What is HD?
What is HD?
If I want to create a HD porn player on the cheap then I'd better start by understanding exactly what is meant by HD. So I did some digging and this is what I found...
A HDTV (High Definition Television) is a TV that is capable of viewing video signals at a higher resolution than standard TV or DVD. That means it can play HD channels broadcast over cable or satellite (in the UK at least) and HD movies from dedicated HD players such as Blue Ray players.
So far, so good. But as I looked further I found that there's more than one screen resolution that can be called HD. In fact, there are three main resolutions to be aware of. They are known as 720p, 1080i and 1080p. I will try to explain the differences...
A TV or computer screen is made up of thousands of tiny coloured dots called pixels. The 720 and 1080 in HD represents the number of lines (rows of pixels) that are used to make up the picture. So 1080 is higher resolution than 720. However, the ‘p' (progressive) and ‘i' (interlaced) make a difference. Without going into too much detail an interlaced video only takes up half the data of a progressive video and is therefore lower quality. The net result is that 720p and 1080i are roughly similar quality whilst 1080p is currently the top of the range in HD.
Do I care about interlaced video?
Interlaced video was designed for traditional (CRT) TV sets. Computer displays and LCD TVs cannot play interlaced video; instead it must be converted (de-interlaced) into a progressive form. Although interlaced formats are used by some broadcasters, so far I've only seen progressive formats (720p and 1080p) offered for download on porn sites. I suspect that will be the case even for streamed video on the net. So, no, I don't really care about interlaced video :)
Next time I'll go into more detail about screen sizes and resolution.
Bye for now :)