Archives for March 2008

Coyopa takes shape

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James Cridland James Cridland | 16:36 UK time, Monday, 31 March 2008

A few weeks back, I posted a few messages here about the work we're doing to change the way we're streaming radio. We're calling the technical work "Project Coyopa", after the Mayan god of thunderous noises. (No, I didn't name it).

Just to keep you abreast of the work we're doing: here's a picture of one half of the Coyopa system, currently in testing somewhere in the UK.


This is recording BBC Radio's various national services via satellite (we'll be taking a direct feed in future); recording it and encoding it into various formats as quickly as possible after transmission (which is why there's so much hardware here). And it works as designed. Which is nice, and quite a relief.

Next thing to do is to sling this into a big lorry, drive it to Broadcasting House, and plumb it in. It's set to go live in July, though there are some improvements happening in May (a small change from the previously advertised schedule).

Better sounding radio online? It's on the way.

Still Playing in the Cloud

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Chris Bowley Chris Bowley | 16:54 UK time, Thursday, 27 March 2008

Matt Wood (we really need to sort him out his own login) gives an update on his XMPP experiements...

I've made a little time recently to move my previous XMPP experiments forward a little. Here are the results.

Live Text

I've started echoing the stream of text that passes across the little screens of DAB radios into XMPP space. We call it 'live text' and it's frequently entered by production staff in a studio as a show is actually being broadcast, so it's timely but with a very short half-life. Seemed like a good fit for XMPP delivery!

You can find the live text at point your client at the group chats at,, Feel free to hook this into your own applications...

The backend was again written with XMPP4R which I'm still finding very easy to work with.

We currently use a very lightweight but proprietary protocol and server to get this text into the Flash widgets for iPlayer and the radio network sites. On the assumption that it would be just better to use an open protocol for this I'm hoping to spend some time with Tsung soon to see whether we can make XMPP scale comparably. If you've any scaling war stories I'd really like to hear them - to be competitive we'll need to support at least 100,000 concurrent clients without breaking a sweat.


By popular request I've switched federation on at - this means you no longer need a account to subscribe to the now playing and live text streems - just use your regular jid or gmail account.

XMPP over HTTP and Javascript

Paul asked me whether XMPP could go through firewalls and the answer is YES. This is important if you've a large client base any number of whom may be behind a corporate firewall that only allows 'safe' traffic through. The BOSH spec allows you to tunnel XMPP over HTTP in a way that doesn't hammer your server in a polling frenzy but which still respects timely content deliver and which plays nicely with proxies.

I've hacked together a couple of small demos to show how this works, and how easy it can be to put together XMPP apps with Javascript. They're built on top of JSJaC, a compact and robust XMPP client library which handles the BOSH mechanics for you - your code sees a single, 'persistent' connection object. These implementations are pretty naive and I'm going to maintain that this is to make the code as easy to follow as possible.

Very Live Text!

The first pulls the live text for Radio 4 into your browser and hopefully shows how little code you need to script XMPP from your browser. It also shows you how to do 'anonymous' logins, and how to work with JSJaC's callback-based programming model.


The second tracks the 'now playing' feed I presented last time. Here you can see basic support for the XMPP extensions you need to get 'user tunes' working (rosters, entity capabilities and personal eventing via pubsub) layered on top of JSJaC.

I also noticed that the tune spec was updated to allow you to publish your rating of the tune that's currently playing. So with this app you can click 'Pop!' or 'Drop!' buttons to publish your (dis-)pleasure with our playlists. From a public service perspective a federated standard for scrobbling certainly seems kind of interesting, especially if you worry about who owns your attention profile.


Next up is some benchmarking with Tsung, and I've a couple more toys in the pipeline. More here as it happens...

Your comments are, of course, very welcome!

SXSW Interactive 2008

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Chris Bowley Chris Bowley | 11:53 UK time, Monday, 17 March 2008

Arriving in Austin for South by Southwest Interactive, the first thing you notice is that everyone is clutching an iPhone (this being the BBC, I should point out that other mobile phones are available). This tells you much about web geeks' desire for Apple products but also about the direction in which the industry is moving: experience, community and immediacy are everything. (I would be willing to bet that more tweets are sent during the five day conference than at any time throughout the year.)

SXSW covers a wide range of media topics across music and film and illustrates how interactive is not only another medium on which to offer services but is very much media itself. With hundreds of sessions and around 7,500 people attending the interactive festival there is too much on offer for us to fully explore but there are lots of write-ups across the web.

Mark Zuckerber keynote

The biggest talking point of the five-day conference was the keynote interview of Facebook CEO Mark Zuckerberg by Sarah Lacy and I managed to grab a seat at the back. Zuckerberg is only 23 and is certainly no politician or powerful public speaker and his repeatedly closed answers were in stark contrast to the transparency and openness of the majority of speakers. Lacy did not help him though and in the end the audience's questions targeted her as much as their dislike for some of Facebook's more controversial features.

While the focus for most of the panels was interaction design, covering topics from kinetic computing to geo-location, there were a number of excellent technical sessions. Scalability boot camp and A critical look at Open ID have given me a few things to investigate for two soon-to-be-released applications. Identity, privacy and security on the web are hot topics and Open ID's decentralised approach is an attempt to make things more transparent, but it is by no means a perfect solution. Panels such as this which debated opinions on a particular issue were both engaging and reassuring and I left feeling I understood more but also wanted to investigate further. Panels such as Emotional by design which attempted to present a collaborative view on a subject were often weak and offered little to walk away with.

Panels on the latest round of the browser wars and the latest evolution of JavaScript libraries exposed the issues around creating a unified experience for everyone and what vendors, standards bodies and the development community are doing about it. It seems that while the vendors sit on standards bodies and argue about how to implement padding and margins (amongst other things), the community is hard at work making their current offerings behave. Representitives from jQuery, Prototype, Scriptaculous and Dojo were not there to argue which was the best but discussed how and why they have implemented features in their libraries and best practices for using them.

Unfortunately the session I was most looking forward to, Taking your web talent to the video game industry, was very disappointing. The only conclusion I was left with: make flash games (!)

SXSW also presents ample opportunity to meet new and interesting people and to learn more about their thoughts and methods. Veterans will tell you the important stuff happens outside of the panel sessions. We certainly made the most of it.

Podcasts on other mobile devices

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Simon Cross Simon Cross | 10:27 UK time, Monday, 17 March 2008

I’m starting to sound like a stuck record. All my posts on this blog seem to be about Podcasting. Specifically, making our podcasts available on other platforms. Annoyingly, this post is no different, but I think its still worthy of mentioning some more cool work we’ve done to optimise our mini-audio-on-demand service for new mobile devices.

First we did the iPhone, which was swish, and very zeitgeisty. But we always said we’d be doing the same for other devices; so here's our first simple-but-elegant iteration of this.

Screenshot of BBC Podcasts on the Sony PSP

What we’ve built is our entire podcast directory in distilled form, with layout and markup optimised for three new device types, the Nokia N95 and other newer Nseries phones, the Sony PSP, and a generic xHTML version for other web-capable mobile devices. for Nokia Nseries phone for the Sony PSP for generic mobile devices

... or you can just go to on your preferred device, and we’ll do the rest.

Screenshot of BBC Podcasts on the Nokia N95

The reason behind this is that 2007/2008 are the years that have seen the first mass-market wi-fi capable phones – the N95 being the biggest seller by far – but also the iPhone of course. In addition, increased memory on these devices, and the BBC’s deal with The Cloud means we have the right climate for mobile podcasting to be a viable product.

We put a crack team on this, and we’re really chuffed with the results. All the credit goes to Max Lehmann, Tim Broom, Wolfgang Weidner and James Whitmarsh for making it happen.

So how did we choose these devices? Our excellent mobile teams here at the BBC gave us stats on device takeup, and we matched these with the user-agents our server sees downloading podcasts. The top device classes were the N95 and the PSP – the latter of which accounted for a staggering 5% of all podcast downloads. Others notable devices were the Windows Mobile and Blackberry device classes.

There's more on how and why we did this, along with some background on the contentious decisions we had to make after the jump...

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Streaming radio online - your comments

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James Cridland James Cridland | 12:43 UK time, Wednesday, 12 March 2008

Over on the BBC Internet blog a few weeks ago, I posted a piece about planned changes to our streaming, for both live and on-demand radio. It's a piece that has got quite a lot of comment, so (in order that I don't take over the Internet blog and also to highlight its content here) I thought it worth replying to the comments in turn. Which I'll do, as they say in all the best blogs, after the jump.

(I've always wanted to say that).

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What's that star on the wall?

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Michael Smethurst Michael Smethurst | 13:07 UK time, Wednesday, 5 March 2008


A few of us recently went along to Semantic Camp and gave a presentation on our linked data plans for /programmes, /music and onwards.

The presentation is now available here. Sorry for the delay.

Thanks to Tom and Daniel for organising a great day.

And thanks again to Sophie Walpole for finding the money to make the work so far possible...

Links for 03-03-08

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Chris Bowley Chris Bowley | 14:56 UK time, Monday, 3 March 2008

It's official, games revenues overtake music at retail
In the UK at least. But its hardly surprising when so many music sales take place online.

This week sees the start of SXSWeek 2008
Yasser and I will be there for the Interactive Festival. Following the above news, I'm personally looking forward to this session :-)

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