Principal Web Developer at Freedom of the Press Foundation
Published
Edited
Mar 7, 2022
Meyda = require(`meyda@${version.substring(1)}`)
audioContext = 'AudioContext' in window ? new AudioContext() : new window.webkitAudioContext()
audioFile = {
const oscillator = audioContext.createOscillator()
oscillator.frequency.setValueAtTime(261.6, audioContext.currentTime)
const destination = audioContext.createMediaStreamDestination()
const mediaRecorder = new MediaRecorder(destination.stream)
oscillator.connect(destination)
const chunks = []
mediaRecorder.ondataavailable = (evt) => { chunks.push(evt.data) }
// Record
mediaRecorder.start(10)
oscillator.start(0)
// Stop recording after one second
await new Promise((resolve) => setTimeout(() => {
mediaRecorder.stop()
oscillator.stop(0)
resolve()
}, 1000))
return new Blob(chunks, { 'type' : 'audio/ogg; codecs=opus' });
}
blobUrl = URL.createObjectURL(audioFile)
html`<audio src="${blobUrl}" controls />`
audioBuffer = audioContext.decodeAudioData(await (await fetch(blobUrl)).arrayBuffer())
{
Meyda.chromaBands = 12
const chroma = Meyda.extract('chroma', audioBuffer.getChannelData(0).slice(0, 4096))
return arrayTable(chroma)
}
{
Meyda.chromaBands = 24
const chroma = Meyda.extract('chroma', audioBuffer.getChannelData(0).slice(0, 4096))
return arrayTable(chroma)
}
arrayTable = a => {
const tableRows = a.map(
(d, i) => `${d === 1 ? `**${i}**` : i} | ${d === 1 ? `**${d}**` : d}`
).join('\n')
return md`
index | value
---|---
${tableRows}
`
}
releases = (await fetch('https://api.github.com/repos/meyda/meyda/releases')).json()
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