In short, the outside broadcast team encodes the UHD at a very high bit rate on site using a contribution encoder and gets it to Broadcasting House in London via IP where it goes in to the video router. This feeds the UHD distribution encoders which generate four bit rates of HEVC video up to 36 Mb/s (iPlayer HD is 5Mb/s for comparison). This is then packaged using the DVB-DASH standard so that 4 second long chunks of audio and video can be requested over the internet via a playlist called a manifest. This is served via an origin server in “the cloud”, which is then cached by servers in a BBC data centre to protect the origin. There is a further level of distribution provided by CDNs (content delivery networks) whose job is to serve very large amounts of traffic to very many of people across many ISPs who deliver the chunks to the connected TV. Easy.

We began building this chain in the spring but there were many unknowns. We needed to test contribution and distribution encoders, work out the best bit rates, try and bring all the networking together, organise the operational and support infrastructure - who pressed what button when etc. make sure we had levels of redundancy, test lots of different TVs and devices, ensure there was sufficient internet capacity. There was a long to do list. While we were building, we were also preparing our core services on iPlayer and iPlayer Radio for what we were expecting to be our biggest ever live streaming events.

There weren’t many opportunities to test our workflow. There are not that many UHD capable OB vans in the UK and they are often busy providing sports coverage for BT Sport and Sky so we only had a couple of events to test. We didn’t publicise these because we had no idea if they’d work at all.

We covered the FA Cup game between Southampton and West Brom (which I’ve now seen about fifty times), the Rugby League and some of the FA Cup final. By the end of this testing, we had a good feel for the workflow but we hadn’t put any significant load through the systems. We had only had a couple of thousand viewers.

We did discover that the bit rate for UHD averaged out at around 25Mb/s per viewer. We added this in to the total bandwidth predictions for the World Cup across the BBC to see how many concurrent users we could comfortably support and found that we would need to limit access to the trial. The standard HD and mobile streams were our first priority so we needed to ensure the trial didn’t take bandwidth needed for normal iPlayer and BBC Sport viewing.

We decided we’d be comfortable with a maximum number of around 60,000 concurrent UHD viewers, but that the number would be continually re-assessed during the tournament depending on overall performance. We also estimated there were maybe 2 million devices that might be capable of playing the UHD streams, hence the warnings about the streams being available on a first come, first served basis.

The Group Stages

The World Cup kicked off for us on the Friday 15th June as Egypt took on Uruguay. Trivia fans will want to know that the first ever UHD World Cup goal on the BBC was scored by Gimenez for Uruguay in the 89th minute.

The first couple of games ran relatively smoothly from a production point of view. We were closely monitoring feedback from audiences, via a survey and also through social media. The audience response was generally very positive, especially with regard to the picture quality. There were some comments about stuttering and juddering and speech getting out of sync despite viewers having high speed internet.

In the France v Australia game on the Saturday, some video didn’t arrive in time to be served to the audience. Unfortunately, the audio did arrive as DASH separates the two. This led to the audio becoming one segment out of sync - about four seconds. We failed over to the back-up. If you left the stream and came back, the issue was fixed, but if you stayed on the stream it remained faulty.

In the later game between Germany and Mexico, we had a router switch fail which caused more issues.

The quality of service that UHD demands of network infrastructure quickly roots out any problems, or components that are introducing latency. We replaced some optical connectors and noticed significant improvements in our logs and a reduction in complaints.

While we were fixing switches and networks, we took some other precautionary measures. We removed the lowest bit rate to give the distribution encoders less data to generate in each time period and we increased the wait time on the packagers. This increased our latency by a further 10 seconds. Not ideal but we wanted to keep the audience experience as smooth as possible.

We’d also noticed a number of comments on the size of the “BBC UHD” logo in the top right hand corner of the screen. This was set to a DPP (Digital Production Partnership) guideline but we all agreed it did look a bit big, so we reduced the size by 10 percent. We changed that on the Tuesday of the first week.

On the day of the first England game, 18th June, one of our contribution encoders had an issue during the preceding Belgium vs Panama match so we removed it from the chain and switched to the back-up. We used that for the rest of the tournament.

The England vs Tunisia game proved to be our most streamed live event up to that date. We stopped access to UHD in the first half for a short period of time as we re-balanced traffic across our CDNs to optimise performance. Things calmed down a bit and we re-enabled UHD access at half time. We had just over 35,000 UHD viewers at this point but were shipping around 5Tbits of data per second across all services.

We continued to work on our distribution and found and fixed further issues with networks and infrastructure along the distribution chain during the next few matches as we discovered them.

As the technical situation settled down, we felt confident enough to let the presentation team on BBC One mention the fact that there was UHD available. This was done by the commentators and an on-screen graphic. Doing so resulted in an immediate spike of 10,000 new viewers within a few seconds.

Two days later (27th of June) we had a serious external networking incident that caused a problems for viewers such as buffering and streams failing. We let the stream run, but there were only a few thousand watching. Things recovered for the second half of the South Korea vs Germany game. We asked Sport not to mention us for a little while just in case.

Round of 16/Wimbledon

As we moved in to the round of 16 in the World Cup, we added Centre Court coverage from Wimbledon. This added a bit of complication as we didn’t have enough UHD encoders to provide 2x resilience for both events. This meant a degree of source swapping for the back-ups.

As the network issues had now been resolved, we put back the lowest bit rate and reduced our packager waiting time by 20 seconds. This got our latency down to around 45 seconds - but it was very dependent on what device you were using.

Audiences started to increase, both for UHD and in general. For the Belgium vs. Japan game, we peaked at 37,300 concurrent UHD viewers, including football and Wimbledon.

Quarter Finals

Things started to hot up now. For the quarter final between Brazil and Belgium on Friday 6th July, we had 41,600 concurrent UHD viewers at the peak (including Wimbledon viewers). We still hadn’t hit our theoretical maximum limit by full time though.

England vs. Sweden was on Saturday 7th June with a 3pm kick off. We hit our UHD cap of just over 60,000 concurrent viewers half way through the first half. We pretty much stayed at this level for the rest of the match.

Semi Finals

We ran UHD for the France vs. Belgium semi final with no issues and just over 48,000 concurrent UHD viewers. The men’s semi-finals at Wimbledon provided a good soak test for our encoders and staff with play continuing until just after 11pm.

The Finals

The tennis final on Saturday 14th, and tennis and football finals on Sunday 15th July ran smoothly. A peak of 44,300 viewers saw Novak Djokovic and France win their respective tournaments, including the first penalty awarded with the help of VAR in a World Cup final. We don’t know if the VAR was in UHD or not.

We stopped the last stream around 7pm and put live UHD to bed for now.

Extra Time

As well as the technical issues we addressed at the time, there were a couple of other common comments that I’d like to address now.

Latency

The elephant in the room for live internet streaming is latency. Well, it’s in the room if you’re watching on Freeview. If you’re online it’ll be a minute or two yet.

Latency is less of an issue for everyday viewing, but it comes in to sharp focus when we look at sport. The usual latency for online streaming is between 30 and 90 seconds depending on your viewing device. For UHD we got latency down to between 45 seconds and a few minutes but it was very variable, again depending on the device. Interestingly, when we asked viewers about latency in our survey, while they wanted it to be as low as possible, most said they wouldn’t trade it off against picture quality.

The problem is one of scale versus speed. It is possible to stream video very quickly over the internet. It’s used all the time for video calling. The problems with low latency streaming are that it generally only supports small numbers of viewers, or it requires very proprietary hardware and software, or there is a significant reduction in quality or resilience. As more and more audiences move online this is becoming a significant issue for the whole industry.

Fortunately, it is also an issue the industry is beginning to address, both through developments by hardware and software vendors, and through the work of standards groups which the BBC is contributing to. Ultimately, we need to get the latency of IP delivery comparable to that of linear distribution and we, in BBC Platform and OTG have already started working through those issues with our partners in the industry.

It’s too dark

A couple of themes that came out of the user feedback were around the picture being too dark or the colours not being vibrant enough. Having worked with the production teams we think we have managed to improve some of the issues we found e.g. ensuring graphics are inserted at the correct level. For a more detailed assessment of some of the possible causes at the home end then please see this blog written by my R&D colleague Andrew Cotton.

It’s Coming Home

The UHD trial was a brilliant learning experience for us so we definitely consider it a success. It’s clear there’s lots more to learn, work on and improve, and massive events like the World Cup and Wimbledon really put our systems through their paces. We hope those that watched it had a good experience, and sincerest apologies for when it didn’t go so well. Our TV in the office buffered just as France scored in the semi-final and I was livid so I do understand how it can be frustrating at times. Thank you for trying it if you did.

We built the trial in such a way that it can be re-used and improved upon. This will allow the next trial, whatever it may be, to take advantage of all our experiences and fixes we’ve implemented this time around. Live streaming Ultra HD over the internet is at a very early stage, but we’ve taken an important step with this trial. We will continue to build our capability and make sure future audiences have a free-to-air option for live Ultra HD and HDR.

Meanwhile, in BBC Design + Engineering Media Services we’ve tackled some problems of our own around how to take these concepts and build a stable production process with the ultimate goal of handing over the management of our UHD streams to the production teams.

We’ve learned a lot over a first weekend of streams and will be following up with a summary of the issues we’ve encountered during matches and the changes we’ve made to reflect them at the end of the tournament. This post introduces the key components of a live stream and what we ended up building out for UHD.

For Media Services, a live stream at the BBC generally consists of the following base components:

• Contribution decoding — where the video signal from the outside broadcast site is received back in a BBC site and decoded.
• Distribution encoding — the signal is then encoded into the final format used for distribution to users, including the full adaptive bit-rate (ABR) set of encodes and structure for chunked-HTTP delivery
• Packaging — this encoded media is then packaged into the correct fragmented MP4 containers with appropriate metadata and manifests that can be served to users over HTTP
• Distribution origins — the BBC’s origin servers that downstream caches use to collect streaming content
• Content Delivery Networks — huge third-party networks and caches that provide the scale of delivery needed to handle the BBC’s streams to ISPs and other edge networks
• Internet Service Providers — the companies our audience pay to receive their internet connection at their home or business, or on their mobile devices
• Client Devices — your TV, mobile, or PC

For our existing HD and radio workflows, this is a relatively well defined set of services that we have run for several years now. While there’s plenty we want to improve here, and we always are, it works. For example, two years ago, for the UEFA European Championship, managing ~2.4Tbps was a squeeze at multiple points in the delivery chain, but recently we comfortably managed a record-breaking 2.8Tbps of peak traffic during the Royal Wedding. We broke that on Friday by reaching 3.4Tbps during our first World Cup match, and shortly after broke that one too with just over 5Tbps during the England opening game against Tunisia on Monday.

For UHD however, we’ve had to review every part of this chain. In some areas this involved choosing vendors, for others it involved building new services. After a lot of work across BBC R&D, Broadcast Engineering, Media Services, TV Platforms and the Online Technology Group (OTG), we’ve managed to build our first attempt. It’s far from perfect, but here’s how we ended up where we are for our first iteration.

Contribution Decoding

Video services locally generally use a set of cabling and signalling standards called SDI. Since UHD is essentially four times the amount of data, Quad-SDI is just four SDI signals, each carrying one quadrant of the stream.

As a raw signal, this would be tens of gigabits per seconds over the internet from Russia, so would be infeasible. Instead, a ‘contribution’ encode is sent to us. This is an IP stream that is quickly encoded, optimised for low latency rather than very low bit-rates; for the World Cup we’ve opted for a 120Mbps signal. This is then sent back to the UK, where our contribution decoders convert this back into a Quad-SDI signal output over 4 SDI cables.

Distribution encoding

The BBC generally prefers to launch new services using cloud services — whether fully managed or running ourselves on cloud infrastructure.

All new ‘regular’ live services we launch, such as World 2020’s Guraji, Telugu, Punjabi and Marathi bulletins, use cloud-based distribution encoding. Meanwhile, we’re hoping to move as much of our legacy on-premise encoding kit onto a cloud product as they reach the end of their useful life.

Unfortunately, for live UHD encoding, most encoding architectures require all ABR representations to be produced on the same instance, and it is very hard to get enough compute resource on one instance in the cloud to achieve this.

Therefore, for this we had to buy physical appliances — each of which (with 4 GPUs) can support only one UHD output. Even then, we had to remove some of the ABR representations we hoped to offer.

Distribution Packaging

After distribution encoding, we normally use a separate distribution packager to package the encoded segments into the formats required by end client devices. For regular HD content, the encoder delivers this to the packager using Microsoft’s Smooth Streaming format over an HTTP POST. Unfortunately, our encoder does not support HEVC video in a Smooth output (understandably so, as how to do so was only defined in March), so we were unable to use our normal packaging component.

Our saviours here, as is often the case, were our colleagues in BBC R&D. They for some time have had an internal ‘reference’ packager that is used for internal tests and for some small public trials such as Radio 3 in surround and lossless audio that have been run during the Proms in recent years. This packager operates a ‘pull’ model, preparing chunks for distribution as the encoder writes the encoded output to disk, so removes our Smooth dependency. We’ve worked with the team there to get some more physical, real world servers installed, built and working in a largely production-ready state. The R&D packager then outputs the packaged material into an Amazon Web Services S3 bucket.

Distribution Origin

Our distribution origin services for live serve us well. These are caching/load balancing appliances today. Capacity planning for the initial desire of up to two concurrent UHD streams through them though suggested that we would be reaching the limits of what these devices were capable of, so we’ve looked to replace these too.

For on demand, we have long used our in-house Radix solution. Our OTG colleagues have now set up a new Radix pool for handling UHD content and everything here is now looking pretty good.

Content Delivery Networks & Internet Service Providers

Currently, the BBC’s top streaming bit-rate is 5Mbps for HD content. The 36Mbps we’re offering for UHD is therefore proving to be quite a challenge in terms of distribution capacity.

It’s for this reason that we announced a strictly limited number of entries into the UHD trial service at the same time — there just isn’t enough distribution capacity in the UK if every compatible device tries to watch a UHD stream at the same time. We’ll be reviewing this number continually during matches to try and find the right balance between offering the trial to as many users as possible and protecting the stability of internet distribution — both for us and our commercial CDN’s other customers. There’s a few unknowns we have that are resulting in us being conservative initially:

• The number of audience members who watch in HD via iPlayer who will now watch in UHD instead
• The number of audience members who watch via traditional broadcast methods (Freeview/Freesat etc) that will now watch in UHD instead — this is the first time we are offering higher quality online compared to broadcast so we can’t predict how many people we convert to IP from broadcast
• The accuracy of our bit-rate modelling from earlier trials — we have an understanding of how many devices played each of the different bit-rates based on the earlier trials and our live UHD test loop; but didn't know how the model would hold up until we saw our first England match

This ultimately means we’re monitoring very closely and this limit may move up and down as we learn more about how the service is used.

Client Devices

A substantial testing process has been underway to get as many devices as possible on the trial. Additionally, whilst we’ve offered DVB-DASH streams before, UHD is our first DASH-only service so there was a lot of effort around tightening up support and moving more devices over from other streaming formats. The key things we’ve been looking for are stable decoding of a 36Mbps stream and support for either BT.2020 SDR or BT.2100 HLG HDR.

When set-top boxes are involved, we also have to factor in whether the connected display can present the signal — it would be a waste for us to deliver a 36Mbps UHD signal to a panel that can only display a 1280x720 HD image. Therefore, we have had to add code to detect the capability of the connected display and only offer UHD where the connected display is capable. There currently lacks a standard for detecting these capabilities, which made this quite difficult.

Next Steps

There will be lots to learn from this summer’s UHD sport events, and we’ll be going back to look at how to improve the broadcast chain. We’ll also be doing a lot more analysis on how UHD changes when and where the audience consumes content.

Oh, and by the way, Media Services is hiring!

With the old workflow, we published video by creating 23 media files, each containing an audio and video component. These were stored and delivered separately. Some distribution protocols relied on special services from third parties. As a result, we were not efficient in storage or workflow and also less resilient.

The video profiles had also grown over the years in a piecemeal way as new devices came out and support was needed. This resulted in a mix that was not optimized for re-use across devices and did not offer the best experience on all devices.

We decided to make big changes.

The new video profiles have been designed from scratch. This meant we had the opportunity to not only improve the quality of the video, but also make the entire set work better together. Different devices get the best video for them, while still reusing assets between devices in the most efficient way.

The Media Services team worked closely with BBC R&D to define 14 video profiles and 5 audio profiles that can be combined to make ABR (Adaptive Bit-Rate) sets for all supported devices, from mobile phones connected over a cellular network, which gets 56Kbit/s stream to ensure video will continue to play even with slow connections, to computers and connected TVs, which will now get up to 5Mbit/s 720p video at 50fps.

The HD stream will also become adaptive set, so HD will play if your connection is fast enough, but the video will reduce quality and continue to play rather than buffering or stop if your connection speeds fluctuate. This way you always get the best quality video that can be played.

BBC R&D will publish more details about the details and design process of the new video and audio profiles in a blog coming soon.

A key to making this work was a switch to chunked HTTP video formats. We already use these for our live streams and with this change all new content will only be available via chunked HTTP distribution. That is HDS (HTTP Dynamic Streaming), to replace the current RTMP for Flash based players, HLS (HTTP Live Streaming) for iOS and other connected devices.

The distribution model was the other thing we changed. This was a much bigger deal. Switching from 23 separate files to a single multi-tracked file. This single file is then reference to create all the media variants we need to support the different combinations of ABR sets and distribution protocol. As a result, we store a single media file and can have over 30 variant combinations derived from it. Each variant will offer tailored ABR set in specific distribution protocol - for example, mobile phones connected on Wi-Fi as HLS, or for desktop computers wanting HD with a Flash player.

Our transcode workflow changed from creating and publishing separate assets, to transcoding all the video and audio components and creating and publishing a single asset also with data about all the variant combinations. This provided new levels of flexibility that means we can create new variants and distribute in new ways, without having to re-transcode media. We can now just add or re-write data about all existing content and it can work in a new way.

The reason we can store a single file and still serve out so many variants from that file is the addition of a dynamic packaging and caching layer. What this means is that content for a specific type of device is created on first request and distributed. Subsequent requests are fulfilled from a cached version, either in our delivery chain, or by the CDNs (Content Delivery Networks) that deliver the video to the audience. More detail on this will follow in a blog post from the Media Distribution team.

One of the big benefits all this work provides is the ability to start distributing content as DASH (Dynamic Adaptive Streaming over HTTP). Collaboration between BBC R&D and Media Services, as well as with our packaging software provider (Unified Streaming) and the engineering teams that build the BBC’s TV and Mobile products and the Media Player team, means we can soon start offering streams as DASH on supported connected TV devices, some mobiles and as an opt-in on desktops via HTML5. More details on DASH will also come in future blogs posts.

We're not finished yet. This phase of work may be coming to an end, but we've created a platform to build on that means we can continue to improve and innovate on the both quality of the video and the ways it can be distributed. We are also working to bring all the video across BBC Digital into the fold, so not just catch-up programmes on iPlayer, but all clips and live events too. Then improvements that Video Factory has made and will continue to make can benefit all video on BBC Digital products.

Just for any new readers, I am head of technology for BBC HD & 3D and this is an update on the next phase of the BBC 3D trial. We have now moved from sport, music and animation to drama!

Mr Stink is a TV adaptation of the book by David Walliams. I won't give anything away in the post for those who love the book and for those who have never heard of it - just watch!

In this post I want to give you an overview of some the technology and processes used during the making of Mr Stink with comments from a few of the people involved.

Mr Stink transmits in 2D on BBC One & BBC One HD on Sunday 23 December at 6.30 and is repeated on Boxing Day at 12.40. The 3D transmission is on BBC HD on Sunday 23 December at 6.30 and shortly after on BBC iPlayer for seven days

Mr Stink (Hugh Bonneville) and Chloe (Nell Toger-Free) in Mr Stink

Mr Stink is the first programme we've done during the trial where the 2D and 3D versions were shot at the same time with the 2D being taken from one of the 3D cameras. The cameras were mounted on mirror rigs and for those interested in the details, these were a 3ality Technica Atom and a P+S TECHNIK Freestyle rig, each fitted with two RED Epic cameras and Angenieux Optimo matched lenses.

This is what Philipp Blaubach, the director of photography (DoP) working on Mr Stink, thought of idea to shoot in 3D:

It was a great opportunity for me to shoot a film that has been specifically designed for 3D. As a cinematographer it is a very different approach both logistically and creatively, and it was important in preproduction to work out the do's and don'ts. Having a close collaboration with the stereographer and the director meant we really embraced the strengths of 3D and found a visual style that works especially for this comedy genre. We liked slightly cartoonish and quirky compositions, like in the films of Wes Anderson or the Coen Brothers, and the fact that 3D works particularly well with wide angles even for close ups suited the style we were after perfectly.

One of the camera rigs with DoP Philipp Blaubach!

Chris Parks from Vision3 was the stereo supervisor on the programme and also commented;

The choice of rigs and cameras was determined by a number of factors. We wanted to be able to change setups quickly so we chose to use zooms as variable primes. We also wanted a reasonably small and light rig so we could be more mobile and wasn't too off-putting to actors. We also wanted it to be cost effective so that on certain days we could afford to bring in a second unit. The Atom allowed us to put on a larger mirror box so the DoP could use a 16mm lens with the Epic at five thousand. For monitoring we used a 46in JVC as we felt it was important for the director and DoP to be able to see the playback in as near to a real world situation as possible.

Mr Stink was framed for a wider aspect ratio than the normal 16:9. Philipp shot in the cinema aspect ratio that's sometimes referred to as 21:9 but more accurately it was actually 2.35:1. This gives black bars at the top and bottom that effectively become a new screen boundary. However as it's only an electronic boundary that allowed us to try some interesting effects.

Philipp said;

We composed the film for a 2.35 aspect ratio and during the depth grade there were a couple of instances where we could move the action into negative space and virtually make it overlap the letterbox. The 3D is especially effective in those moments as you feel the objects literally coming into your living room.

Framing for 2.35:1 (3D is displayed using anaglyph if anyone wants a quick preview but, the programme will not be transmitted in anaglyph).

As I said earlier the programme was shot using a single camera rig with an occasional second rig. This is different to the multi-camera set-ups we've used for the studio and live programmes that have been in the trail so far. This meant that instead of the stereographer adjusting each camera to match the 3D depth during the shoot, a 'depth grade' process was added to the final post-production stage.

Just like a colour matching or grading session that adjusts the colour and exposure of each shot to make them match, the depth grade matches the amount of 3D in each shot so there are no sudden jumps on shot changes.

Again for interest, the programme used the company ONSIGHT's 'Mistika' equipment to carry out the colour and depth grade with colourist David Gonzalez Lozano and Philipp Blaubach (the DoP) along with Matthew Smith who was the stereographer on the project working under Chris.

Matthew was responsible for the on-set Stereo 3D decisions working closely with the director and DoP and followed this through to the depth grading session during the final post-production.

The two TX lines

Mistika screen shot (3D is displayed as anaglyph if anyone wants a quick preview but remember the programme will not be transmitted in anaglyph).

The last time I saw the programme was just before the final colour and depth grading sessions, so I won't see the final results until it's transmitted.

As usual I am really keen to get your reactions to the programme and what you thought of the 3D but I will be away over Christmas and for a week in the New Year so replies to comments may not be prompt until I'm back around 8 or 9 January. In the mean time I wish you all a very, very merry Christmas and a happy new year - in advance!

Andy Quested is chief technologist HD & 3D, BBC Technology.

3D transmissions over the Christmas period:

Mr Stink 23 December 6.30pm
Killer Dinosaurs 25 December 2.05pm
The Queen 25th December 3.00pm

Remember to set your TV to Side by Side mode on the BBC HD Channel:

Freeview Channel 102
Freesat Channel 109
Sky Channel 169
YouView Channel 102
Virgin Channel 187

Read more about the making of Mr Stink in 3D on the About the BBC blog.

Side by Side (SbyS) image

This is a very brief post as it's more a request for comment than an explanation of a process.

On the 19th August at 17:35 the BBC HD Channel will be transmitting "Ulimate Killers".

This single programme has been made from the very successful Planet Dinosaur series.

The programme is only available in 3D so we will be testing the "Watch in 2D" application on Freeview and Freesat.

I'd like you to comment on this blog post to tell me what you think of the "Watch in 2D" application. Unfortunately the application is not available on Cable or the Sky set top boxes yet.

The programme will also be available on BBC iPlayer. There will be several different encoded versions but as we are letting the automation take care of encoding I won't know what will happen until you do on some platforms!

All versions will be side by side so we also know not all devices will be able to convert them to a viewable 3D image.

What I do know is the image via the Freesat, Freeview and Virgin TiVo iPlayer apps will be 1920 x 1080 side by side. This is a new test encoding based on the work the iPlayer team carried out before the Olympics.

If you do want to comment, can you also let me know the:

1. platform you used and the device e.g. Freeview set top box, PC or Mac via DVB card, PC or Mac via bbc.co.uk/iPlayer...
2. rough measured speed of your internet connection
3. make and model of TV and or set top box

I can't guarantee individual replies but we do want to collate as much information as possible to assess our next steps

Many thanks.

Andy Quested is Head of Technology, BBC HD & 3D

Hi. I'm Tim Plyming and I'm the project lead for the BBC's Super Hi-Vision trials taking place during the London 2012 Olympics.

As I spoke about in the video above, I've just finished a fantastic week of Super Hi-Vision filming in London with a crew made up of staff from Japanese broadcaster NHK and the BBC. Given this and the fact we're now 11 days before the start of the Games, I thought this would be a great opportunity to tell you a bit more about the BBC's Super Hi Vision trials.

So, what is Super Hi-Vision?

Developed by NHK, Super Hi-Vision is an Ultra High Definition television format combining images 16 times the resolution of High Definition television with a 22.2 multichannel surround sound. Experienced on a big screen, the effect is of feeling like actually being at an event.

The London 2012 Olympics will be the first time this ground-breaking technology will be used to deliver exceptional quality content in the UK, so I'm extremely excited that you will be able to experience it for the very first time.

Building up to Games Time

As mentioned earlier, we've been filming at a range of iconic London landmarks over the last couple of weeks for a special film which will play ahead of the start of the Olympic Games. It was particularly exciting to capture what I think will be one of the iconic Olympic images of Tower Bridge, dressing with the Olympic rings, in Super Hi-Vision.

We have been using a brand new Super Hi-Vision camera and microphone and a specially adapted outside broadcast truck which have all been shipped from Japan to the UK.

At the same time in our R&D test studio (TC0) at BBC Television Centre in west London, a talented group of colleagues from the BBC's Research & Development have been working with NHK to build the first Olympic Super Hi-Vision production studio.

A history of innovative partnerships

Our Super Hi-Vision trials build on the BBC's history of innovation - experimenting with new broadcasting technologies and looking at new ways to bring quality BBC content to audiences in the future.

The Olympics has always been one of those moments where the BBC showcases new broadcast technology - due to the size and scale of this momentous event. Looking back at past Games:

• First TV broadcast - at the last Olympic Games in London in 1948, the BBC used specially built outside broadcast trucks and cameras to bring all the excitement of an Olympic Games to audiences at home on TV for the first time.
• First live colour transmission - in 1968 the Olympic Games was transmitted live in colour for the first time across the Pacific ocean to audiences in the United States
• First HD broadcast - in 1984 experimental High Definition cameras were used for the first time to capture an Olympic Games

The London 2012 Olympic Games will be the first to be captured in Super Hi-Vision - using the only Super Hi-Vision equipment in the world.

Three cameras will capture sporting action from the Olympic Stadium, Aquatic Centre, Velodrome and Basketball Arena. Alongside highlight packages, we will be showing live coverage of the opening and closing ceremonies, the 100m final live as well as a whole day of action from the Aquatic Centre.

Working with over ten global partners, the Super Hi-Vision signal is being sent around the world. In the UK we are working in partnership with the JANET high bandwidth academic network to bring Olympic content to our audiences at our public viewing venues.

Where can you experience Super Hi Vision?

Working with teams at three venues across the UK, we are also building special public viewing theatres which will present Super Hi-Vision on giant screens with special speaker rigs to recreate the 22.2. multichannel sound.

Our viewing theatres are:

1. London: BBC Broadcasting House
2. Glasgow: BBC Pacific Quay
3. Bradford: National Media Museum

Regular screenings take place Monday 23rd July - Sunday 12th August. We've also just released tickets for another six sessions to come and see (and hear) this amazing technology for yourself - but be quick as they sell out fast.

Screenings in London and Glasgow can be booked through the BBC ticketing website at bbc.co.uk/showsandtours/events/. Screenings in Bradford can be booked through nationalmediamuseum.org.uk.

Viewing theatres are also being set up in Tokyo and Fukushima in Japan and Washington DC in the United States.

I really hope you get the chance to experience Super Hi-Vision for yourself and look forward to hearing about your experience or what you think of our plans.

We'll keep you updated in the build up to the Games - and look forward to sharing our learnings with you from this exciting trial.

Tim Plyming is the project executive for digital services, Editor Live Sites and leading the partnership between BBC, NHK and OBS to capture the Olympic Games in Super Hi-Vision.