A Guide to DVD-Audio and DualDisc

[Big Daddy]

For additional information, check my threads on SACD and DSD and Home Theater Audio CODECs.

A GUIDE TO DVD-AUDIO (DVD-A) AND DUALDISC

Prepared by Big Daddy

What is DVD-A?
DVD-A is not a home theater audio CODEC. It is a format developed by DVD Forum (as an alternative to SACD) to use the vast storage available on a DVD for high resolution and multi-channel music. The first DVD-A discs appeared in 2000.

In addition to audio, a DVD-Audio disc can contain video, lyrics, notes, or pictures. As an option, a DVD-Audio disc can also include audio recorded in Dolby Digital and DTS digital for compatibility with standard DVD players. Almost all the DVD-A and standard DVD players can play back the video content. However, DVD-A players will only recognize the PCM DVD-A tracks and will not play the DD or DTS tracks.

http://en.wikipedia.org/wiki/DVD-Audio
http://www.dvd-audioworld.com/home.htm#
http://www.timefordvd.com/tutorial/D...Tutorial.shtml
http://firstdtsstudio.hit.bg/faq_dvda_eng.html

Is the Sound Quality of DVD-A Better than CD?
Yes, DVD-A uses a high resolution and lossless coding format (either LPCM or compressed MLP) with sampling frequencies from 44.1kHz (the standard for CD’s) up to 192kHz and sampling depth from 16 bits (the standard for CD’s) up to 24 bits. It has better frequency response and dynamic range than standard CD’s. In addition, many DVD-A titles are multi-channel.

How Can I Tell If a Disc Is DVD-A?
All DVD-A players and discs have the following logo on them:

DVDAudioLogo.jpg

What Is PCM?
The audio on a DVD-A is stored in either uncompressed linear Pulse Code Modulation (PCM) or the compressed Meridian Lossless Packing (MLP) algorithm.

PCM is a procedure to represent an analog signal in digital form. Its accuracy is dependent upon the Sampling Rate and Sample Size.

Sampling Rate or Sampling Frequency is defined as the number of times samples are taken per second to convert an analog signal to digital. A higher sampling rate (e.g., 192kHz or 192,000 samples per second) allows for higher frequencies to be represented. DVD-A is capable of frequencies from 0 to 96kHz.

Sample Size or Quantization is the number of bits used to represent the analog audio signal each time it is sampled in the analog-to-digital conversion process. A higher bit number allows a more accurate representation of the amplitude of the audio signal, resulting in better dynamic range. DVD-A is capable of recording a signal with a maximum dynamic range of 144db.

In uncompressed PCM format, it is possible to get up to 96kHz/16bit or 48kHz/24bit in 5.1, and 192kHz/24bit in stereo. To store 5.1 tracks in 88.2kHz/20bit, 88.2kHz/24bit, 96kHz/20bit or 96kHz/24bit on a DVD disc, the use of MLP compression is mandatory.

The Bit Rate or Data Rate is the number of bits-per-second that can be processed. The maximum uncompressed Bit Rate of DVD-A is: 96,000 (samples per second) x 16 (bits per sample) x 6 (channels) = 9.2Mbps, in uncompressed form.

What is Meridian Lossless Packing (MLP)?
Currently, the best listening experience to end-users comes with Linear PCM coding on a disc. Unfortunately, 6 channels or more of high-resolution music take up way too much bandwidth to fit even on a DVD. Using lossy perceptual compression codecs, such as MPEG, Dolby Digital, and DTS Digital, is one solution. Perceptual lossy compression techniques throw away the least significant bits of the audio input. Theoretically, they represent detail that is impossible to hear, or at least difficult to hear. Unfortunately, a lossy codec compresses content such that the result, when decompressed, is not exactly the same as the original master.

Unlike perceptual lossy data reduction, a lossless codec compresses the data without losing any of it when it is decompressed. The result, when decompressed, is exactly the same as the original master. Meridian Lossless Packing, developed by the British high-end audio manufacturer, is the data-reduction technique selected for DVD-Audio and typically provides about 50% data reduction.. It is licensed by Dolby Laboratories and enables up to six channels of 96 kHz/24 bit audio, or two channels of 192 kHz/24 bit audio onto a DVD-Audio disc. Dolby TrueHD, used in Blu-Ray and HD DVD, is based on MLP, and enables to encode 8 or more full-range channels at higher bit rates. For additional information on MLP, read DVD Benchmark - Part 6 - DVD-Audio.

What Is the Difference Between DVD-A and SACD?
DVD-A uses the DVD media and PCM encoding. To listen to DVD-A content, you need a DVD-A compatible DVD player. If you use a standard DVD player, you will only hear the stereo content or Dolby/DTS Digital content, depending on the encoding. You cannot play a DVD-A disc in your home or car CD/SACD player.

SACD uses optical discs and DSD encoding. To listen to SACD content, you need a SACD Player or a SACD-compatible DVD player. You can play the Hybrid SACD (not the standard SACD) in your CD (home or car) and standard DVD player. However, you will only hear the stereo CD content.

Comparison of DSD and PCM
Converting from analog sound to PCM and back to analog sound involves a number of processing steps. Each step causes distortions such as quantization noise (please refer to footnote 1). The noise may result in further deterioration of sound quality and needs to be filtered out. DSD, however, is a very simple way of converting analog signal to digital with a smaller probability of sound deterioration.

Because of the nature of converters used in PCM and DSD, one cannot make a direct comparison between the two formats. An approximation would place DSD in some aspects comparable to a PCM format that has a bit depth of 20 bits and a sampling frequency of 192kHz. PCM sampled at 24 bits provides theoretically an additional 24dB of dynamic range. Due to the effects of quantization noise, the usable bandwidth of the SACD format is approximately 100kHz, which is similar to 192kHz PCM.

What Type of Cables Do You Need for DVD-A?
DVD-A players are not permitted to digitally output encrypted PCM signals. Therefore, you cannot use Toslink (Optical) or Digital S/PDIF (Sony/Philips Digital Information Format) cables. Initially, players supported only multi-channel analog output (please refer to footnote 2). Later, some proprietary digital interfaces such as Denon Link or I-Link (IEEE 1394, Firewire) permitted encrypted transmission of PCM signals. HDMI (version 1.1 or above) can also be used for transmission of PCM signals. The HDMI version number does not refer to the cable. It refers to the transmission and receiver chips in the player and the receiver.

Can I copy a DVD-A?
DVD-A discs are copy protected and cannot legally be copied. Any attempt to break the code is a violation of copyright laws. However, the standard stereo or Dolby/DTS Digital content can be copied if it is not copy protected.

Can PS3 Play DVD-A Music?
PS3 does not support DVD-A. As a co-developer of the competing format (SACD), Sony has never supported DVD-A. PS3 can only play the lossy Dolby Digital or DTS Digital tracks.

Importance of Calibration
Many DVD-A and SACD titles are available in 5.1 multi-channel sound format. In order to enjoy the music in the most optimum way, you need to calibrate your audio system and adjust your speakers/subwoofer. Although many new receivers have their own built-in calibration programs, I highly recommend the use of an SPL meter in addition to them. Radio Shack offers two excellent choices below $50. I also encourage you to read Calibrating Your Audio with an SPL Meter. Pay close attention to the section at the end on subwoofer positioning and its interaction with the main speakers.

Where Can I Buy DVD-A Music?
There are many releases since the introduction of the format, mostly, but not exclusively, in Jazz and Classical music. You can check the following sites for DVD-A releases:

http://dvd-a.info/
http://www.amazon.com/s/ref=sr_pg_1?...dvd%20a&page=1
http://www.tower.com/tower_search/se...ion=0&div_id=2
http://store.acousticsounds.com/cate...?sct=dvd&id=23
http://www.cduniverse.com/browsecat....music&cat=1028
http://www.musicdirect.com/c-512-dvd-audio.aspx
http://www.jr.com/JRSectionView.proc...=610000#Format
http://search.ebay.com/search/search...=32%26fsoo%3D2

Popular DVD-A Players
http://www.oppodigital.com/
http://usa.denon.com/ProductDetails/...ndChangers.asp
http://us.marantz.com/Products/349.asp
http://www.pioneerelectronics.com/PU...liteDVDPlayers
http://www.onkyousa.com/prod_class.cfm?class=DVD
http://www.tacp.toshiba.com/dvd/prod...?model=sd-6980
http://www.arcam.co.uk/prod_diva_DV135_intro.cfm
http://www.arcam.co.uk/prod_diva_DV137_intro.cfm

DUALDISCS, DEMYSTIFIED

What is DualDisc?
DualDisc is a double-sided disc. It features an audio layer similar to standard CD on one side and a standard DVD layer on the other side. The format was developed by record companies (Warner Music, Universal Music Group, Sony/BMG, and EMI Music) in 2004 as an alternative to Hybrid SACD.

http://www.dualdisc.com/
http://en.wikipedia.org/wiki/DualDisc

How Are DualDiscs Made?
DualDiscs are made by attaching together a CD layer (0.9mm thick, 525MB, 60min) to a standard DVD layer (0.6mm thick, 4.7GB), resulting in a 1.5mm-thick double-sided disc.

What Does a DualDisc Contain?
On the CD side of a DualDisc, record companies provide PCM audio with standard 16bit and 44.1kHz sampling rate.

On the DVD side, most record companies provide the music on the CD side both in high-resolution (96kHz, 24bit) multi-channel DVD-Audio format and a lower-resolution Dolby/DTS Digital surround or stereo for compatibility with standard DVD players. They also provide DVD video content relevant to the music.

Because Sony is a co-developer of SACD format (competitor of DVD-A), Sony Music generally provides DVD video and only 48kHz, 16bit LPCM or Dolby Digital Surround music on the DVD side of their DualDiscs.

How Can I Tell If a Disc Is DualDisc?
All DualDiscs have the following logo on them:

DualDiscLogo.gif

Can You Use DualDiscs in a Standard CD Player?
Because the 0.9mm CD layer of DualDisc does not conform to Red Book CD specifications, which call for no less than 1.1mm, Sony and Philips have refused to allow DualDisc titles to carry the CD logo. In fact, some CD and DVD players may not be able to play the CD side of a DualDisc. As a result, some manufactures have issued warnings on their web sites:

Panasonic: http://www.panasonic.com/consumer_el.../DualDisc.html
Pioneer: http://www.cdrinfo.com/Sections/News...x?NewsId=13110
Playstation (PS2 and PS3): http://www.us.playstation.com/News/C.../DualDisc.html
Sony: http://www.css.ap.sony.com/usefulinf...b%20Notice.htm

What Is the Difference Between a DualDisc and a Hybrid SACD?
Hybrid SACDs are one-sided discs with two layers: a high resolution SACD layer and a lower resolution CD layer. They can be played in SACD players, standard CD or DVD players (only the stereo CD layer will play), and SACD-compatible DVD players.

DualDiscs are double-sided discs with a CD side and a DVD side. They can be played in DVD-A players and standard DVD players (only the lower resolution audio will play). They may or may not play in a home or car CD player.

Where Can I Buy DualDic Music?
http://www.amazon.com/s/ref=nb_ss_m/...words=DualDisc
http://www.cduniverse.com/search/xx/...a/DualDisc.htm
http://store.acousticsounds.com/cate...sct=dvd&id=157
http://music.search.ebay.com/dualdis...0QQsacatZ11233
http://www.tower.com/tower_search/se...lDisc&div_id=2

SACD, DVD-A, and DualDisc Reviews
http://www.audaud.com/index.php
http://www.highfidelityreview.com/index.asp

FOOTNOTES

1. When a DVD-A player is connected to a receiver with multi-channel analog cables, the player must perform digital to analog decoding and send the analog signal to the receiver. In this case, calibration and bass management adjustments such as speaker sizes and channel levels should be done in the player's setup menus or the receiver must have bass management for the 5.1 ANALOG inputs. If the player lacks calibration adjustments or the receiver cannot perform adjustments for analog inputs, bass management cannot be performed.
2. Quantization is the process of approximating a continuous range of values by a relatively-small set of discrete symbols or integer values (approximating analog signals with discrete digital values.) Quantization Noise is introduced by quantization in the analog-to-digital conversion process.