The humble pixel – the 2D picture element that has formed the foundation of just about every kind of digital media for the last 50 years – may soon meet its maker. Believe it or not, if a team of British researchers have their way, the pixel, within five short years, will be replaced with… vectors.
If you know about computer graphics, or if you’ve ever edited or drawn an image on your computer, you know that there are two primary ways of storing image data: As a bitmap, or as vectors.
A bitmap is quite simply a giant grid of pixels, with the arrangement and colour of the pixels dictating what the image looks like. Vectors are an entirely different beast: In vector graphics, the image is described as a series of mathematical equations. To draw a bitmap shape you just colour in a block of pixels; with vector graphics, you would describe the shape in terms of height, width, radius, and so on.
These two methods are very different, and they fulfil very different needs. Vector graphics, because they’re made out of geometric primitives, are infinitely scalable, making them the ideal image format for illustrations, clipart, maps, typography, Flash animations, and so on.
For everything else, we use pixel bitmaps. Streaming videos, digital cameras, movie editing, video game textures – all bitmaps. There might be different file formats involved (PNG, MOV, JPG), but they’re all ultimately converted into pixel bitmaps when it comes to displaying them on your monitor, TV, or cinema screen.
Pixel bitmaps have their problems, though. As display (and camera and cinema) resolution increases, so does the number of pixels. The obvious problem with this is that larger bitmaps are computationally more expensive to process, resulting in a slower (or more expensive) workflow.
Pixel bitmaps also don’t scale very gracefully; reduction is okay, but enlargement is a no-no. There is always the issue of a master format, too: With pixel bitmaps, conversions from one format to another, or changing frame rates, is a messy, lossy business.
Which finally leads us back to the innovation at hand: Philip Willis and John Patterson of the University of Bath have devised a video codec that replaces pixel bitmaps with vectors. In a conventional digital camera, images (or videos) are captured as pixel bitmaps and compressed using a codec such as JPEG or H.264. Willis and Patterson have devised a codec called Vectorised Streaming Video (VSV) that converts the bitmap image into vectors. This builds on their previous work with VPI – Vectorised Photographic Images [PDF] – which deals with converting bitmap images into perfect, vectorised copies.
At the moment there’s very little information about VSV, only that the Bath researchers are working with Root6 Technology (a company that specialises in transcoding) and Smoke & Mirrors (a post-processing studio) to bring the codec to market. According to Smoke & Mirrors, there should be working demonstrations of VSV within the next three to six months – and then, within five years, according to the University of Bath, the pixel will simply… die.
Looking at the sample images in the VPI paper (above), Bath’s vectorising algorithm is certainly quite impressive. Performance is awful – but the algorithm is apparently very parallelisable, so this is unlikely to be an insurmountable issue. A brief look through the paper suggests that the algorithm is fairly similar to the auto-vectorisation tools, such as Adobe Live Trace. The biggest issue with photorealistic vector graphics is the colouring of spaces between the geometric shapes – but apparently Willis and Patterson have solved this problem.
Ultimately, though, I think it will take a lot more than a new codec to kill the pixel. There has been no shortage of new codecs over the last few years, but it has so far proved to be very, very difficult to unseat entrenched favourites such as JPEG, GIF, and PNG. Even WebP, which promised to be better than JPEG in every way, failed to gain traction – and that was with the might of Google behind it.
Who knows: A bona fide, high-performance vector video codec would be very, very exciting. If anything could shake up the tools and industry that has built up around the bitmap, it would be a vector video codec, with vector masters that can be scaled and resized infinitely in any direction. “This is a significant breakthrough which will revolutionise the way visual media is produced,” says co-inventor Willis. We shall see.
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