HTML5 Audio APIs – How Low can we Go?

By Mark Boas

“O ye’ll tak’ the high road, and Ah’ll tak’ the low (road)
And Ah’ll be in Scotlan’ afore ye.”
(The Bonnie Banks o’ Loch Lomond)

The web audio community are a vibrant bunch. No sooner had the standard <audio> API been established, than developers were clamouring for more. Just playing audio wasn’t enough, we wanted to analyse, react to and manipulate our audio. Happily, the browser makers obliged with first Mozilla, then Google producing enhanced web audio APIs for their browsers – the only problem was, they were two very different implementations. The Audio Data API implemented in Firefox exposed the data at a fairly low level, while Webkit’s Web Audio API provided a higher level abstraction providing a number of predefined functions. Luckily, it didn’t take long for the JavaScript community to react and start bridging the gap between the two, by writing libraries that provided a common API, libraries such as sink.js which smooths over low level differences. In turn, sink.js was used by ‘higher level’ libraries like audiolib.js – (a general purpose audio toolkit) and Audiolet (which provides a more musically intuitive API, with similar objectives to Webkit’s in-browser solution). There are many others, such as XAudioJS which sports a Flash® and base64 data url wav generation fallback, older projects like dynamic.js that just provides a Flash® fallback for the Audio Data API and DSP.js a Digital Signal Processing Library.

People really love messing about with audio.

Notice that the process of creating all this cool functionality didn’t come about from a W3C spec. Similarly, the Advanced Audio APIs were not the result of a W3C think-tank, but from two competing visions of what an advanced audio API should look like. Now it looks like the Web Audio API will be implemented in Safari as well as Chrome.

Once you create compelling functionality, developers will immediately start to use it. It may be experimental but developers will start to rely on it to make cool stuff. Cutting edge technology is seductive like that. I’m surer than sure that the Web Audio API has been well researched and has taken much inspiration from tried and tested APIs that exist outwith of our lovely browser based world (Apple’s Core Audio Frameworks, I believe), but I’m not convinced that you can really tell what web developers need or want until you give them something to play with.

Mozilla’s approach was to expose a very comprehensive low level API, which potentially allows JavaScript developers to create all the functionality of Webkit’s Web Audio API and then some. As a result we get libraries like JSMad cropping up. What does JSMad do? Significantly, it allows you to play MP3s in Firefox*. Is JavaScript fast enough? Apparently so. This was a ‘this changes everything’ moment for me and since then a similar approach has been taken by pdf.js and more recently Broadway.js which decodes H.264 on the fly.

*Neither Firefox or Opera support MP3 natively due to patent concerns.

I’m not saying Mozilla’s Audio Data API is perfect, there are issues with audio using the same thread as the UI and synch issues with multiple streams. However this is being addressed in the MediaStreams Processing proposal and it’s worth taking a look at it, even if it’s just for an insight into what future implementations could look like.

I’m digressing. The point is, if browser makers expose the low level API, developers will quickly come in and start writing libraries on top of that API. As is often the case, the developer community will start making things that the browser makers had never even considered. It makes sense, there are many more web developers than browser developers. Sure, web developers will bridge the gaps and polyfill over the cracks, which let’s face it, has been the only reasonable way of going forward with HTML5, but crucially they will also make new libraries that other developers can use – and all of this at very high rates of turnaround. Of course, the common-or-garden JavaScript developer has a series of enormous advantages over the browser API developer or the standards bodies that seek to define these APIs. I’m gonna name three here:

  1. Strong community — Web developers have a huge active and open community to draw from.

  2. Lower barrier to entry — The barrier of participation once something is put on something like github is virtually zero.

  3. Room to manouevre — Nothing web developers write is ever set in stone, JavaScript represents a much more fluid abstraction than the less flexible native browser code.

Ok, so bear with me here, and this is more of a question than a proposal – What if we separate concerns between browser makers and web developers when it comes to creating standards? Browser makers could concentrate on security, privacy, performance and exposing low level API’s in such a way that web developers can start to build libraries and APIs in the fluid, dynamic, iterative and extremely reactive manner that the web as a media allows. Once these libraries reach an acceptable level of adoption, browser makers can get together and decide which of these features they want to adopt based on tried and tested use cases, and yes make it a standard and build it into the browser. Wouldn’t we move forward more quickly that way? And as a bonus, no browser would be left behind as we’d be building the polyfills along the way.

In short, what I’m saying is that if the standard bodies put their energy into defining low level APIs, the high level APIs will look after themselves, or rather the community will look after them. After all it seems that the W3C themselves want a more community based approach to standards and besides we all know that bottom-up trumps top-down, right?

Outside my flat is an open space that the local council didn’t quite know what to do with, I’m sure they considered adding basket-ball hoops, concrete tables, a kid’s playground and all kinds of things. As it turned out they created a decent flat surface and pretty much left it as that. The users of this space, mostly children, decided this was a perfect space for playing soccer and improvised the space to include a hand drawn goal and pitch markings. If the council really wanted to make something permanent, they could take inspiration from this and create real goals and solid pitch markings.

It’s probably too late to change the Webkit implementation of the Web Audio API significantly, but I would strongly urge the developers of it to include a more comprehensive low level API in future releases. What’s the worst that could happen?

Improvised Goal Posts

A big thanks to Jussi Kalliokoski and Dustin Blake for helping with this post and deep respect and gratitude to all those hacking on audio.

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Tuesday, November 15th, 2011 Audio, javascript 17 Comments

Hyperaudio at the Mozilla Festival

This year has run contrary to previous years of my life in the sense that it seems to have lasted much longer than the year before. This may have something to do with a small addition to the family that arrived in March and the consequent ramping up of waking hours, but I prefer to think it’s because things are moving so quickly in that wonderful place we call the worldwide web, that it seems that too much has happened to compress into a year.

It was only a year ago for example, when I started tinkering with jPlayer to couple text and audio and was asked to show off a very small demo at the first Mozilla Festival in Barcelona last year.

A few months later I was introduced to and became involved with something known as Hyperaudio and was given the opportunity to create a couple of proof-of-concept demos : Denmark Radio’s Hyperdisken Demo and the Radiolab/Soundcloud collaboration ( a shout-out to Henrik Moltke for doing much of the groundwork for these demos and my colleagues at Happyworm without which they just wouldn’t have been possible).

Further on through the arc of this epic year, I took part in the Mozilla Knight Journalism challenge where I was encouraged to research and blog some ideas on a tool I called the Hyperaudio Pad. Happily I was flown over to Berlin with other like minded MoJo peeps, for a week of intense discussion, collaboration and hacking and managed to get the first semblance of an actual product out of the door.

Hyperaudio Pad

Which brings me in a round-about way to this year’s Mozilla Festival, where I will again be demoing and chatting about the coupling of text and media and the other things that Hyperaudio is (or could be) about. This all at the Science Fair on Friday, 4th of November and a Hyperaudio Workshop / Design Challenge on Saturday, 5th.

The Science Fair will be all about demos, chatting to people interested in the general Hyperaudio concept and making sure I don’t spill my drink over my laptop. Meanwhile in the workshop we hope to put the Hyperaudio Pad through it’s paces and actually make something with it, while gathering ideas and maybe hacking on some of them into the bargain. It should be a fun mix of hacks, hackers, designers, audio buffs and basically anybody curious enough to be involved. The session will be fairly free flow but the plan so far is to:

  • Briefly chat about and demo the Hyperaudio concept, what it can do and with whom we can collaborate.
  • Breakout into groups to come up with new ideas, applications and designs.
  • Reconvene and talk about the group’s ideas.
  • Breakout into groups to work on these ideas, whether it is creating a programme, UI mockups, story-boarding functionality or even developing small demos.
  • Creating something we can show other people – hopefully a program created with the Hyperaudio Pad but also some new ideas.

Hopefully we can cram this all into 3 hours. Folk from the BBC, Universal Subtitles, Sourcefabric and other cool people are planning to be in attendance, which should make for some interesting crossovers and fantastic opportunities to consult and maybe even influence organisations in a position to use the stuff we’re making. Additionally the BBC are providing us with some fantastic media to work with.

All will be revealed over the weekend, book your place and get your eyes and ears ready to be part of the Hyperaudio experience.

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Tuesday, November 1st, 2011 Audio, HTML5, Hyper Audio, jPlayer, Popcorn.js, Uncategorized 2 Comments

Introducing the Hyperaudio Pad (working title)

Mark Boas

Last week as part of the Mozilla News Lab, I took part in webinars with Shazna Nessa – Director of Interactive at the Associated Press in New York, Mohamed Nanabhay – an internet entrepreneur and Head of Online at Al Jazeera English and Oliver Reichenstein – CEO of iA (Information Architects, Inc.).

I have a few ideas on how we can create tools to help journalists. I mean journalists in the broadest sense – casual bloggers as well as hacks working for large news organizations. In previous weeks I have been in deep absorption of all the fantastic and varied information coming my way. Last week things started to fall into place. A seed of an idea that I’ve had at the back of my mind for some time pushed its way to the front and started to evolve.

Something that cropped up time and again was that if you are going to create tools for journalists, you should try and make them as easy to use as possible. The idea I hope to run with is a simple tool to allow users to assemble audio or video programs from different sources by using a paradigm that most people are already familiar with. I hope to build on my work something I’ve called hypertranscripts which strongly couple text and the spoken word in a way that is easily navigable and shareable.

The Problem

Editing, compiling and assembling audio or video usually requires fairly complex tools, this is compounded by the fact that it’s very difficult to ascertain the content of the media without actually playing through it.

The Solution?

I propose that we step back and consider other ways of representing this media content. In the case of journalistic pieces, this content usually includes the spoken word which we can represent using text by transcribing it. My idea is to use the text to represent the content and allow that text to be copied, pasted, dragged and dropped from document to document with associated media intact. The documents will take the form of hypertranscripts and this assemblage will all work within the context of my proposed application, going under the working title of the Hyperaudio Pad. (Suggestions welcome!) Note that the pasting of any content into a standard editor will result in hypertranscripted content that could exist largely independently of the application itself.

Some examples of hypertranscripts can be found in a couple of demos I worked on earlier this year:

Danish Radio Demo
Radiolab Demo

As the interface is largely text based I’m taking a great deal of inspiration from the elegance and simplicity of Oliver’s iAWriter. Here are a couple of rough sketches :

Edit Mode

Sketch of the Hyperaudio Pad in Edit Mode

Sketch of the Hyperaudio Pad in Edit Mode

Playback Mode

Hyperaudio Pad in Play Mode

Hyperaudio Pad in Play Mode

Working Together

Last week I’m happy to say that I found myself collaborating with other members of the News Lab, namely Julien Dorra and Samuel Huron, both of whom are working on related projects. These guys have some excellent ideas that relate to meta-data and mixed media that tie in with my own and I look forward to working with them in the future. Exciting stuff!

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Monday, August 1st, 2011 Audio, HTML5, Hyper Audio, inspiration, javascript 5 Comments

Accessibility, Community and Simplicity

Mark Boas

In last week’s Mozilla News Lab we were treated to webinars from Chris Heilmann, John Resig and Jesse James Garrett.

Chris (a Technical Evangelist for Mozilla), took us on a useful whistle-stop tour of HTML5 and friends, technologies that I certainly wish to take advantage of in my final project. I feel that there’s so much potential yet to be tapped, it’s difficult to know where to start, but I’ll definitely be using the new audio and video APIs and looking into offline storage. Chris also touched on accessibility, something that I want to bake into any tool I come up with. To me accessibility is interesting, not just from the perspective of users with disabilities but also because I hope to do is make news (and the tools to create news) more accessible to all people.

John’s talk was fascinating to me as a project coordinator of a JavaScript library, relating directly to the News Lab I found it interesting that many successful projects are a product of both good tools and strong community. The community aspect cannot be underestimated and is perhaps more important than the quality of the tool or service (which can always be improved by the community). I spoke about ‘Community Driven Development’ this year at FOSSCOMM and so is close to my heart, but to hear this confirmed by someone who has experienced success at the very highest level was great. I am now convinced that whatever ever form my final project takes, it will not only be community driven but it will have community built in, which to me means:

  • Providing forums and methods of communication and feedback with the initial release
  • Building extensibility into the tool so people can add functionality via plugins
  • Encouragement of collaboration – make it easy for people to get involved
  • Making sure that the documentation is comprehensive and clear (and can be contributed to)
  • Fanatical support and encouragement

I also attended the ‘extra’ webinar given by Jesse James. In some ways this was the most useful to me as it focussed on designing the user experience or UX, something I’m keen to learn more about and who better to tell me than the author of The Elements of User Experience. It was fascinating to take a peak at how UX experts like Jesse approached the subject of design. I sat there transfixed as he broke down the process and discussed ideas such as psychology, emotion and how the user feels and their relationship with a given product or tool. Jesse spoke about the personality of a product and how users relate to tools as they would another person, using similar parts of the brain as they do when relating to people.

I really want the tool I create to be as simple as possible to use, so my question to Jesse was :
Is it possible to make a product so simple that it doesn’t need a personality, or needs less? Or is the simplicity its personality?

The answer : “Simplicity is a personality.

Great. Hopefully I’m on the right track then.

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Monday, July 25th, 2011 HTML5, Uncategorized 1 Comment

Further Experimentation with Hyper Audio

Mark Boas

Following the fun we had making the Hyperdisken demo, I was happy to be asked by Mozilla, in collaboration with Radiolab and SoundCloud to help create another demo to show off the possibilities of hyper audio. This time we had an excellent Radiolab program as audio material and we wanted to get a little more ‘involved’. What was required was an application that would consist of many of the features of the Hyperdisken demo but also integrate deeply with SoundCloud API, and on top of this something extra, something to catch the eye.

Here’s what we came up with.


I was fortunate again to work with the ideas-forge known as Henrik Moltke, who collaborated early on with Paul Rouget to produce something he dubbed the ‘Word River’ – a CSS3 manipulated flowing river of words that dynamically picked up content from an HTML transcript. We were also keen to make a pure HTML5 based solution and Paul helped figure out the hooks into the SoundCloud API that would allow us to achieve that. We were also very lucky to be given a great design by the multi-talented Lee Martin, SoundCloud’s experimenter extraordinaire.

So with proof of concept and some visual bling firmly in hand I was tasked with making this baby fly. Luckily I had help. SoundCloud engineers were at hand to answer any questions and crucially we had great support and code contributions from the popcorn.js group. I also managed to talk jPlayer author and all round JS media guru and of course, colleague Mark Panaghiston into giving me a hand. So despite the tight deadlines we were pretty much set.

Henrik has already blogged about the ideas and functionality that make up the demo. I want to write a little about the technology used.

Although I found out in retrospect, not strictly essential, we once again used jPlayer as our audio base, we’re familiar with it and we can move fast using it. It also meant that we could take much of the functionality developed in previous demos and plug it right in. Again, the excellent Popcorn.js was the engine that drove all the time based display of text and images and dealt with the parsing of data. Steven Weerdenberg, active Popcornista from Seneca College, very kindly wrote a plugin that grabbed, parsed and presented comments (amongst other things) from the track we used hosted on SoundCloud. This is where the Popcorn framework comes into its own as a plugin oriented architecture, something we took advantage of when we converted both the transcript and the word river functionality into plug-ins.

So where did the data come from? Well again the transcript HTML doubled as the source for richer interaction when used by the word river plugin. I like this approach I have to say. It means you don’t have to be a programmer to come in and immediately understand the content and change it accordingly. I also like the fact that the transcript is a separate HTML file, it pleases the separatist in me and means that it works as a standalone resource. We also used the standard speaker notations as a type of meta-data, the word river plugin hiding these parts for the purpose of display but using them to colour code each speaker’s text.

This part of the transcript:

Transcript Markup
is used to create this ‘word river’:

Word River

and this interactive transcript :

Transcript Text

Data-wise, everything else came via the SoundCloud API, this included their trademark wave-form, both ogg and mp3 audio sources and all of the comments. We also hijacked the comments to make a crude content management system. The idea being that any comments posted by the Radiolab account with references to images in them, were picked up and displayed as images in the main content area, and did not show up as comments on the timeline. If two images were present it meant they were square, one and it was ‘widescreen’ a blank image was used to remove images when they were no longer needed.

The last pieces of the puzzle and one we’ve still some polish to apply to, (if polishing puzzles makes any sense to you) was getting it all working on the majority of tablets and mobile devices. Since this demo didn’t use Flash this was actually a possibility and we got our web designer Silvia Benvenuti to come out of maternity leave and sort this out for us at the 9th hour, leaving me quite literally holding the baby.

This was a tough gig but all in all I’m happy with what we achieved, everyone seemed to really enjoy taking part in the process, and I certainly enjoyed bringing it all together. Hopefully it will inspire both program makers, designers and developers to come together and explore the limits of what hyper-audio can do. As Inspiral Carpets would say, moo!


Source code for this project and other demos can be found on github

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