'
);

converter.convert();