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Changing FocusMode not working using MediaStream API in Google Chrome

In Google Chrome Browser i was able to get live feed of my connected USB Camera using getUserMedia() API. I have a slider to change the brightness value and this is working fine. I also want focusMode to toggle from continuous to manual(The camera always starts with continuous focusMode).
I have the below Javascript code to change FocusMode.
const video_constraints ={};
//Create the following keys for Constraint
video_constraints.video = {};
video_constraints.video.width = {};
video_constraints.video.width.exact = 1920; //set video width
video_constraints.video.height = {};
video_constraints.video.height.exact = 1080; //set video height
video_constraints.video.frameRate = {};
video_constraints.video.frameRate.exact = 60; //set video frame rate
//Start stream
navigator.mediaDevices.getUserMedia(video_constraints).then(handleStreamSuccessCb).catch(handleStreamErrorCb);
function handleStreamSuccessCb()
{
console.log("Got Stream");
window.stream = stream;
videoElement.srcObject = stream;
getVideoCaps(stream);
}
function getVideoCaps(stream)
{
var videoTrackArray = stream.getVideoTracks();
var videoTrack = null;
for (i=0; i<videoTrackArray.length; i++)
{
if (videoTrackArray[i].kind == "video")
{
console.log("Video track found");
videoTrack = videoTrackArray[i];
break;
}
}
if (videoTrack != null)
{
setTimeout(() => {
const capabilities = videoTrack.getCapabilities()
console.log("Caps:");
console.log(capabilities);
//Brightness:
if (capabilities.brightness)
{
//configure slider settings
brightnessSliderUI.min = capabilities.brightness.min;
brightnessSliderUI.max = capabilities.brightness.max;
brightnessSliderUI.step = capabilities.brightness.step;
brightnessSliderUI.value = videoTrack.getSettings().brightness;
//set inital value
brightnessSliderValueUI.value = brightnessSliderUI.value;
//slider change listener
brightnessSliderUI.oninput = function() {
brightnessSliderValueUI.value = brightnessSliderUI.value;
videoTrack.applyConstraints({advanced : [{brightness: brightnessSliderUI.value}] });
}
}
else
{
console.log("brightnessNot supported");
}
//Focus Mode
if (capabilities.focusMode)
{
console.log(videoTrack.getSettings());// By default continuous value is set for focusMode
focusButtonUI.onclick = function(){
console.log("focusButton Clicked");
videoTrack.applyConstraints({advanced : [{focusMode: "manual"}]});
// I am not able to set focusMode to manual with the above statement
console.log(videoTrack.getSettings());
}
}
}, 500);
}
else
{
showErrorDialog("No Video track found in the stream");
}
}
With the below line i am trying to toggle the focusMode:
videoTrack.applyConstraints({advanced : [{focusMode: "manual"}]});
But this focus was still in continuous mode.
Can somebody tell what's wrong with the above code ?
Is it possible to toggle focusMode when Preview is live ?

Why does my second audio file not play using the currentTime property?

I would like my audio2 file to play when audio1.currentTime is 3 seconds, but I'm not able to make it work. I'm a newbie in javascript, what am I missing?. This is my current javascript code:
function initAudioPlayer(){
var audio1, audio2, ext, agent;
ext = ".mp3";
agent = navigator.userAgent.toLocaleLowerCase();
if(agent.indexOf('firefox') != -1 || agent.indexOf('opera') != -1) { ext = ".ogg";}
//Audio Objects: audio1 and audio2
audio1 = new Audio();
audio1.src = "folder/Audio1"+ext;
audio1.loop = false;
audio1.play();
audio2 = new Audio();
audio2.src = "folder/Audio2"+ext;
audio2.loop = false;
audio2.play();
//Function that reproduces the second audio file at second 3 of the first audio file
function audio2(){
if(audio1.currentTime == 3) {audio2.play();}
};
}
window.addEventListener("load", initAudioPlayer);

You Must use Audio Api and fetch buffers of your files.
Then you must plus each byte and copy to another new buffer.
this code can help you:
let idnex=0;
samples.forEach(buufer => {
if (index === 0) {
tempBuf = buufer;
} else {
tempBuf = this.appendBuffer(tempBuf, buufer);
}
index++;
});
and by thi method you can append two buffer:
private appendBuffer(buffer1, buffer2) {
const numberOfChannels = Math.min(buffer1.numberOfChannels, buffer2.numberOfChannels);
const tmp = this.audioContextService.createBuffer(Math.max(buffer1.numberOfChannels, buffer2.numberOfChannels),
Math.max(buffer1.length, buffer2.length), buffer1.sampleRate);
for (let i = 0; i < numberOfChannels; i++) {
const channel = tmp.getChannelData(i);
let finallArray = [];
let d = [];
const chanelTemp = buffer1.getChannelData(i);
if (buffer2.numberOfChannels <= i) {
finallArray = chanelTemp;
} else {
const c = buffer2.getChannelData(i);
if (chanelTemp.length > c.length) {
finallArray = chanelTemp;
d = c;
} else {
finallArray = c;
d = chanelTemp;
}
for (let j = 0; j < d.length; j++) {
finallArray[j] += d[j] / 2;
}
}
channel.set(finallArray, i);
}
you can see my demo here
Also You Can See this Answer

If you truly want this to be accurate in time, you can't use Audio() - that's the HTML5 <audio> element, which is not sample-accurate. Javascript is also not accurate enough in event delivery to use a callback to do this (to be fair, neither are most general-purpose native OS APIs). You need to schedule the playback in advance, which is where Web Audio (https://developer.mozilla.org/en-US/docs/Web/API/Web_Audio_API) comes in. You need to load both samples, decode them into AudioBuffers, and then schedule playing back each of them with an AudioBufferSourceNode.

JavaScript Audio Input

I am Vanessa and I am working with a Team on a project for university. We are working with JavaScript and we try to measure a huge micro deflection.
Our goal is to push off particles from the center of the canvas when hands are clapped. We just want to know how to convert the micro deflection to a number.
Thank´s a lot!
Vanessa

here is come code I wrote using Web Audio API which listens to the microphone and makes available both the time domain as well as frequency domain representation of the mic audio curve
<html><head><meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>capture microphone then show time & frequency domain output</title>
<script type="text/javascript">
var webaudio_tooling_obj = function () {
var audioContext = new AudioContext();
console.log("audio is starting up ...");
var BUFF_SIZE_RENDERER = 16384;
var audioInput = null,
microphone_stream = null,
gain_node = null,
script_processor_node = null,
script_processor_analysis_node = null,
analyser_node = null;
if (!navigator.getUserMedia)
navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia ||
navigator.mozGetUserMedia || navigator.msGetUserMedia;
if (navigator.getUserMedia){
navigator.getUserMedia({audio:true},
function(stream) {
start_microphone(stream);
},
function(e) {
alert('Error capturing audio.');
}
);
} else { alert('getUserMedia not supported in this browser.'); }
// ---
function show_some_data(given_typed_array, num_row_to_display, label) {
var size_buffer = given_typed_array.length;
var index = 0;
console.log("__________ " + label);
if (label === "time") {
for (; index < num_row_to_display && index < size_buffer; index += 1) {
var curr_value_time = (given_typed_array[index] / 128) - 1.0;
console.log(curr_value_time);
}
} else if (label === "frequency") {
for (; index < num_row_to_display && index < size_buffer; index += 1) {
console.log(given_typed_array[index]);
}
} else {
throw new Error("ERROR - must pass time or frequency");
}
}
function process_microphone_buffer(event) {
var i, N, inp, microphone_output_buffer;
microphone_output_buffer = event.inputBuffer.getChannelData(0); // just mono - 1 channel for now
}
function start_microphone(stream){
gain_node = audioContext.createGain();
gain_node.connect( audioContext.destination );
microphone_stream = audioContext.createMediaStreamSource(stream);
microphone_stream.connect(gain_node);
script_processor_node = audioContext.createScriptProcessor(BUFF_SIZE_RENDERER, 1, 1);
script_processor_node.onaudioprocess = process_microphone_buffer;
microphone_stream.connect(script_processor_node);
// --- enable volume control for output speakers
document.getElementById('volume').addEventListener('change', function() {
var curr_volume = this.value;
gain_node.gain.value = curr_volume;
console.log("curr_volume ", curr_volume);
});
// --- setup FFT
script_processor_analysis_node = audioContext.createScriptProcessor(2048, 1, 1);
script_processor_analysis_node.connect(gain_node);
analyser_node = audioContext.createAnalyser();
analyser_node.smoothingTimeConstant = 0;
analyser_node.fftSize = 2048;
microphone_stream.connect(analyser_node);
analyser_node.connect(script_processor_analysis_node);
var buffer_length = analyser_node.frequencyBinCount;
var array_freq_domain = new Uint8Array(buffer_length);
var array_time_domain = new Uint8Array(buffer_length);
console.log("buffer_length " + buffer_length);
script_processor_analysis_node.onaudioprocess = function() {
// get the average for the first channel
analyser_node.getByteFrequencyData(array_freq_domain);
analyser_node.getByteTimeDomainData(array_time_domain);
// draw the spectrogram
if (microphone_stream.playbackState == microphone_stream.PLAYING_STATE) {
show_some_data(array_freq_domain, 5, "frequency");
show_some_data(array_time_domain, 5, "time"); // store this to record to aggregate buffer/file
}
};
}
}(); // webaudio_tooling_obj = function()
</script>
</head>
<body>
<p>Volume</p>
<input id="volume" type="range" min="0" max="1" step="0.1" value="0.5"/>
</body>
</html>
just save this file and paste its file location into the browser ... you will get a prompt to acknowledge use of microphone ... to access audio data just see where I print snippets of it to javascript console ... so next step would be to write code to view the audio curve and take actions to move canvas objects

Is it possible to post process HTML5 video elements audio output with Web Audio Api?

I have an html5 video element and I need to apply different processing realtime on the video's output audio. On desktop I made it work with the WebAudio API. The Api is seemingly present on iOS also. I am able to inspect the created objects, but it doesn't modify the video's output signal.
Here's my example code:
$(function () {
window.AudioContext = window.AudioContext||window.webkitAudioContext;
var audioContext = new AudioContext();
var bufferSize = 1024;
var selectedChannel = 0;
var effect = (function() {
var node = audioContext.createScriptProcessor(bufferSize, 2, 2);
node.addEventListener('audioprocess', function(e) {
var input = e.inputBuffer.getChannelData(selectedChannel);
var outputL = e.outputBuffer.getChannelData(0);
var outputR = e.outputBuffer.getChannelData(1);
for (var i = 0; i < bufferSize; i++) {
outputL[i] = selectedChannel==0? input[i] : 0.0;
outputR[i] = selectedChannel==1? input[i] : 0.0;
}
});
return node;
})();
var streamAttached = false;
function attachStream(video) {
if (streamAttached) {
return;
}
var source = audioContext.createMediaElementSource(video);
source.connect(effect);
effect.connect(audioContext.destination);
streamAttached = true;
}
function iOS_video_touch_start() {
var video = $('#vid')[0];
video.play();
attachStream(video);
}
var needtouch = false;
$('#vid').on('play', function () {
attachStream(this);
}).on('loadedmetadata', function () {
this.play();
this.volume=1.0;
if (this && this.paused) {
if (needtouch == false) {
needtouch = true;
this.addEventListener("touchstart", iOS_video_touch_start, true);
}
}
});
window.panToRight = function(){
selectedChannel = 1;
};
window.panToLeft = function(){
selectedChannel = 0;
};
});
You can also check it on CP:
http://codepen.io/anon/pen/pgeJQG
With the buttons you are able to toggle between the left and the right channels. On desktop browsers (Chrome, Firefox, Safari tested) it works fine.
I have also tried the older createJavaScriptNode() instead of createScriptProcessor(). I have also tried it with an alternative effect chain, which was looking like this:
var audioContext = new (window.AudioContext||window.webkitAudioContext)();
audioContext.createGain = audioContext.createGain||audioContext.createGainNode;
var gainL = audioContext.createGain();
var gainR = audioContext.createGain();
gainL.gain.value = 1;
gainR.gain.value = 1;
var merger = audioContext.createChannelMerger(2);
var splitter = audioContext.createChannelSplitter(2);
//Connect to source
source = audioContext.createMediaElementSource(video);
//Connect the source to the splitter
source.connect(splitter, 0, 0);
//Connect splitter' outputs to each Gain Nodes
splitter.connect(gainL, 0);
splitter.connect(gainR, 1);
//Connect Left and Right Nodes to the Merger Node inputs
//Assuming stereo as initial status
gainL.connect(merger, 0, 0);
gainL.connect(merger, 0, 1);
//Connect Merger output to context destination
merger.connect(audioContext.destination, 0, 0);
As you probably noticed this code was using the built in nodes only. But no luck.
So my questions are: Is this even possible on mobile? If it is, than what am I missing? If it is not, than any possible workaround? Thanks

With Chrome on Android, MediaElementSource is not currently routed to WebAudio. This is a known issue and is planned to be fixed eventually.

How to record audio from Audio Element using javascript

I am making an audio recorder using HTML5 and Javascript and do not want to include any third party API, I reached at my first step by creating an audio retriever and player using <audio> tag and navigator.webkitGetUserMedia Function which get audio from my microphone and play in through <audio> element but I am not able to get the audio data in an array at this point I don't know what to do which function to use.

simple just create a audio node, below is tweaked code from MattDiamond's RecorderJS:
function RecordAudio(stream, cfg){
var config = cfg || {};
var bufferLen = config.bufferLen || 4096;
var numChannels = config.numChannels || 2;
this.context = stream.context;
var recordBuffers = [];
var recording = false;
this.node = (this.context.createScriptProcessor ||
this.context.createJavaScriptNode).call(this.context,
bufferLen, numChannels, numChannels);
stream.connect(this.node);
this.node.connect(this.context.destination);
this.node.onaudioprocess = function(e){
if (!recording) return;
for (var i = 0; i < numChannels; i++){
if(!recordBuffers[i]) recordBuffers[i] = [];
recordBuffers[i].push.apply(recordBuffers[i], e.inputBuffer.getChannelData(i));
}
}
this.getData = function(){
var tmp = recordBuffers;
recordBuffers = [];
return tmp; // returns an array of array containing data from various channels
};
this.start() = function(){
recording = true;
};
this.stop() = function(){
recording = false;
};
}
example usage:
var recorder = new RecordAudio(userMedia);
recorder.start();
recorder.stop();
var recordedData = recorder.getData();