alexcohn · May 9, 2018 18:32
diff --git a/qq.html b/qq.html
 <!DOCTYPE html>
 <html>

 <head>
    <meta charset="UTF-8">
    <title>Audio Recorder</title>
    <style>
        audio {
            display: block;
        }
    </style>
 </head>

 <body>

    <button type="button" onclick="mediaRecorder.start(1000)">Start</button>
    <button type="button" onclick="mediaRecorder.stop()">Stop</button>


    <script type="text/javascript">
        var mediaRecorder = null,
        audio = null,
        chunks = [],
        startTs = 0,
        timeout = null,
        max_duration = 4;// in seconds.

    function onSuccess( stream ) {
        mediaRecorder = new MediaRecorder( stream );
        mediaRecorder.ondataavailable = function( event ) {
            document.body.insertAdjacentHTML( 'beforeend', 'add chunk #' + chunks.length + ' at ' + (Date.now()-startTs) + ' '  + event.data.size + ' bytes <br/>' );
            chunks.push( event.data )
            if ( chunks.length >= max_duration && mediaRecorder.state === 'recording' ) {
                document.body.insertAdjacentHTML( 'beforeend', 'stop ' + (Date.now()-startTs) + '<br/>' )
                mediaRecorder.stop()
            }
        }

        mediaRecorder.onstart = function() {
            startTs = Date.now()
            document.body.insertAdjacentHTML( 'beforeend', '<br/>start <br/>' )

            setTimeout(function() {
                if ( mediaRecorder.state === 'recording' ) {
                    document.body.insertAdjacentHTML( 'beforeend', 'timeout ' + (Date.now()-startTs) + '<br/>' )
                    stream.getAudioTracks()[0].enabled = false
                }
            }, max_duration*1000)
        };

        mediaRecorder.onstop = function() {
            audio = document.createElement('audio')
            audio_blob = new Blob(chunks, {
                'type' : 'audio/mpeg'
            })
            audio.controls = 'controls'
            audio.autoplay = 'autoplay'
            audio.src = URL.createObjectURL( audio_blob )
            setTimeout(function() {
                if (audio.parent == null ) {
                    document.body.appendChild(audio)
                }
            }, 5000);
            startTs = Date.now()
            timeout = setInterval(function() {
                if (Number.isFinite(audio.duration)) {
                    document.body.insertAdjacentHTML( 'beforeend', '<br/>duration ' + audio.duration + ' calculated in ' + (Date.now()-startTs) + ' for ' + chunks.length + ' chunks <br/>' )
                    if ( Math.floor(audio.duration) > max_duration - 2 && audio.parent == null ) {
                        chunks = chunks.slice(0, chunks.length-1)
                        shorter_audio_blob = new Blob(chunks, {
                            'type' : 'audio/mpeg'
                        })
                        audio.src = URL.createObjectURL( shorter_audio_blob )
                    }
                    else {
                        clearInterval(timeout)
                        document.body.appendChild(audio);
                    }
                }
            }, 10) // it takes some time for duration to become valid
        }
    }

    var onError = function(err) {
        console.log('Error: ' + err)
    }

    navigator.mediaDevices.getUserMedia({ audio: true }).then(onSuccess, onError)
    </script>
 </body>
 </html>
	<!DOCTYPE html>
	<html>

	<head>
	<meta charset="UTF-8">
	<title>Audio Recorder</title>
	<style>
	audio {
	display: block;
	}
	</style>
	</head>

	<body>

	<button type="button" onclick="mediaRecorder.start(1000)">Start</button>
	<button type="button" onclick="mediaRecorder.stop()">Stop</button>


	<script type="text/javascript">
	var mediaRecorder = null,
	audio = null,
	chunks = [],
	startTs = 0,
	timeout = null,
	max_duration = 4;// in seconds.

	function onSuccess( stream ) {
	mediaRecorder = new MediaRecorder( stream );
	mediaRecorder.ondataavailable = function( event ) {
	document.body.insertAdjacentHTML( 'beforeend', 'add chunk #' + chunks.length + ' at ' + (Date.now()-startTs) + ' ' + event.data.size + ' bytes <br/>' );
	chunks.push( event.data )
	if ( chunks.length >= max_duration && mediaRecorder.state === 'recording' ) {
	document.body.insertAdjacentHTML( 'beforeend', 'stop ' + (Date.now()-startTs) + '<br/>' )
	mediaRecorder.stop()
	}
	}

	mediaRecorder.onstart = function() {
	startTs = Date.now()
	document.body.insertAdjacentHTML( 'beforeend', '<br/>start <br/>' )

	setTimeout(function() {
	if ( mediaRecorder.state === 'recording' ) {
	document.body.insertAdjacentHTML( 'beforeend', 'timeout ' + (Date.now()-startTs) + '<br/>' )
	stream.getAudioTracks()[0].enabled = false
	}
	}, max_duration*1000)
	};

	mediaRecorder.onstop = function() {
	audio = document.createElement('audio')
	audio_blob = new Blob(chunks, {
	'type' : 'audio/mpeg'
	})
	audio.controls = 'controls'
	audio.autoplay = 'autoplay'
	audio.src = URL.createObjectURL( audio_blob )
	setTimeout(function() {
	if (audio.parent == null ) {
	document.body.appendChild(audio)
	}
	}, 5000);
	startTs = Date.now()
	timeout = setInterval(function() {
	if (Number.isFinite(audio.duration)) {
	document.body.insertAdjacentHTML( 'beforeend', '<br/>duration ' + audio.duration + ' calculated in ' + (Date.now()-startTs) + ' for ' + chunks.length + ' chunks <br/>' )
	if ( Math.floor(audio.duration) > max_duration - 2 && audio.parent == null ) {
	chunks = chunks.slice(0, chunks.length-1)
	shorter_audio_blob = new Blob(chunks, {
	'type' : 'audio/mpeg'
	})
	audio.src = URL.createObjectURL( shorter_audio_blob )
	}
	else {
	clearInterval(timeout)
	document.body.appendChild(audio);
	}
	}
	}, 10) // it takes some time for duration to become valid
	}
	}

	var onError = function(err) {
	console.log('Error: ' + err)
	}

	navigator.mediaDevices.getUserMedia({ audio: true }).then(onSuccess, onError)
	</script>
	</body>
	</html>