HTML5 APIs - native multimedia support and beyond - University of Leeds 05.05.2011

HTML5 APIsNATIVE MULTIMEDIA SUPPORT AND BEYONDPatrick H. Lauke / University of Leeds / 5 May 2011

“...extending the language to better supportWeb applications [...] This puts HTML indirect competition with othertechnologies[...] , in particular Flash andSilverlight.”Ian Hickson, Editor of HTML5http://lists.w3.org/Archives/Public/public-html/2009Jan/0215.html

making your site Fonzie compliant...

<video>

Adobe Flash currently most common video delivery mechanism

<video src="video.webm" controls autoplay loop preload="none" poster="poster.jpg" width="320" height="240"> <a href="video.webm">Download movie</a></video>

video as native object● “plays nice” with rest of the page● keyboard accessibility built-in

video formats the big debate

MP4 / H.264ubiquitous, patent encumbered, licensing/royalties

Ogg Theora“free and open”, no licensing/royaltiesnot many tools for it, not web optimised

WebMopen and royalty-free, web optimised

www.youtube.com/html5

providing multiple sources<video controls autoplay poster="…" width="…" height="…"> <source src="movie.webm" type="video/webm" /> <source src="movie.ogv" type="video/ogg" /> <source src="movie.mp4" type="video/mp4" /> </video>

still include fallback for old browsers http://camendesign.com/code/video_for_everybody

powerful (simple) API to script your own controls

icant.co.uk/easy-youtube

www.w3.org/TR/html5/video.html#media-elements

controlling a <video> elementvar v = document.getElementById(player);v.play();v.pause();v.volume = … ;v.currentTime = … ;…

events fired by <video> elementvar v = document.getElementById(player);v.addEventListener(loadeddata, function() { … }, true)v.addEventListener(play, function() { … }, true)v.addEventListener(pause, function() { … }, true)v.addEventListener(timeupdate, function() { … }, true)v.addEventListener(ended, function() { … }, true)…

people.opera.com/patrickl/experiments/webm/basic-controls

people.opera.com/patrickl/experiments/webm/fancy-controls

people.opera.com/patrickl/experiments/webm/fancy-swap

<audio>

audio exactly the same as video<audio src=”music.mp3” controls autoplay></audio>[...]<audio controls autoplay> <source src="music.mp3" type="audio/mpeg" /> <source src="music.oga" type="audio/ogg" /> </audio>same format debacle: MP3 vs Ogg Vorbis (vs WAV)

canvas = “scriptable images”<canvas width="…" height="…"></canvas>

canvas has standard API methods for drawingctx = canvas.getContext("2d");ctx.fillRect(x, y, width, height);ctx.beginPath();ctx.moveTo(x, y);ctx.lineTo(x, y);ctx.bezierCurveTo(x1, y1, x2, y2, c1, c2);

people.opera.com/patrickl/experiments/canvas/particle/3

mariuswatz.com/works/abstract01js

www.benjoffe.com/code/demos/canvascape

canvas drawing ready-made imagesctx = canvas.getContext("2d");var logo = new Image();logo.src = logo.png;ctx.drawImage(logo,x1,y1,w1,h1,x2,y2,w2,h2);or call in an existing image already on the page

www.splintered.co.uk/experiments/archives/paranoid_0.3

canvas access to image data arrayctx = canvas.getContext("2d");canvasData = ctx.getImageData(x,y,w,h);[R,G,B,A,R,G,B,A,R,G,B,A,R,G,B,A, … ]

www.splintered.co.uk/experiments/archives/canvas-ambilight

github.com/mezzoblue/PaintbrushJS

canvas also works with videoctx = canvas.getContext("2d");v = document.getElementById(player);ctx.drawImage(v,x1,y1,w1,h2,x2,y2,w2,h2);grab currently displayed frame (update as appropriate)

html5doctor.com/video-canvas-magic

media.chikuyonok.ru/ambilight

www.filamentgroup.com/examples/charting

canvas accessibility concerns

video, audio and canvas on any device without plugins (Java / Flash / Silverlight not ubiquitous)

HTML5 (and friends) haslots more APIs for developers (for powerful client-side apps)

isgeolocationpartofhtml5.com

geolocationnavigator.geolocation.getCurrentPosition(success, error);navigator.geolocation.watchCurrentPosition(success, error);function success(position) { /* wheres Wally? */ var lat = position.coords.latitude; var long = position.coords.longitude; ...}

owlsnearyou.com

offline detectionwindow.addEventListener(online, function(){ … }, true);window.addEventListener(offline, function(){ … }, true); …however, currently unreliable!

application cache<html manifest=”blah.manifest”>CACHE MANIFEST# send this with correct text/cache-manifest MIMEimages/sprites.pngscripts/common.jsscripts/jquery.jsstyles/global.cssNETWORK:# never cached (apart from normal caching mechanism)onlineonly.cssFALLBACK:# pattern matching. fallback file will also be cachedimages/ images/not-offline.png

localStorage/sessionStoragelike cookies...document.cookie = key=value; expires=Thu, 15 Feb 201023:59:59 UTC; path=/…/* convoluted string operations go here … */

localStorage/sessionStoragelike cookies...on steroids!localStorage.setItem(key, value);localStorage.getItem(key);localStorage.clear();localStorage.key = value;if (localStorage.key == …) { … }…

WebSQLrelational DB / SQL in browservar db =openDatabase(dbName, version, displayName, expectedSize);db.transaction(function(tx) { tx.executeSql(sqlStatement, [], function (tx, result) { /* do something with the results */ });});not being developed further (IE/Mozilla prefer IndexedDB)– nonetheless available right now in Opera+WebKit!

is it all safe to use, right now?

dont do browser sniffing http://www.flickr.com/photos/timdorr/2096272747/

feature-detectionprogressive enhancement, graceful degradation – or use shims http://diveintohtml5.org/everything.html

feature-detection for audio/videoif (!!document.createElement(video).canPlayType;) { … }if (!!document.createElement(audio).canPlayType;) { … }

feature-detection for audio/video codecsvar v = document.createElement(video);if (!!(v.canPlayType)&& ((v.canPlayType(video/webm;codecs="vp8,vorbis") == probably) || (v.canPlayType(video/webm;codecs="vp8, vorbis") == maybe))){ … }

ready-made HTML5 audio/video players (for the lazy)

sublimevideo.net

videojs.com

www.happyworm.com/jquery/jplayer

HTML5 as Flashkiller?

not a question of HTML5 replacing Flash...

giving developers a choice!

www.opera.com/developer patrick.lauke@opera.com

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HTML5 APIs - native multimedia support and beyond - University of Leeds 05.05.2011

by Patrick Lauke

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