Back in the days of reel-to-reel tape and tape hiss interfering with high frequency sound, Dolby Labs made a name for itself with Dolby Noise Reduction, which recorded high frequencies at a higher volume and played them back with an equivalent amount of volume decrease to reduce the impact of tape hiss. Now Dolby wants to do the same kind of thing to television.
Dolby Noise Reduction
Dolby Type A noise reduction was introduced in 1966 for reel-to-reel tape recorders. Reel-to-reel tape was 1/4″ wide and normally moves at 3-3/4″ (9.5 cm) or 7-1/2″ (19 cm) per second (IPS). Studio recording was typically done at 15 IPS (38 cm/s), and 1-7/8 IPS (4.76 cm/s) was often used for long speeches where high-end audio quality didn’t matter. Radio stations often used 15/16 IPS (2.38 cm/s) for archival broadcast logs to conserve tape, and those who needed the ultimate high-end quality could choose 30 IPS (76.2 cm/s) on some premium recorders.
The lower the recording speed, the more hiss there was at high frequencies. Dolby Type A noise reduction was designed to work best at the most commonly used reel-to-reel speeds of 3.75 and 7.5 IPS. Dolby A can reduce tape noise by up to 15 dB.
The Compact Cassette, introduced in 1963, can be used in both directions and normally records at 1.875 IPS on 0.15″ wide tape – only 60% as wide as reel-to-reel. Between a narrower tape with much narrower tracks (two tracks on mono recorders, four with stereo gear) and the slow speed, quality sound called for a different type of noise reduction. With the popularity of the cassette tape, Dolby introduced Type B noise reduction, which can reduce hiss by up to 10 dB.
Dolby B became a standard feature of stereo cassette recorders and players in the 1970s, and when used with high-bias tape, it sounded pretty good – especially in your car stereo, where road and engine noise masked what little hiss remained.
Dolby Labs improved that with Dolby Type C, which can reduce tape hiss by up to 20 dB. Dolby C came to cassette tape recorders starting in 1981. In 1982, the first CD players came to market, and over time CDs replaced cassette tapes in home stereo systems and car audio systems, marginalizing all of this Dolby noise reduction technology.
Dolby at the Movies
Stereo Comes to Movies
Modern stereo sound began in movie theaters in the 1930s thanks to Alan Blumlein, who found it disconcerting to hear sound coming from a single speaker when an actor was one one side of the screen or the other. He developed his ideas and applied for a patent in 1931. His first experiments took place in 1933, and he released test films in 1935 where the sound followed an actor or train as it went from one side of the screen to the other.
Disney’s original Fantasia, released in 1940, used 3-channel stereo (right, left, and center channels) plus surround sound to have a bumblebee fly around the studio, although “Fantasound” was absent in later releases. Stereo didn’t become a staple in movie theaters until Cinerama arrived in 1952.
In 1969, home audio entered the Quadraphonic era with 4-channel reel-to-reel decks and audio systems that placed a speaker in each corner of a room. In 1970, Quad-8 came to the 8-track tape. Competing formats on vinyl included EV-4, Dynaquad, QS, SQ, Quadradisc, and UD-4, and the lack of a standard hurt adoption of Quadrophonic systems. With several competing 4-channel standards and the expense of four matching speakers, Quadrophonic audio – spectacular as it could be at times – never caught on.
Dolby and Movies
Stanley Kubrick’s A Clockwork Orange, released in 1971, was the first movie to use Dolby noise reduction, and Star Wars was the first movie in Dolby Stereo, bringing a new sound experience to moviegoers around the world by optically recording right channel, left channel, center channel, and a surround channel with the movie. Dolby Stereo wasn’t the first multitrack audio system, but it was the first to work well and earn widespread adoption.
Dolby and Television
In 1982, Dolby Labs introduced Dolby Surround for use with video recordings. The original version used a two-channel recording system, but with a Dolby Surround decoder, a surround channel could be created at home. However, the center channel used by Dolby Stereo was not included.
Batman Returns, released in Summer 1992 and the second Batman film by Tim Burton, was the first movie with a Dolby Digital soundtrack. The soundtrack uses five speakers (front right, left, and center plus left and right rear) plus a subwoofer; this format is commonly called 5.1 audio.
The first HDTV broadcasts with 5.1 Dolby Digital sound came in 1998.
Dolby Digital Surround EX was jointly developed by Dolby Labs and Lucasfilm THX. It add a rear center speaker and debuted with Star Wars Episode 1: The Phantom Menace in May 1999. Dolby Digital Plus allows for up to 13 audio channels plus a subwoofer; anything 7.1 to 13.1 used Dolby Digital Plus.
In 2012, the Dolby Theatre opened in Hollywood as a showplace for the latest Dolby technology. Dolby Atmos was also introduced in 2012 as a new sound standard for cinema, home use, and personal audio.
Why Dolby Vision?
Dolby Noise Reduction addressed the issue of hiss when recording to audio tape, which also came to benefit the soundtrack of movies. Dolby Stereo addressed the limitations of 1-, 2-, and 3-channel sound used in movie theaters and made 5.1 surround sound the norm for movies. Dolby Surround brings the same things to home entertainment.
Dolby Vision addresses some things most of us never thought of:
- current digital technology works with a very limited color palette
- current TV displays don’t have the brightness range needed to mimic reality
The promise of Dolby Vision is brighter, more detailed brights; darker, more detailed shadows; and richer, more accurate color that we’ve ever seen on a digital display.
What Dolby Vision does is similar to HDR (high dynamic range) photography, which improves detail in bright and dark regions of your photos. HDR does this by intelligently remapping an expanded brightness range to the 24-bit range used for JPEGs and standard photography.
But Dolby Vision turns this on its head. Instead of compressing an expanded brightness range to a 24-bit display, Dolby Vision uses more data to more accurately record colors and brightness. The example below attempts to translate that to an image we can display on our 24-bit displays:
Dolby Vision is going to change everything. New cameras will be developed to record the extended brightness range Dolby Vision is capable of displaying. New television screens will be developed to display a much greater dynamic range than today’s 24-bit screens. And we’ll need better ways to share Dolby Vision videos that go beyond the range of Blu-ray.
There are three possibilities to improve television, and they are not mutually exclusive:
- More pixels. DVD is better than VHS. Blu-ray is better than DVD. 4K is better than 1080p, which is better than 720p.
- A higher frame rate. Movies have traditionally been filmed at 24 frames per second (FPS).
- Better pixels.
More pixels is obvious. If you’ve ever watch 18 fps Super 8 films, you know how bad a low frame rate can be, but the industry is only now experimenting with higher frame rates, such as the 48p used in The Hobbit: An Unexpected Journey. Some viewers have complained that 48p is too realistic, so time will tell if it catches on.
Dolby wants to give us better pixels, pixels with more dynamic range and more accurate color than a 24-bit system can create.
Brightness is measures in nits, and the Dolby Vision White Paper (PDF) explains how an outdoor scene may contain light ranging from 145 nits to 14,700 nits – a dynamic range of over 1000:1. Your TV limits the brightness range it can display to 0.117 nits for its darkest black to 100 nits at the brightest, limitations shared by Blu-ray and those old CRT TVs we used to watch before flat screen TVs became popular.
Ultimately Dolby wants to be able to record a brightness range from 0.0001 nit to 10,000 nits, and Dolby Vision hopes to see home displays capable of displaying from 0.003 nit to 1,000 nits. That’s 40 times as much shadow detail and 10 times as much brightness as today’s TV sets. As a result, we should see more saturated, more accurate color on displays with Dolby Vision.
Early Steps into Dolby Vision
The key to Dolby Vision is recording images in PQ space, which is more attuned to our perceptual abilities than current video standards. Cameras will need to be able to work with a much more extended dynamic range than today’s 24-bit color.
Dolby already makes mastering displays that support a brightness of roughly 3,000 nits, so video editors have the displays they need to work accurately with this broad dynamic range.
Most modern game engines should be capable of being extended to support to broader range of Dolby Vision, although this will mean new hardware for the gamer.
Content can be sent out over the Internet, and both Netflix and Vudu already support Dolby Vision. Dolby Labs is working with the Blu-ray Disc Association and other organizations to make sure Dolby Vision can be used with their standards.
What’s Available Now?
Dolby Vision was unveiled two years ago and had a big presence at the Consumer Electronics Show earlier this month. Several manufacturers have announced TVs that will work with Dolby Vision, but right now content is limited to:
- Marco Polo on Netflix
- The Revenant
When it release on April 15, 2016, The Jungle Book will join them. Universal, Warner Bros., MGM, and Sony are also on board with Dolby Vision.
For TVs, TCL, Vizio, and LG are adopting Dolby Vision for their OLED sets. Sony hasn’t announced a Dolby Vision set but is working with Dolby on a 4K Dolby Vision television.
What’s the Competition?
The competing standard is Ultra HD Premium, being pushed under the HDR 10 name. Where standard video used 8 bits per channel for 24-bit video, HDR 10 extends that to – drum roll – 10 bits per channel and 30-bit output.
Regular TV stops at 100 nits, HDR 10 supports 1,000 nits, and Dolby Vision beats both with 4,000 nits.
Best of all for consumers, anything that supports Dolby Vision should also be compatible with HDR 10, so even if Dolby Vision doesn’t catch on, you’ll have the next best thing.
What Does It Mean for Me?
After reading the online reviews and comparisons, especially from those who attended the January 2016 CES, to consensus seems to be that 4K is going to take a back seat to brighter TVs. Of course the ultimate with be 4K sets with Dolby Vision, but the impact of Dolby Vision is far more impressive than just having more pixels on the screen.
As for improving dynamic range, HDR 10 is simply adding four more levels of brightness. Dolby Vision is changing the way equipment encodes and decodes images to off a far more extended range of brightness and color.
In the final analysis, most of us buy a TV and use it for years and years. I tend to stick with a technology until it no longer satisfies me. I bought my television on close-out when $700 was a good price for a 42″ 1080p TV. At the same time I bought a DVD player that intelligently up-samples to 1080p so my DVD collection can look its best. I don’t have a smart TV. I don’t have Blu-ray. I do have still good enough.
My advice is not to jump on the Dolby Vision or HDR 10 bandwagon too quickly. Remember how many people got burned when they chose HD DVD over Blu-ray in 2006 and 2007? Toshiba, Sanyo, NEC, Intel, Microsoft, and HP were pushing HD DVD; how could it fail? Universal and Warner Bros. were providing content; it had to win!
Wrong. Warner Bros. announced on January 4, 2008 that it was pulling the plug on HD DVD. Then Netflix phased out HD DVD offerings. And then Best Buy made a corporate decision to promote Blu-ray over HD DVD. And when Walmart announced it was going Blu-ray only, that was it. On February 19, 2008, Toshiba announced it was going to discontinue its HD DVD hardware.
I have no idea how quickly or how slowly Dolby Vision is going to ramp up, but new technologies usually start on the most expensive hardware and trickle down to the masses. And then there are issues like network content, studios releasing content in the new format, gaming consoles gain support, and so on. The longer you can wait to buy a set with HDR 10 or Dolby Vision, the less you’re going to pay for it and the more options you’ll have.
When you buy your next TV, check where the industry is going. If HDR 10 and Dolby Vision are neck-and-neck, a Dolby Vision TV will give you both.
Me? I’m going to be content with my perfectly adequate TV until it dies or until something so superior comes out at a price that I can afford that it’s time to make the jump.
- Dolby Vision on TV: Should Your Next TV Have Dolby Vision?, 2016.01.13, John Archer and Andy Vandervell, Trusted Reviews
- Dolby Has a Better Vision for the Future of TV, 2015.01.09, Bryan Bishop, The Verge
- How Dolby Vision Works, and How It Could Revolutionize TVs Forever, 2014.06.24, Andrew Tarantola, Gizmodo.
Keywords: #dolbyvision #hdr10 #hdrtelevision
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