Blu-ray’s extra storage capacity allows the technology to store much more information and so offer significant advantages in picture and sound quality over DVD.

The big disappointment with Blu-ray, of course, is that most discs are region zoned (Australia is zone B). If you import discs unavailable in Australia you will probably find they will not play on Australian Blu-ray players. Some discs are not region coded and will play on all players.

The most obvious difference between DVD and Blu-ray is the resolution or number of pixels. The DVD format is 576i or 576p which is 576 horizontal rows each containing 720 pixels for a total of 414,720 pixels. The DVD image (PAL, which is the Australian and European standard) has a frame rate of 25 frames per second. 576i is refreshed 50 times per second. The first refresh displays the odd numbered horizontal rows of pixels (rows 1, 3, 5 through to row 575). The next refresh displays the even rows of pixels (rows 2, 4, 6 through to row 576) then odd, then even etc. Because the image is interlaced it takes two refreshes per frame, so 50 refreshes per second are required to display 25 frames per second. 576p refreshes 25 times per second; being progressive, the complete image is refreshed each time so that 25 frames requires 25 refreshes. The US standard “NTSC” is 480i or 480p with a frame rate of 30 frames per second. If interlaced the image refreshes 60 times per second while the progressive image refreshes 30 times per second.

The Blu-ray format is 1080P which is 1,080 horizontal lines each containing 1,920 pixels for a total of 2,073,600 pixels. The image is refreshed 24 times per second, which coincides with standard film shot at 24 frames per second. As the image is progressive not interlaced the complete image is displayed at each refresh rather than half the image twice as often. If the equipment being used does not support 24 frames per second it will use the standard Pal refresh rate of 25 times per second. The reproduction (film) speed will then be increased by just over 4%.

The image from Blu-ray will be much sharper and more detailed than DVD because of the increased resolution (five times) and the fact that Blu-ray is almost always progressive while most DVDs are interlaced. When projected onto a large screen the improvement in image quality is obvious. Even moderately priced 1080P projectors combined with Blu-ray display sharpness and detail we could only dream about a few years ago.

I remember using a high quality Davis projector and tripler at an audio show some years back; a combination which sold for around $40,000 at the time. To-day, using Blu-ray as a source, a 1080P projector worth around $4,000 would blow the socks off the Davis combination while costing only a tenth the price.