Buying guide: DVD player

Benefits of a DVD player

Since the last decade or so, a portable DVD player along with the ubiquitous DVD has managed to become a necessary part of an entertainment setup in most households across the world. Even though the DVD is similarly sized as a normal CD, it features higher storage capacity allowing more data to be stored on it and subsequently more entertainment to be had. A single sided, single layer DVD stores 4.5 Gigabytes (GB) of content, while a double layered, double density DVD can hold up to 17 GB of data. This extremely high storage capacity allows up to five full-length movies to be stored on a single DVD including footage of the shooting duration, behind the scenes facts of movies, and even interviews with the director and its stars - a delight for any movie fan or collector. A home DVD player allows you to watch movies at a stretch within the comforts of your home.

A recent development includes DV players featuring a built-in LCD display screen that allows you the convenience of watching movies at any place and at anytime even when on the move; car DVD player is a fine example. Majority of DVD players are backward compatible for playing audio CDs, and even older Video CDs (VCDs) standard discs.

How do DVD players work?

For understanding as to how DVD players operate, we first need to familiarize ourselves with the DVD media from which data is read and how such data is written onto a DVD. A DVD is similar in diameter and thickness to a conventional CD, and is also manufactured using the same materials, which are multiple layers of polycarbonate plastic. On a DVD, data is written or rather burnt in as miniscule bumps or pits consecutively as a single spiraling track beginning from the center of the disc radiating towards its outer edge, on each layer. Subsequently, a thin reflective material is spread across its first layer, aluminum being used underneath the initial layers, and reflective gold film sprayed on its outer layers. This technique allows the laser-based reading head of the DVD player to read data on the inner layers. After finalization of all layers, each layer is exposed to infrared light after acquiring a varnish of lacquer. Hereafter, a label of the DVD is printed. The label is printed on the non-readable side of single sided discs, whereas the label is printed on the small non-readable region near the center orifice in double sided discs.

When a DVD is slipped inside a DVD player, a laser beam is aimed onto its surface for reading the bumps and pits. The video data, usually encoded using the Moving Picture Expert Group 2 (MPEG-2) video compression standard, is then decoded into a reproducible video signal for playback on TV sets. Moreover, the audio stream is passed in parallel through a Dolby or a DTS decoder, and channeled to amplifier unit, and finally to the speakers.

Considering the microscopically small-sized audio and video data (spiraling) track, which has a pitch of approximately 700 nanometers, and the length of the ‘bump’ or ‘pit’ approximately 440 nanometers, it is inherent that the reading head of the DVD player is significantly sensitive. This allows precise collaboration between the three key components mentioned below:

1. 1.    The drive motor: A motor, with varying rotational speeds between 200 to 500 rpm (depending on the track being read), rotates the DVD disc.

1. 2.    The lens and laser apparatus: The laser emitter focuses a light beam with a wavelength of around 640 nanometers, which enables the laser reading tiniest bumps and pits.

1. 3.    The tracking assembly: The apparatus moves the laser assembly along the spiral track of the DVD. This motion occurs in increments of few microns at a time.

Let us glance at how DVD data is unscrambled by a DVD player. A laser beam bypasses the DVD’s polycarbonate layer, gets reflected from the reflective layer underneath and is detected by an opto-electronic mechanism that is sensitive to variations in the laser’s intensity. The variations are picked up in the light reflected from the surface. The variable light readings are then transformed into digital format comprising of only binary numbers that is, 0 and 1.

For easy shifting of the laser mechanism, DVDs that comprise a second layer, have the secondary data track beginning from the edge of the disc, and working towards the center. As a result, the laser head starts reading the bumps and pits contiguously after reaching the end or edge on the first layer, without requiring to move towards the center again.

Also, another important thing to understand is the intrinsic region code feature that offer regional limitation for the playback of DVDs. The region codes prevent unauthorized viewing or copying of video DVDs. Hence, DVDs with a certain region code cannot be viewed on DVD players manufactured in another region. These days, you can get DVDs that are multi-region capable and can be viewed on any region DVDs. Also, DVDs can be modified to feature playback compatibility with DVDs from all regions.

Purchasing criteria 

Choosing the player you want from a wide range of DVD players that have flooded the market today is a time consuming and tedious process. We are listing some key parameters for you to keep in mind while purchasing a new DVD player:

1. Multi region compatibility: As explained above, the multi region compatibility is one of the most important parameters to be considered before buying a DVD player. The safest bet is a multi-region DVD player, which ensures no DVD bought or hired goes unviewed due to incompatibility. If you are a frequent traveler, or you have friends or relatives in foreign countries that may send you DVDs, it becomes even more important to go in for such a DVD player.

1. Single disc player or multi disc player: A single disc DVD player can playback only one DVD at a time. Whereas a multi-disc DVD player can provide for storing up to hundreds of discs simultaneously. For a regular home viewing, a single disc, or a 2- or 3- disc changer DVD player suffices. The multi-disc DVD players with greater disc storage capacities are usually used as DVD jukeboxes, in restaurants, lounge bars, coffee shops, and other public places.

1. DVD players with the LCD screen: For users who plan to use DVD players outdoors or while traveling, a DVD player with a built-in screen of approximately 10 inches or more is highly recommended. Most of the DVD players designed for use in computers function as a DVD recorder as well.

1. Compatibility with your television: Prior to acquiring a DVD player, ensure that the DVD player is compatible (or backward compatible) with your television (TV) set, depending on the types of provided connectivity options. Few of the commonly featured input ports are listed hereunder:

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   1. S-video: A Separate video (S-video) output connector splits the video data into two separate analog signals providing better clarity and color reproduction.

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   1. Composite video: Composite connectors facilitate transmitting analog signals between the TV set and gadgets such as a game console, video cassette player, as well as the DVD player. Its three-pronged cable comprises a yellow female RCA jack for video signals, and two red and white audio female RCA jacks for transmitting stereo audio signals to the television set.

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   1. Component video: This connection standard guarantees superior quality output. If a television set features this input, it is recommended to opt for a DVD player sporting Component video outputs. Component video connectors have three RCA jacks — red, green, and blue colored plugs for video and stereo output, just like the Composite video cable.

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   1. Coaxial digital output: This connector is developed for reproduction of higher quality audio output, and is a must-have if you happen to already own a Dolby Digital receiver.

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   1. Stereo output: This is a general connector pertinent to television sets featuring only two stereo speaker units.

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   1. 5.1 channel output: Employing the Dolby Digital technology that offers 5 full-bandwidth audio channels, namely the front left, front right, middle, surround left, and surround right this output connector provides true-to-life surround sound reproduction for an immersive audio experience. The low frequency bass output is directed to a dedicated subwoofer. DVD players that can decode 5.1-channel encoded video DVDs, must feature a special built-in Dolby Digital decoder unit as well as a dedicated digital to analog (DAC) for transforming digital output to an analog signal for transmitting to an analog amplifier unit.

1. Remote control: Importantly, any remote control should be very user-friendly device with the capability to control the DVD player from any corner of the room. Virtually, all the functions of the system can be adjusted using the bundled remote control.

1. Size: The size and shape of the DVD player must also be considered prior to purchasing one after examining the space available to place your DVD player, as well as whether the device would be frequently ported around the house or would be used as a stationary unit.

Making a decision

There are plenty of options when it comes to DVD player models; Sony DVD player, Panasonic DVD player, and Pioneer DVD players among the prominent ones. Upon investigating your requirements, preferences, and considering the various attributes mentioned above, compare various DVD players available across the market, which comply with your requirements. DVD players offer one-stop entertainment platform and hence it is highly recommended that one meticulously inspects each and every feature of DVD players across different brands before selecting one. If possible, also counsel contacts who own such devices, and then arrive upon a decision.

Another key consideration while buying a DVD player or for that matter, any electronic device is the after-sales service and warranty offered by the manufacturer. We also advocate reading the instruction manual thoroughly (if provided before purchasing) as maintenance and usage of such gadgets is crucial to ensure long-life and trouble-free operation.