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What is the Difference Between DVD and Blu-ray?

Long before the DVD came around there was the VHS. Those of you who are old enough to remember will recall the format: the chunky tapes and the manual rewinding. When the DVD came around it revolutionised the format. Not only were they smaller and more compact, but more data could be stored on the disc, in turn offering better quality. DVDs long reigned (and are still a very popular format), but then it became time to look towards the next high definition format. This was won by a technology called Blu-ray.
If you were to look at a DVD and a Blu-ray then you’d be forgiven for not being able to tell the difference. They do, essentially, look the same. However, it’s what’s on the inside that counts. Blu-ray offers vaster storage and image quality over a DVD. This article will look at the differences between the two disc formats.
A standard, single layer DVD can store around 4.7 GB of data. This is roughly around a two hour movie. Because a lot of films can go on longer, double layer DVDs were introduced and used, offering 8.7 GB of data. This is the reason why, for example, DVD box sets of TV shows are spread across lots of different discs. It just simply isn’t possible to squeeze all the data on the single disc.
On the other side, a single layer Blu-ray disc can store around 25 GB of data. If you were to store standard definition video on the disc (like found on a DVD), then you’d be able to get 13 hours’ worth on it. However, because Blu-ray is a high definition format, the video encoded on the disc is usually produced at a 1080p (or similar) resolution. This higher image quality means that you can store around 2 hours’ worth of HD data on a single layer disc. Double layer Blu-ray discs, on the other hand, hold about 50 GB of data, which is around four and a half hours of HD video.
As mentioned, Blu-ray was a storage device designed to handle high resolution video. An image resolution is, simply, the number of vertical lines times the number of horizontal lines. DVDs usually had a resolution of 480. This was suitable for the older TVs, but when HDTVs were introduced then a DVD could look slightly blurry on such large screens. DVDs could potentially store high definition data, but due to the storage limits it wasn’t worth it.
Blu-rays were designed with 1080 resolutions in mind. Full HD movies can be stored on a disc, meaning that films look crisp and clear when played on any TV set. Those with larger TVs will notice an even greater change due to the vastly superior image resolution.
Fear not, because the upgrade to Blu-ray isn’t as daunting as it might seem. In fact, DVDs are still kicking around and haven’t gone the way of the dodo; VHS, on the other hand, went out of fashion pretty quickly. If you were to buy a Blu-ray player then they are capable of playing DVDs on them too. This means that there’s no need to throw your DVDs away or buy a converter. Just pop them in the disc tray as you normally would. However, having the Blu-ray player also means you have the advantage of being able to buy the new disc format and watch high resolution films if you desire.


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