FIRST QUESTION - WHAT IS A UNIVERSAL DVD PLAYER?
Very strictly speaking, a standard DVD has just two sets of data inside. One is the video compressed using MPEG-2 and the other is audio that, in its simplest form, has been encoded using DTS or Dolby Digital. Again strictly speaking, a non-universal DVD player is not supposed to play another other type of media.
Secondly DVD come in various capacities:
Single-sided/single-layer 4.38 GB 2 hours (DVD-5)
Single-sided/double-layer 7.95 GB 4 hours (DVD-9)
Double-sided/single-layer 8.75 GB 4.5 hours (DVD-10)
Double-sided/double-layer 15.9 GB Over 8 hours (DVD-18)
There was also for a short time a DVD-14 which does not exist anymore. This had two sides, with single layer on one side, and double layer on another.
What has happened in the recent past is that DVDs have taken on many forms. There are DVD, DVD-9, DVD-18, DiVX. DiVx is a video encoding technology, released by company called DivXNetworks that came about as an open source competition to Microsoft's MPEG-4 codec. Because of the higher compression ratio as compared to MPEG-2, DivX can store multiple movies on a single DVD.
In addition to movies, there are DVDs that store only audio.
There is the
Super Audio CD (referred to as SACD).
Developed by Sony and Philips, an SACD is capable of capturing sound up to 100kHz using sampling up to 2800kHz (2.8 MHz). A CD can only handle up to 44.1kHz. An SACD has the same capacity as a DVD-5, about 4.7GB and 8x the capacity of a regular CD. Using Direct Stream Digital (DsD), the music can be delivered either as 2.0 stereo or via 5.1 channels with no loss in quality. DsD also removed the need for Delta-Sigma modulation and Decimation and Interpolation filters which means the music you hear from an SACD is as natural as possible.
Then there is
DVD-A, usually referred to as DVD-A.
DVD-Audio is one of the standards controlled by DVD Forum, an authority behind various DVD standards. DVD-Audio is audio only, aimed to replace regular audio CD within next few years. Audio can be stored in various formats, including uncompressed (L)PCM format (in frequencies from 44.1kHz upto 192kHz) with bitrates as high as 9.8Mbit/sec. Other formats allowed include Dolby Digital 5.1, MPEG-1 (stereo, audio layers II and III), MPEG-2 (multichannel), DTS and SDDS.
An universal DVD playe is supposed to play ALL these format of DVDs and a standard audio CD also !!! Current DVD players may not necessarily play anything more than DVD-9 unless specified by the manufacturer.
Universal DVD players have a set of 6-channel analog audio outputs that allow the consumer to access SACD and DVD-Audio on an AV receiver that also a set 6-channel analog audio inputs.
Due to differences in the way SACD and DVD-Audio signals are encoded on a disc, the DVD player must convert the signal to an analog form as digital audio connections on a DVD player that are used for access Dolby Digital and DTS audio are not compatible with SACD or DVD-Audio signals.
SECOND QUESTION - WHICH DVD PLAYER TO BUY?
Logically speaking, any good Universal Player will suffice IF you have a good AVR. For example, if you have an high end AVR from Denon, Yamaha, Onkyo, NAD, or CA that can decode all audio codecs, and also upscale the video to 1080p, it would be sufficient to buy a decent Universal DVD player costing around Rs.5000. Remember both the DVD player and AVR must support HDMI. You will see why down below.
Many AVRs do not support multi channel Linear PCM (7.1 ch 32-192KHz), but can accept the standard Dobly, DTS and other video related audio signals through bitstream. These signals can be sent to the AVR mostly though coaxial or optical digital connection. When you send the signal in digital form, the AVR does the decoding including DAC conversion.
Till now everything is fine. But what happens when multi channel Linear PCM is not supported by the AVR? We will expect the DVD player to do the decoding and output the signal in analogue form. Thus slighly high end universal DVD players will have 6 to 8 analogue audio outputs. Most AVRs will have a minimum of six corresponding audio-in to just amplify these signals.
For an AVR to do all these, you need one that supports Multi Channel linear PCM, and has a HDMI input. Multichannel linear PCM CANNOT be transmitted through coaxial or optical digital connections.
DVD Players that do perform audio decoding will have DSP chips with a minimum specification of 192 KHz at 24 bits (usually referred to as 192/24) made by companies such as Cirrus Logic, Burr Brown, Analog Audio, etc.
There are couple of other things to keep in mind when buying DVD Players. In most players, the actual mechanical part that holds and plays the DVD is made by companies such as Sony or TEAC. The DVD player manufacturer adds value in designing the PCB, and the electronics needed for audio and video decoding. In addition they ensure high quality connectors as well as good power supply units to make sure the player functions well. See he following link for more information on power supplies.
http://www.hifivision.com/audio-vid...own-transformer-affect-hifis-performance.html
Very low priced DVD Players will use cheap mechanisms from China and save money on the decoding electronics. Remember if the DVD player outputs trash as video and audio, your poor AVR wil amplify just that- TRASH.