TV on your cell phone in Japan - OneSeg · 2006-05-03 19:35 by Damian
Ever heard the word OneSeg? Or perhaps WanSegu? If you don’t live in Japan, probably not. In fact, most Japanese people don’t know it either. So what is it? As you would probably not be able to guess from hearing it, it’s all about watching TV on your cell phone. The service launched on April 1st here, so how does it look one month later?
Introduction
First of all – why the name OneSeg? It simply means “One Segment”, which in turn means that one segment of each channel used for digital terrestrial TV broadcasts is reserved for portable devices.
Not the world’s best acronym, but really – the meaning of competing standards DMB (Korea) and DVB-H (Europe) are not that obvious either. While these three standards are rather different, the share the same design criteria:
- Allow for low-power receivers, to provide decent battery life
- Allow for efficient spectrum utilization, i.e. use low-bitrate codecs
- Allow for proper reception in high-speed vehicles
DMB is already in commercial use in Korea, DVH-H are running several trials thoughout the world, and Japan launched the service in selected parts of the country on April 1st.
So does it work?
Well, keeping in mind that the products out right now are first generation, it looks pretty good. There are cell phones with built-in OneSeg tuners available from NTT Docomo as well as au/KDDI, but they are fairly bulky. They have rather clumsy external antennae that can be deployed for better TV reception, which is needed especially if you are indoors.
Cell phones with analog TV tuners have been available for quite some time in Japan, though they’ve never gained significant popularity. A big reason for this has probably been the fact that they are a bit too bulky, and provide abysmal battery life – you would drain a freshly charged battery in about an hour watching analog TV.
This is where the improvements of digital transmission are most obvious – the new cell phones (remember, first generation) offer around three hours viewing. This is simply because with the transmission encoding used, the radio receiver does not need to be switched on all the time, data arrives in pre-determined timeslots. While this is somewhat counteracted by the need for more power-hungry decoding, a three-fold increase in battery life is still quite substantial.
New Sony laptops also offer a built-in OneSeg tuner as option, and there have been announcements of external tuners for normal PC’s, though they have yet to be commercially available.
Any disadvantages?
Like all systems that use low-bitrate codecs such as H.264, you will end up with channel switching times that are very noticeable. This is due to the different use of I-frames – the complete pictures that are needed to start decoding at a random point of a stream. Legacy MPEG-2 typically uses 2 I-frames/second, meaning that we may need to wait for up to 0.5 seconds just to find a point where we can start decoding. While this is manageable, in low-bitrate codecs, the distance between I-frames can easily be several seconds depending on which encoding parameters are used. Accordingly, changing channels takes a few seconds, so you won’t be doing any quick channel zapping.
Final words
TV in your cell phone – would you use it? At the moment, the programs available are the same as normal broadcasts, which is npt optimal. Portable devices have smaller screens, and they are certainly used differently. You don’t have time to watch a full-length movie or even a 1-hour episode of a normal series while you’re waiting for the train. There’s no time, and it would be rather tiring to watch on a small screen.
Once dedicated programming starts to appear, thing will look different. I can imagine news, sports and short episodes of soap operas etc could get really popular.
However, the cell phone operators do not quite know how to handle the business either, the broadcasts do not use the operators’ networks, so there’s no revenue there. Instead they are trying to add interactive features to programs, you’ll get links to web pages related to what’s currently showing and things like that. This will provide some revenue from data transmission, and if bundled correctly could work out really well.
That’s all for today, Golden Week continues… :)
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