Posts
How HDTV Works
Learn How HDTV Works in the USA and how it is expanding to other countries.
Although the technology that is in fashion this year and will sell more this Christmas is DTT, Digital Terrestrial Television, we can already begin to prepare for who will fashionable next year, HDTV, TV High Definition. Although we already have plenty of available products compatible with HDTV, probably the next-generation consoles will be those that will make this technology take off definitively in our country.
Specifications of HDTV
The most important feature is the highest definition picture offered by HDTV compared with current systems. If the PAL system used in Spain offers a resolution of 768 x 576 pixels, the HDTV can use two different resolutions: 1920 × 1080 and 1280 x 720 pixels, always using the ratio 16:9.
These high resolutions are achieved by sending the signal through a compressed codec as MPEG-2 or H.264. The sound is transmitted with Dolby Digital 5.1 and offers to take advantage of the popular speaker systems of Home Theater.
HDTV resolutions
Differences between 1080i and 720p
Many among you have seen the features of the XBox 360, that supports two different output resolutions: 1080i and 720p. These resolutions are the two we have commented that offers HDTV and indicate the number of lines that can be seen. The i indicates that the signal is interlaced, meaning that in every single frame is drawn half of the lines of the screen (a yes and no), ie 540 lines are displayed every time, switching alternatively. By repeating this process many times and very quickly our brain is able to decode it and we can properly view the images.
The p, in contrast, means progressive, and indicates that all the lines are drawn in the image, one after the other.
Which is better? The theme is a bit subjective, but is recommended for the 1080i images with little movement or movements slow and fast movements that can distort the picture. In return, this resolution provides more detail and a better image.
In contrast, the 720p is more suited to rapid camera movements. For example, in U.S. chains ABC and ESPN use 720p format because it offers better results in their broadcasts of sporting events, where the cameras often have to move at high speed.
How do HDTV Work?
As we commented in our colleague Javier special DTT, this is not the way to see HDTV, as the DTT (at least in the USA) does not provide the bandwidth needed for transmission in high definition across the country at least not yet.
Therefore, most systems will be to see HDTV cable and satellite. In the case of Spain, Digital Plus was doing tests in HD transmission via satellite, while DirectTV intends to deliver through the platform they offer ADSL 2.
Of course, you need a TV that supports this resolution, although many of the new models are already beginning to bear it is advisable to check that the TV that has a buy a HDMI (High Digital Multimedia Interface).
It seems quite doubtful that in the near future we can start watching high-definition television in the USA, at least in a generalized way. For now, the chains are focusing on the transition to DTV and not taking into account the potential of HDTV, so you spend a few years before the system is introduced. At least, we can use our consoles to take advantage of the formats offered by the new televisions.
