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fadespreview.js
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fadespreview.js
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var newsource;
function fadespreview(){
clearInterval(intervalid);
clearInterval(intervalid12);
clearInterval(videointerval)
var start = parseFloat(document.getElementById("start").value);
var end = parseFloat(document.getElementById("end").value);
var startgain = parseFloat(document.getElementById("gainstart").value)
var gainreach = parseFloat(document.getElementById("gainreach").value)
var gainselect = document.getElementById("gainselect").value;
time = parseInt(start);
var final = end - start;
if (sourcecheck === null){
if(source){
source.stop();
}
if(source1){
source1.stop();
}
}
if (check === null ){
document.getElementById("error").innerHTML = "Please select a file"
}
else if (bufferarray===null){
document.getElementById("error").innerHTML = "No data available"
}
else if (isNaN(start)){
document.getElementById("error").innerHTML = "Starting point is not a number"
}
else if (start >= source.buffer.duration){
document.getElementById("error").innerHTML = "starting point is greater than or equal to source buffer duration"
}
else if (start < 0 )
{
document.getElementById("error").innerHTML = "Starting Point must be greater than 0"
}
else if (start >= end) {
document.getElementById("error").innerHTML = "Starting Point must be less than Ending Point"
}
else if (isNaN(end)){
document.getElementById("error").innerHTML = "Ending Point is not a number"
}
else if ( end > source.buffer.duration ){
document.getElementById("error").innerHTML = "Ending point is greater than duration"
end < 0 }
else if ( end <= start){
document.getElementById("error").innerHTML = "Ending Point is greater than equal to Starting Point"
}
else{
const offlineCtx = new AudioContext();
var array1 = new Float32Array(end*bufferarray.sampleRate -start*bufferarray.sampleRate)
bufferarray.copyFromChannel(array1, 0, start*bufferarray.sampleRate)
var sourcebuffer = offlineCtx.createBuffer(bufferarray.numberOfChannels, array1.length, bufferarray.sampleRate);
var channeldata = sourcebuffer.getChannelData(0)
channeldata.set(array1)
source1 = offlineCtx.createBufferSource();
var gain = offlineCtx.createGain();
if(gainselect ==='set value at time'){
if (isNaN(startgain)){
}
else{
gain.gain.setValueAtTime(startgain, 0)
}
}
if(gainselect ==='linear ramp'){
if(isNaN(startgain)||isNaN(gainreach)){
}
else{
gain.gain.setValueAtTime(startgain, 0)
gain.gain.linearRampToValueAtTime(gainreach, array1.length/bufferarray.sampleRate)
}
}
if(gainselect ==='exponential ramp'){
if(isNaN(startgain) || isNaN(gainreach) || gainreach<=0){
}
else{
gain.gain.setValueAtTime(startgain, 0)
gain.gain.exponentialRampToValueAtTime(gainreach, array1.length/bufferarray.sampleRate)
}
}
source1.buffer = sourcebuffer;
source1.connect(gain)
gain.connect(offlineCtx.destination)
source1.start(0)
}}