34:null 35:["$","title",null,{"children":"Soundcloud Reactive Audio Visualizer Music Video Generator | ptvans | Observable"}] 3b:T5a3,md`# Soundcloud Reactive Audio Visualizer Music Video Generator This is a tool for generating video from any Soundcloud track. Scroll down to find customize the audio input URL and put whatever you like. Press record to generate a downloadable _webm_ for sharing. Or just chill out by going fullscreen. More options are scattered throughout the page (e.g. video resolution or customization of visuals). I hope it might help a few artists with video production. This app was developed to help me learn a few things before building a full audio visual mixing demoscene system. In particular, you can click under the hood, fork the code and create your own experiences. Its licensed as ISC so you can do what you like with the code and output, no need to credit me, though I would be honoured. This demos the following technologies 1. Using the Web Audio API to extract a waveform to drive reactive visuals 1. Using Three.js effects composer to create multi layed visuals with post processing effects 1. Importing audio from external sources (Soundcloud) 1. Setting up an high performance Web Audio API graph. 1. Extracting a combined audio and visual into a single video file. 1. Using the wake lock API to prevent the host sleeping when fullscreened. 1. Inserting HTML into a Three.js scene. These are foundational techniques for doing even cooler things in the browser! Stay tuned! Use the comment feature to get in touch. ` 3c:T941,{ var controls = null; const rewind = () => { stop() source.mediaElement.currentTime = 0; } const play = () => { console.log("play") context.resume() source.connect(analyser); analyser.connect(context.destination); source.mediaElement.play(); } const stop = () => { console.log("stop") source.mediaElement.pause(); } const fullscreen = async (event) => { controls.parentElement.nextElementSibling.requestFullscreen(); await navigator.wakeLock.request('screen'); } const record = async (event) => { document.getElementById("downloadlink").innerHTML = "" var recordedChunks = []; return new Promise(function (res, rej) { const canvas = document.getElementById("visualizer"); const video = canvas.captureStream(); const audio = context.createMediaStreamDestination(); analyser.connect(audio) const stream = new MediaStream([video.getVideoTracks()[0], audio.stream.getAudioTracks()[0]]) const mediaRecorder = new MediaRecorder(stream, { mimeType: "video/webm; codecs=vp9" }); mediaRecorder.start(); play() function stopRecorder() { mediaRecorder.stop(); source.mediaElement.removeEventListener("pause", stopRecorder, true); source.mediaElement.removeEventListener('ended', stopRecorder, true); } source.mediaElement.addEventListener("pause", stopRecorder, true); source.mediaElement.addEventListener('ended', stopRecorder, true); mediaRecorder.ondataavailable = function (event) { console.log("Chunk recorded", event) recordedChunks.push(event.data); } mediaRecorder.onstop = function (event) { console.log("stopped") var blob = new Blob(recordedChunks, { type: "video/webm" }); var url = URL.createObjectURL(blob); const downloadLink = document.getElementById("downloadlink") downloadLink.href = url downloadLink.innerHTML = "download" } }) } controls = html` ` return controls; } 3d:T80f,{ const width = resolution.width; const height = resolution.height; var camera = new THREE.OrthographicCamera(width / -2, width / 2, height / 2, height / -2, 0, height / -2); const renderer = new THREE.WebGLRenderer(); const renderTarget = new THREE.WebGLRenderTarget( width, height, { depthBuffer: false }); renderer.setClearColor(new THREE.Color(0x000000, 1.0)); renderer.domElement.id = "visualizer" invalidation.then(() => renderer.dispose()); renderer.setSize(width, height); const composer = new EffectComposer( renderer, renderTarget); const scene = new THREE.Scene(); scene.background = new THREE.Color(0x000000); scene.add(buffers.line); const renderScene = new RenderPass( scene, camera ); const bloomPass = new UnrealBloomPass( new THREE.Vector2( width, height), 1.5, 0.4, 0.85 ); bloomPass.threshold = 0; bloomPass.strength = 7; bloomPass.radius = 1; composer.addPass( renderScene ); composer.addPass( bloomPass ); { // Credits const texture = new THREE.TextureLoader().load(title.img); texture.needsUpdate = true; var material = new THREE.MeshBasicMaterial({ map: texture, side: THREE.DoubleSide, transparent: true }); const geometry = new THREE.PlaneBufferGeometry(title.width, title.height); const mesh = new THREE.Mesh( geometry, material ); mesh.position.set( width/2.0 - title.width/2.0, - height/2.0 + title.height / 2.0, 0) const titleScene = new THREE.Scene(); titleScene.add(mesh); const renderTitle = new RenderPass( titleScene, camera); renderTitle.clear = false; composer.addPass( renderTitle ); const copyPass = new ShaderPass( CopyShader ); copyPass.renderToScreen = true; composer.addPass( copyPass ); } const t_start = performance.now(); while (true) { mutable t = performance.now() - t_start composer.render(); yield renderer.domElement; } }3e:T67e,viewof source = render(({ useSetter }) => { const [searchInput, setSearchInput] = useState( decodeURIComponent((location.hash || '#https://soundcloud.com/avand/home-smoke-home').substring(1)) ); const [search, setSearch] = useState(searchInput); const [track, setTrack] = useState(null); const [media, setMedia] = useState(null) useEffect(() => { SC.resolve(search).then(track => setTrack(track)).catch(e => setTrack(null)) }, [search]); useEffect(() => { if (track === null) { setMedia(null); } else { const audio = new Audio() audio.crossOrigin = "anonymous"; audio.src = track.stream_url + "?client_id=" + SC.client_id; setMedia(context.createMediaElementSource(audio)) } }, [track]); useEffect(() => { // change the top url if (media !== null) document.getElementById("audioviz").click() }, [media]); const view = media || {} view.search = search; view.track = track; useSetter(view); return jsx` setSearchInput(e.target.value)} onKeyDown=${e => e.key === 'Enter' && setSearch(searchInput)} /> ${track && jsx`

`} `; })3f:T649,draw = { t // force this cell to update when time increments if (source.mediaElement.paused) return; const width = resolution.width; const height = resolution.height; const points = []; const colors = []; const point = new THREE.Vector3(); const color = new THREE.Color(); // Rotating colors color.setRGB(Math.cos(t * 0.00011) * 0.5 + 1, Math.cos(t * 0.002) * 0.5 + 1, Math.cos(t * 0.003) * 0.5 + 1) // Positions driven by audio analyser analyser.getByteTimeDomainData(buffers.dataArray); for (let i = 0; i < buffers.dataArray.length; i++) { var mod = 1; // Math.sin(i * Math.PI / buffers.dataArray.length) var y = ((buffers.dataArray[i] * height / 256.0) - (height/2.0)) * mod; var x = -width/2 + i * width / buffers.dataArray.length; points.push(x, y, 0); colors.push(color.r, color.g, color.b); } // loop wave form round to enter the view from the left again points.push(width*2, 0, 0); points.push(width*2, height*2, 0); points.push(-width*2, height*2, 0); points.push(-width*2, 0, 0); // The main stratergy is to shift all the buffers down, and append new data points to the end buffers.positions.set(buffers.positions.array.slice(points.length)); buffers.positions.set(points, buffers.positions.count * 3 - points.length); buffers.positions.needsUpdate = true; // Decay the colors by a factor so the old lines fade out buffers.colors.set(buffers.colors.array.slice(colors.length).map(x => x * 0.5), 0); buffers.colors.set(colors, buffers.colors.count * 3 - colors.length); buffers.colors.needsUpdate = true; }40:[{"id":"0ca7672d7694da0962dad33a84de2e6e0c9199f8d7251a26795f167fcfaebcb672849b35f1399140cf878a9fe42160a4f709746e976f02c730f4f49901f94b7d","href":"https://static.observableusercontent.com/files/0ca7672d7694da0962dad33a84de2e6e0c9199f8d7251a26795f167fcfaebcb672849b35f1399140cf878a9fe42160a4f709746e976f02c730f4f49901f94b7d","name":"colors.json","type":"application/json","lastModified":1601954630012.372,"size":232449},{"id":"987350cd53fddf223d46539654cd6e07de3a5d182eca513c0bac27d18f25547cc61073dae7e52d9f06ca045fda5e0867fae249441dd892802f27a91673a67bfe","href":"https://static.observableusercontent.com/files/987350cd53fddf223d46539654cd6e07de3a5d182eca513c0bac27d18f25547cc61073dae7e52d9f06ca045fda5e0867fae249441dd892802f27a91673a67bfe","name":"positions.json","type":"application/json","lastModified":1601954630012.372,"size":105942}] 39:{"id":"735e250accef26e8","slug":"soundcloud-reactive-audio-visualizer-music-video-generat","title":"Soundcloud Reactive Audio Visualizer Music Video Generator","thumbnail":"db276095ffaab4fcd75d4ae41d10bb1102c01c261eb231cf04df980c17182d80","access_level":"public","create_time":"$D2020-10-06T03:23:50.012Z","update_time":"$D2020-10-06T03:33:38.948Z","view_time":null,"first_public_time":"$D2020-10-06T03:32:43.792Z","has_unpublished_edits":null,"fork":{"id":"75ca9de6c8daba14","slug":"sound-cloud-reactive-audio-visualizer","title":"Soundcloud Reactive Audio Visualizer Music Video Generator","owner":{"id":"7db5ed2b0697d645","login":"tomlarkworthy","name":"Tom Larkworthy"}},"stars":1,"starred":false,"owner":{"type":"team","id":"b6a977fcae8c7e2e","login":"ptvans","name":"","avatar_url":"https://avatars-next.observableusercontent.com/7e463c1310accf34a64a7d4dc23ba9485c3b1c67155d59d7f6882b8b9f76bf7a","tier":"starter_2024","bio":"","following":false},"version":1184,"publish_version":1184,"role":null,"authored":false,"authors":[{"type":"individual","id":"230b51e3ce71e786","login":"ptvans","name":"","avatar_url":"https://avatars-next.observableusercontent.com/7e463c1310accf34a64a7d4dc23ba9485c3b1c67155d59d7f6882b8b9f76bf7a","tier":null,"bio":"","following":false}],"members":[{"type":"individual","id":"230b51e3ce71e786","login":"ptvans","name":"","avatar_url":"https://avatars-next.observableusercontent.com/7e463c1310accf34a64a7d4dc23ba9485c3b1c67155d59d7f6882b8b9f76bf7a","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":4,"collection":null,"type":"notebook","body":{"titling":"auto","title":"Soundcloud Reactive Audio Visualizer Music Video Generator","cells":[{"id":0,"value":"$3b","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":79,"value":"$3c","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":183,"value":"$3d","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1140,"value":"resolution = JSON.parse(resolution_str)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":1115,"value":"viewof resolution_str = select([\n {label: `screen (${width}, ${height})`, value: JSON.stringify({width:width, height:height})},\n {label: \"1080p (1920x1080)\", value: JSON.stringify({width:1920, height:1080})},\n ]);","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":480,"value":"md`Create a global Audio Context`","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":152,"value":"context = new AudioContext()","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","tool":"$undefined","providerMetadata":"$undefined","attachments":"$undefined","output":"$undefined","database":"$undefined"},{"id":491,"value":"md`Create an Media Element Source. 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