Introduction to DVD Players
With DVDs making so much impact on home video market, the VHS and CD movies are slowly disappearing. There are two things that have made DVD home videos quite popular these days. Firstly, DVDs are truly versatile discs as they can store both standard and high definition movies. This is also true with the modern DVD players that hit the market. You can play CDs as well as DVDs using a DVD player, thus it can replace your old CD player at affordable costs. Secondly, DVDs are designed to offer theatrical experience to the viewers as they are capable of rendering picture in HD format and Dolby sound features.
DVD player - explained
A DVD player, despite having many similarities with a CD player, is designed to play DVDs which use different format or technical standards to store video and audio information. That’s why; a CD player can not play a DVD movie as it is not compatible with the DVD format. However, a standard DVD player can play both CDs and DVDs. In addition, a DVD player can also play MP3 music and can be used for CD-RW. What’s more, the high end DVD players come with additional features like High Definition DVD compatibility and DVD-RW etc.
Generally, a DVD player needs to be connected to TV set and you can find numerous connection options available with modern DVD players. To enhance your viewing experience and to enjoy the DVD resolution, you can connect the DVD player with a HDTV and home theatre system.
For those who are on travel, the portable DVD player is an excellent companion. With an in-built LCD screen, they are light weight and can be taken to anywhere with ease. They have all features of a standard DVD player – high quality output, connection options like composite cable or S-video cable, digital surround system etc.
How does a DVD player work?
A DVD player unit performs following things:
- Reading the data on the DVD disc.
- Decoding the data which is compressed under MPEG-2 method and sending video signals to the output device (like TV set) via S-video, composite, Scart or DVI or HDMI depending on the output device.
- Decoding the sound data and transmitting to speakers using sound decoding systems like DTS.
Reading the data on DVD disc
Like a CD player, a DVD player has a laser unit and rotating spindle to read the data stored on a disc. Since, the pits and tracks are smaller and more closely knitted on a DVD disc, the laser unit in a DVD player uses laser light of short frequency and the high quality lens ensures precise tracking of data on a DVD disc.
Once the disc spins with the help of a motor, the laser head begins to track the data and focus laser on the pits on the disc. The intensity of the reflected light from the disc will vary depending on pits or bumps that were hit by laser light. An electronic device will convert the change in light intensities into digital information.
Encoding & decoding video and audio information
The video and audio formats of a DVD are different. Although a standard DVD has over 4.7 GB storage capacity, a DVD player (with Read Write capability) needs to use video compression method to store a complete movie on a DVD disc. MPEG-2 is the standard compression standard followed by the DVD manufacturers.
To watch a DVD movie, your DVD player will use MPEG-2 decoder to uncompress the data and this process is so fast that you may not notice it.
DVD player decodes the sound in different format like PCM, AC-3 or MP2. All DVD players come with DAC (digital to analog converter) which can provide high quality audio with frequency up to 192 kHz on 24 bit scale.
Interlace scan and progressive scan
DVD players use either interlace or progressive scan method while rendering pictures. Generally, progressive scan produces picture with better resolution and also minimizes flickering. However, DVD players with progressive scanning capacity produce best results with HDTV enabled plasma TVs or LCD TVs which are compatible with high definition standards.
Connecting a DVD player
A DVD player is connected to TV set using separate output and input for video and audio. As for the audio, the co-axial or optical cables are used when your TV set has an in-built Dolby digital surround audio decoder. This option provides excellent digital sound quality.
Another option is to use analog output option (RCA). Two cables from the player are directly connected to the stereo speakers and the sound quality of this connectivity lack digital surround features.
You may also use DTS or Dolby 5.1 which requires six cables to be connected to the input of the receiver. This option can be used as an alternative for co-axial or optical fibre connection in case your TV does not have Dolby digital surround sound decoder.
As for the video component, following methods are used:
- Using composite wires: Just one video cable to connect the DVD player to the receiver.
- Using S-video cable: This option offers much better picture quality as two cables are used for brightness and colour.
- Using component cables: Three video cables are used and offers the best picture quality.
- DVI connection or HDMI: This is used when you connect HDTV to your DVD player.
