Nokia N8 photography and Dolby sound FAQs

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Damian Dinning, the designer of the Nokia N8's camera system, has been monitoring reactions to news about the N8's much vaunted camera, and has compiled a comprehensive set of FAQ's. In this, Damian covers topics ranging from why is there no lens cover to how to best hold the N8 while recording video, and discusses the performance of the N8's sensor, the largest ever used in a mobile phone. Also published today is an interview with Jonathan Jowitt from Dolby, which goes to equal amounts of obscene detail in looking at the digital audio capabilities that underpin the N8. Read on for some take-home points from each.

Nokia N8 up close

It's certainly unusual to be able to get so much feedback to the public from one of the designers of any phone component, so we hope to see more in the way of engineers like Damian stepping up to talk to the public about such a widely anticipated device. The whole FAQ can be found here, although here are some highlights:

  • The form factor of the N8 is now well known and some people have questioned the wisdom of leaving out a sliding camera cover. Damian reports that the N8 lens is made from toughened glass, and that many sliding-cover designs in the past have had recesses that held on to dirt, and so a bare lens is actually easier to keep clean.
       
  • Damian confirmed that the N8 will not have RAW output. While he and the team recognises the need for this, they are confident that the current JPEG algorithms will provide pleasing results. Also, Damian said that the current JPEG algorithms will be made more efficient because of the low-noise output from the N8's camera sensor. While the JPEG algorithms are staying the same, Damian et al have been tweaking the other 300 settings in the N8 sensor, which explain why they are using non-standard ISO levels, such as 105, instead of the familiar 100.
       
  • While the N86 was known for its variable aperture camera, it surprised some that the N8 will not have the same feature. Again, it seems that many of the choices with the N8 have been facilitated by the low-noise sensor, which provides better low-light performance, and in very bright light, the high-quality optics are enhanced with a neutral density filter.
       
  • Speed has also been an area of development with the N8's camera. Viewfinder lag has been brought down to 100ms, and shutter lag is 350ms, making a shot possible in less than half a second.
        
  • When it comes to video capture, we might expect to see more mixed results, as Damian stated "We will be looking for opportunities to further improve the video performance in later software updates". Damian also mentioned that a jelly-like effect might be seen in video capture. While the N8 uses a mechanical shutter for still image capture, video capture doesn't and instead uses what he called a rolling stutter. As with any camera, the N8 reads its camera sensor from the top-left pixel to the bottom-right pixel. If the N8 has moved a noticeable amount in the time it takes to do this for each video frame, then the sensor will effectively be reading a different image than the one it started from, all within the time of a video frame.
        
  • Audio capture while filming videos is performed by a pair of digital microphones, providing stereo input, encoded at 128kbps AAC at 48KHz. These are claimed to pick out voices well with loud background noise. However, Damian warns that the mics are sensitive enough to pick up hand movement on the phone, and so users will have to practice holding the phone correctly to operate the video camera while not causing too much noise on the microphones (it seems that holding the phone the right way is a popular bit of advice these days!)

From the Jonathan Jowitt interview, we've learned:

experience into a mobile phone, and where it might all lead…
JJ:  ‘The video file format is MPEG-4, there’s nothing special about it. It uses traditional video encoding and traditional Dolby encoding in the audio domain.
Thee handset (which has 16GB of internal memory) would probably store thirty or forty ninety-minute-type movies, you’ll get a good thirty films on the  device. So we see the N8 as a kind of portable hardware version of a kind of disc player… a Blu-ray disc player actually, because it’s slightly better quality than you get out of a DVD player.’
HCC: So it’s the inclusion of Dolby Digital Plus multichannel decoding over HDMI that makes the N8 a game changer?  
JJ: ‘Well, some of the people who are in traditional broadcasts, or what you might call traditional shiny media, are questioning whether this has started to open the content portability question again.
'You can take the file format and put it into some televisions and they will just play the file. We didn’t originally create Dolby Digital Plus for portability. In fact, we didn’t expect handset manufacturers to be clamouring for 5.1 at all just yet. It’s not caught us by surprise, it was always on our roadmap, it’s just come in a bit earlier than we expected. And Nokia has embraced it. There are some handsets out of Korea that are already 5.1, I think there’s a couple of Samsungs, a couple of LGs, but I don’t think those devices have made it to Europe yet. But this is the first with Dolby Digital Plus, so it’s very future-proof.
'And the great thing about the media file, of course, is that you don’t need an AVR to play it, you get a great experience on the go. We make sure you can hear the dialogue and make sure it’s nice and clear, it’s not swamped. Dolby Digital Plus does a real-time down-mix so that you can listen to it into your earphone speakers.’
HCC: ‘You have already introduced Dolby Headphone technology (for a surround experience with standard headphones), is that incorporated into the Nokia N8?’
JJ: ‘Not on this first model’
HCC: Is that not like a kind of natural thing to do?
JJ: ‘I think it’ll be surprising not to see Dolby Headphone on more phones in the future. This is very much about the connected home experience. You can picture Dolby Headphone being more suitable for a portable experience. But, because they’re carrying the same core decoders, the same file will play. So it means content providers don’t have to do special formatting for all this range of devices that’s going to come out, that will take it to the next uncompromised level, as we like to call it.’
HCC: How compatible is that device with other file formats? Can it play an AVI or an MKV that’s got a multi-channel soundtrack…
JJ: ‘I think the Nokia handset does open MKV files. I’m not sure if it plays native AVIs, because a native AVI would be far too big without any compression. In reality, the industry is standarising on H.264. The BBC iPlayer HD throws images out in exactly the same MPEG-4 format. So, you can see where this is coming to that central point. The industry is going towards an MPEG container; H.264 720p with a standardised audio stream based around 5.1.  It’s a natural place to be.’
Jowitt pauses to play a sequence from Kung Fu Panda from the Nokia handset. The CGI visuals sparkle and the movie’s multichannel sound design is intense. As a viewing experience derived from a mobile phone it’s kind of unsettling.
JJ: ‘It’s a pretty good clip that one. So, we think that sets a good benchmark for quality. Most mobile TV-to-phone services have been a bit lacklustre. They’ve not whet the appetite of the consumer and I don’t think there’s been a lot of investment into the quality. So we’re hoping this is a bit of a step-changer here in quality for mobile… movies-on-the-go for lack of a better word. It may be a key ingredient that helps people turn that lacklustre section around. I mean, most mobile operators and services offer quite a good music service, but I bet you’d be hard-pushed to find a really good portable movie-based or TV-based service... iPlayer excluded, because the BBC can invest really as much money as they want’.
HCC: Playing Devil’s Advocate, what’s the big difference between what we’ve seen here and what users can download from iTunes?
JJ: ‘iTunes is two-channel, this is high-quality multi-channel. If you buy a show from iTunes it will probably be two-channel with a bit-rate of 192kbps.’
HCC: So this is a huge step-up from AAC?
JJ: ‘It’s a step-change. And you can see why Nokia has embraced it. If you had a white board session with a development team to determine what to put in a phone that Apple doesn’t have, you’d end up with the N8. 5.1 surround sound is the natural tick-box to me. As is the 12MP camera. They’ve included some definite iPhone/iPod-type beating technologies in this device. ‘
HCC: ‘It handles like a cracking portable media player even if you disregard the phone component…
JJ: ‘I think Nokia has done some stunning work on this. When the N8 is not powered up you can connect it to a PC over USB and it’s just like having a USB memory stick plugged in. You can see the memory card, you just can’t see the internal memory of the phone. They’ve just thought about it a little bit more. What does a business man, who becomes a traditional consumer in the evening, what does he actually want to do with his phone? So he needs all of the mail, messaging kind of internet browsing stuff in the day, and on the night he wants to relax a bit more and chill.’
HCC: ‘The big issue going forward is how do you get content onto the phone? That’s the missing part of the proposition.
JJ: ‘That’s very much on Nokia’s agenda, but I can’t obviously give any content partners’ names away at this point because the services are not live. But in conjunction with tools that we have to support this we have a little tool pack called Dolby Media Generator that we’re giving out to content owners and what you might call major mobile delivery aggregator-type companies. They’re taking this toolset to be ready for this and any future devices that might come out on the market’.
HCC: ‘When it comes to Dolby Digital Plus, who else are you talking to? Is this an exclusive technology deal with Nokia in the mobile space?
JJ: ‘We’re probably talking to nearly everybody you could put on a piece of paper. From the very small ones up to…’
HCC: So DDPLus is a big opportunity for the Dolby business’?
JJ: ‘It’s a natural extension of where we are. We’re well-embedded into broadcasts and games, there’s quite a bit in online that you may not even be aware is there, so mobile’s obviously the next stepping stone for us’.
HCC: So what’s the big advantage of DDPlus?
JJ: ‘It’s more efficient and you can have more channels. That would be the two simple strap-lines I would take away. It’s about half as hungry for bandwidth as DD5.1, and you can have many more channels if you want’.
HCC: ‘And there’s no quality compromise even when you reduce the bandwidth as much as you are doing?’
JJ: ‘The bandwidth at 256kbps is what we would recommend for DD+ in 5.1. Now we would recommend 448kbps at Dolby Digital. So you can see there’s a step-change between the two. And there’s a law of diminishing returns. As you get higher and higher bandwidth you can deliver it to less and less people because the pipes get too narrow. So we think it’s more suitable to an on-the-go or portable experience. You’ll find that 256kbps via Wi-Fi is pretty easy to deliver, and then you can put pictures on top of that and it’s still well below a megabit-per-second. But for very high quality full-length movies, the more predictable or reliable method would probably be side-loading.’
HCC: ‘What do you mean by side-loading? 
JJ: ‘It just means copying from your PC or laptop… side-loading is what the iPod has always done. The iPod has always side-loaded. If you think about it there’s no connectivity on the iPod, the only way you put music on it was to plug the Apple cable in. That’s side-loading.’
HCC: This is all well and good, but does a new high-efficiency multichannel standard really bring anything new to the party?
JJ: ‘Bringing multi-channel audio to a portable device like the N8 has actually started to whet the appetite of the music industry, which really did catch us by surprise. We’ve seen a backlash against low-bitrate MP3 from the creators, the musicians and the big name producers; they all say: ‘Isn’t there a better quality out there? And now there is.
Some of the big labels have opened up vaults of 5.1 content to us. They’ve got all this stuff but they’ve never done anything with it, because in many cases releasing it on physical media is not cost effective. But now they’re seeing portable devices come onto the market with 5.1 so they can see a new way of selling high-definition multichannel music. Now I’m not sure where that’s gonna go, but it’s interesting.
HCC: The music industry is always trying to find a way to sell multichannel music…
JJ: ‘Yes, we tried with Super Audio CD ten years ago. But then, didn’t Apple try something called the Newton ten years ago? It’s all about the right time and place. And obviously when somebody as big as Nokia puts out a million devices into the market, it’s seen as a step-change by some of the music labels.
HCC: It’s particularly exciting if they’ve actually got the assets and genuinely want to release them…
JJ: ‘They have, they have. And of course most filmed concerts are captured in 5.1 and if they’re thrown out on terrestrial TV you may not get the benefit of it. We got a list off Universal Music for example, and they’ve estimated they’ve got about 5,000 titles in 5.1. So it’s not a big percentage, it’s not a fifty-fifty split, but it’s still a lot higher than we expected it to be… It’ll be really exciting for older people like me, to be able to go back to stuff that actually was recorded really well and you’ve only ever had it on vinyl or as an MP3, to suddenly think that actually it was always available like this, but they just never sold it to you.
'We’ve done some incredible tests and instead of being sat in the audience watching the band, it’s like you’re on stage. You’ve got the drummer here, the bass player there, it’s like actually being part of it!’
HCC: ‘Long-form music on Blu-ray can be a terrific experience, but the choice has been limited by the expense of actually putting the things out…
JJ: ‘Exactly. Once it becomes an e-format there’s no cost of goods, cost of manufacturing. It could almost herald an era of re-birth for surround sound. We’ve had surround sound for so many years now, but suddenly there are all of these different sources coming, meaning there’s so much more to do with your surround sound system.
'So instead of being limited to shiny disc, they’ve got a phone, potentially broadcast TV, so suddenly there’s all these new ways that you can get this 5.1 material to make your surround sound system really come to life. Hopefully, there will also be all these new people who will think that now is the right time to get a surround sound system.’
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  • The N8 is the first handset in Europe with Dolby Digital Plus.
       
  • Dolby Digital Plus audio tracks down-grade neatly for traditional headphone or speaker use. ('Dolby Headphone tech' isn't used in the N8.
        
  • The N8 will open MKV files (MP4 with multi-channel audio). "The industry is standarising on H.264. The BBC iPlayer HD throws images out in exactly the same MPEG-4 format. So, you can see where this is coming to that central point. The industry is going towards an MPEG container; H.264 720p with a standardised audio stream based around 5.1."
        
  • Jonathan sees the Nokia N8 as hitting many points that Apple hasn't hit yet: "If you had a white board session with a development team to determine what to put in a phone that Apple doesn’t have, you’d end up with the N8. 5.1 surround sound is the natural tick-box to me. As is the 12MP camera. They’ve included some definite iPhone/iPod-type beating technologies in this device."
        
  • DDPlus is "more efficient and you can have more channels. It’s about half as hungry for bandwidth as DD5.1, and you can have many more channels if you want"
        
  • In terms of bandwidth, 256kbps is "what we would recommend for DD+ in 5.1. Now we would recommend 448kbps at Dolby Digital."
        

We're eagerly awaiting the release of the N8 so that we can put all this under our own scrutiny - please Nokia, get the N8 released soon!