August 28, 2008 Posted in technology

The HD Jungle – Part 1

Since I bought a HD-Ready LCD TV, I have been wondering how HD movies actually look like in real life. So I decided to connect my old Dell desktop to the TV via an DVI-To-HDMI cable and went to download a couple of those free WMV HD Content Showcase movies from Microsoft.

The next step was to open one of the movies in Windows Media Player 10 and…well, the movie played, but it was more like watching a PowerPoint slideshow. Apparently I overestimated my faithful Dell (a P4 2.6 Ghz with 1 GB of RAM, by the way), since the CPU was already working at 100% of its capacity.

I figured there had to be some way to get some hardware acceleration so that my GeForce 7600 could partially (or maybe even completely) offload the CPU from the movie rendering. And there is where I entered the HD Jungle…

Apparently there are different video encoders/decoders used to compress HD videos, and no real official standard has emerged yet. Also, exploiting your GPU to decode these videos, is not as easy as I thought. To make a long story short, after reading through thousands (?) of forum posts and articles, I think I finally got my head around this HD story. And I thought I would share a summary of my findings.

In this first post, I thought I would try to define some of the basic terms, often carelessly thrown around by manufactures and resellers of TVs and video equipment. In a future posts I will talk about the encoders and file formats used to compress HD videos, followed by a mini-guide about how to enable GPU hardware acceleration on a Windows PC. But first of all, let’s clarify the terminology.

A High Definition (HD) video is a video whose frames have a higher resolution than earlier formats. Typically there is an implicit comparison to DVD-Video that has a resolution of 720×576. HD video, instead, supports one of two resolutions:

720p (1280×720) known as HD ready
1080p or 1080i (1920×1080 progressive or interlaced) known as Full HD

In simple terms, this means that an LCD TV labeled “HD ready”, for example, will have a native resolution of 1280×720, while “Full HD” indicates a resolution of 1920×1080. Also, since all LCD TVs use progressive scan in order to display moving images for technical reasons, “Full HD” usually implies 1080p. This of course applies to all other video equipment, such as cameras and players.

Now, at such high resolutions, digital HD video content usually ends up taking quite a lot of storage space. A typical HD movie of 2 hours, for example, is approximately 5 times larger than the same movie encoded in DVD-Video. This impose the problem of how to store and distribute this content to the masses, since the ~4.7 GB of space available on a DVD disc is no longer enough. A new standard optical storage format for the media industry was needed.

Two contenders emerged to fight for the title of “successor of the DVD disc”:

HD-DVD with a capacity of ~15 GB
Blue-ray with a capacity of ~25 GB

HD-DVD and Blue-ray were backed up by different manufacturing and retail companies. Most remarkable is probably the case of Microsoft offering an external HD-DVD player for the Xbox 360, while Sony’s PlayStation 3 came with its own Blue-ray player. This meant that during a 2-year period, commercial video content (movies and video games) were delivered in both formats, leaving the choice to consumers on which format to support when buying hardware. In 2008, however, two big supporters of the HD-DVD format (Warner Bros. and Toshiba) suddenly switched side, practically declaring Blue-ray the winner of the “format war”.

This concludes the first of three posts on the “HD Jungle”. I hope this information is as useful to you as it is to me.

/Enrico

Enrico Campidoglio

Hi, I'm Enrico Campidoglio. I'm a freelance programmer, trainer and mentor focusing on helping teams develop software better. I write this blog because I love sharing stories about the things I know. You can read more about me here, if you like.

The HD Jungle – Part 1

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Enrico Campidoglio