SDP Strings for recieving two streams

Integration
1

I am sending two streams from same transport.And I want to receive two separate streams?I was working in the ethan 91 mediasoup record demo?Is there anything i want to change in the sdp strings and ffmpeg files.Please reply if you know the answer.
The SDP file:
const { getCodecInfoFromRtpParameters } = require(‘./utils’);

// File to create SDP text from mediasoup RTP Parameters
module.exports.createSdpText = (rtpParameters) => {
const { video, audio } = rtpParameters;

// Video codec info
const videoCodecInfo = getCodecInfoFromRtpParameters(‘video’, video.rtpParameters);

// Audio codec info
const audioCodecInfo = getCodecInfoFromRtpParameters(‘audio’, audio.rtpParameters);

return `v=0
o=- 0 0 IN IP4 127.0.0.1
s=FFmpeg
c=IN IP4 127.0.0.1
t=0 0
m=video ${video.remoteRtpPort} RTP/AVP ${videoCodecInfo.payloadType}
a=rtpmap:${videoCodecInfo.payloadType} ${videoCodecInfo.codecName}/${videoCodecInfo.clockRate}

a=sendonly
m=audio ${audio.remoteRtpPort} RTP/AVP ${audioCodecInfo.payloadType}
a=rtpmap:${audioCodecInfo.payloadType} ${audioCodecInfo.codecName}/${audioCodecInfo.clockRate}/${audioCodecInfo.channels}
a=sendonly
`;

};

THE ffmpeg file:
// Class to handle child process used for running FFmpeg

const child_process = require(‘child_process’);
const { EventEmitter } = require(‘events’);

const { createSdpText } = require(‘./sdp’);
const { convertStringToStream } = require(‘./utils’);

const RECORD_FILE_LOCATION_PATH = process.env.RECORD_FILE_LOCATION_PATH || ‘./files’;

module.exports = class FFmpeg {
constructor (rtpParameters) {
this._rtpParameters = rtpParameters;
this._process = undefined;
this._observer = new EventEmitter();
this._createProcess();
}

_createProcess () {
const sdpString = createSdpText(this._rtpParameters);
const sdpStream = convertStringToStream(sdpString);

console.log('createProcess() [sdpString:%s]', sdpString);

this._process = child_process.spawn('ffmpeg', this._commandArgs);

if (this._process.stderr) {
  this._process.stderr.setEncoding('utf-8');

  this._process.stderr.on('data', data =>
    console.log('ffmpeg::process::data [data:%o]', data)
  );
}

if (this._process.stdout) {
  this._process.stdout.setEncoding('utf-8');

  this._process.stdout.on('data', data => 
    console.log('ffmpeg::process::data [data:%o]', data)
  );
}

this._process.on('message', message =>
  console.log('ffmpeg::process::message [message:%o]', message)
);

this._process.on('error', error =>
  console.error('ffmpeg::process::error [error:%o]', error)
);

this._process.once('close', () => {
  console.log('ffmpeg::process::close');
  this._observer.emit('process-close');
});

sdpStream.on('error', error =>
  console.error('sdpStream::error [error:%o]', error)
);

// Pipe sdp stream to the ffmpeg process
sdpStream.resume();
sdpStream.pipe(this._process.stdin);

}

kill () {
console.log(‘kill() [pid:%d]’, this._process.pid);
this._process.kill(‘SIGINT’);
}

get _commandArgs () {
let commandArgs = [
‘-loglevel’,
‘debug’,
‘-protocol_whitelist’,
‘pipe,udp,rtp’,
‘-fflags’,
‘+genpts’,
‘-f’,
‘sdp’,
‘-i’,
‘pipe:0’
];

commandArgs = commandArgs.concat(this._videoArgs);
commandArgs = commandArgs.concat(this._audioArgs);

commandArgs = commandArgs.concat([
  /*
  '-flags',
  '+global_header',
  */
  `${RECORD_FILE_LOCATION_PATH}/${this._rtpParameters.fileName}.webm`
]);

console.log('commandArgs:%o', commandArgs);

return commandArgs;

}

get _videoArgs () {
return [
‘-map’,
‘0:v:0’,
‘-c:v’,
‘copy’
];
}

get _audioArgs () {
return [
‘-map’,
‘0:a:0’,
‘-strict’, // libvorbis is experimental
‘-2’,
‘-c:a’,
‘copy’
];
}
}