DVD-Audio

DVD-Audio

Media type	Optical disc
Encoding	Meridian Lossless Packing or uncompressed LPCM[1]
Capacity	up to 8.5 GB
Read mechanism	640 nm wavelength semiconductor laser
Standard	DVD Books, Part 4, DVD-Audio Book, DVD Audio Recording Book [2][3][4]
Developed by	DVD Forum
Usage	Audio storage
Extended from	DVD

DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs containing concert films or music videos.

The first discs entered the marketplace in 2000. DVD-Audio was in a format war with Super Audio CD (SACD), another format for delivering high-fidelity audio content. Neither format has gained a strong position in any consumer market.

Audio specifications

DVD-Audio offers many possible configurations of audio channels, ranging from single-channel mono to 5.1-channel surround sound, at various sampling frequencies and sample rates.^[5] (The ".1" denotes a Low-frequency effects channel (LFE) for bass and/or special audio effects.)

Compared to the Compact Disc, the much higher capacity DVD format enables the inclusion of either:

• Considerably more music (with respect to total running time and quantity of songs) or
• Far higher audio quality, reflected by higher linear sampling rates and higher bit-per-sample resolution, and/or
• Additional channels for spatial sound reproduction.

Audio on a DVD-Audio disc can be stored in many different bit depth/sampling rate/channel combinations:

	16-, 20- or 24-bit depth
	44.1 kHz	48 kHz	88.2 kHz	96 kHz	176.4 kHz	192 kHz
Mono (1.0)	Yes	Yes	Yes	Yes	Yes	Yes
Stereo (2.0)	Yes	Yes	Yes	Yes	Yes	Yes
Stereo (2.1)	Yes	Yes	Yes	Yes	No	No
Stereo + mono surround (3.0 or 3.1)	Yes	Yes	Yes	Yes	No	No
Quad (4.0 or 4.1)	Yes	Yes	Yes	Yes	No	No
3-stereo (3.0 or 3.1)	Yes	Yes	Yes	Yes	No	No
3-stereo + mono surround (4.0 or 4.1)	Yes	Yes	Yes	Yes	No	No
Full surround (5.0 or 5.1)	Yes	Yes	Yes	Yes	No	No

Optical discs

Optical disc Optical disc drive Optical disc authoring Authoring software Recording technologies Recording modes Packet writing
Optical media types
Blu-ray Disc (BD): BD-R, BD-RE DVD: DVD-R, DVD+R, DVD-R DL, DVD+R DL, DVD-R DS, DVD+R DS, DVD-RW, DVD+RW, DVD-RAM, DVD-D, DVD-A, HVD, EcoDisc Compact Disc (CD): Red Book, CD-ROM, CD-R, CD-RW, 5.1 Music Disc, SACD, Photo CD, CD Video (CDV), Video CD (VCD), SVCD, CD+G, CD-Text, CD-ROM XA, CD-i Universal Media Disc (UMD) Enhanced Versatile Disc (EVD) Forward Versatile Disc (FVD) Holographic Versatile Disc (HVD) China Blue High-definition Disc (CBHD) HD DVD: HD DVD-R, HD DVD-RW, HD DVD-RAM High definition Versatile Multilayer Disc (HD VMD) VCDHD GD-ROM MiniDisc (MD) (Hi-MD) Laserdisc (LD) (LD-ROM) Video Single Disc (VSD) Ultra Density Optical (UDO) Stacked Volumetric Optical Disk (SVOD) Five dimensional disc (5D DVD) Nintendo optical disc (NOD)
Standards
SFF ATAPI/MMC Mount Rainier (packet writing) Mount Fuji (layer jump recording) Rainbow Books File systems ISO 9660 Joliet Rock Ridge / SUSP El Torito Apple ISO 9660 Extensions Universal Disk Format (UDF) ISO 13490
See also
History of optical storage media High definition optical disc format war
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Different bit depth/sampling rate/channel combinations can be used on a single disc. For instance, a DVD-Audio disc may contain a 96 kHz/24-bit 5.1-channel audio track as well as a 192 kHz/24-bit stereo audio track. Also, the channels of a track can be split into two groups stored at different resolutions. For example, the front speakers could be 96/24, while the surrounds are 48/20.

Audio is stored on the disc in Linear PCM format, which is either uncompressed or losslessly compressed with Meridian Lossless Packing.^[1] The maximum permissible total bit rate is 9.6 Megabits per second. Channel/resolution combinations that would exceed this need to be compressed. In uncompressed modes, it is possible to get up to 96/16 or 48/24 in 5.1, and 192/24 in stereo. To store 5.1 tracks in 88.2/20, 88.2/24, 96/20 or 96/24 MLP encoding is mandatory.

The LFE channel is actually full range, and can be recorded at the same resolution as the other channels. This permits it to be used instead as an extra main channel, for example as a "height" speaker above the listening position; this has been done on some releases. Such usage is non-standard, and will often require special set-up by the end-user.

If no native stereo audio exists on the disc, the DVD-Audio player may be able to downmix the 5.1-channel audio to two-channel stereo audio if the listener does not have a surround sound setup (provided that the coefficients were set in the stream at authoring). Downmixing can only be done to two-channel stereo, not to other configurations, such as 4.0 quad. DVD-Audio may also feature menus, text subtitles, still images and video, plus in high end authoring systems it is also possible to link directly into a Video_TS folder that might contain video tracks, as well as PCM stereo and other "bonus" features.

Player compatibility

With the introduction of the DVD-Audio format, some kind of backward compatibility with existing DVD-Video players was desired, although not required. To address this, most DVD-Audio discs also contain DVD-Video compatible data that allows the standard DVD-Video Dolby Digital 5.1-channel audio track on the disc^[6] (which can be downmixed to two channels for listeners with no surround sound setup). Some discs also include a native Dolby Digital 2.0 stereo, and even a DTS 96/24 5.1-channel, audio track.^[7]

Since the DVD-Audio format is a member of the DVD family, a single disc can have multiple layers, and even two sides that contain audio and video material. A common configuration is a single-sided DVD with content in both the DVD-Video (VIDEO_TS) and DVD-Audio (AUDIO_TS) directories. The high-resolution, Packed PCM audio encoded using MLP is only playable by DVD players containing DVD-Audio decoding capability. DVD-Video content, which can include LPCM, Dolby or DTS material, and even video, makes the disc compatible with all DVD players. Other disc configurations may consist of double layer DVDs (DVD-9) or two-sided discs (DVD-10, DVD-14 or DVD-18). Some labels have released two-sided DVD titles that contain DVD-Audio content on one side and DVD-Video content on the other, the Classic Records HDAD being one such example.

Unofficial playback of DVD-Audio on a PC is now possible through freeware audio player foobar2000 for Windows using an open source plug-in extension called DVDADecoder.^[8] Cyberlink's PowerDVD Version 8 provides an official method of playing DVD-Audio discs. This feature was dropped from version 9 onwards.^[9] Creative also provide a dedicated DVD-Audio player with some of its Soundblaster products, but this latter option is not compatible with versions of Windows later than XP.^[10]

Preamplifier/Surround Processor interface

In order to play DVD-Audio, a preamplifier or surround controller with six analog inputs was originally required.^[11] Whereas DVD-Video audio formats such as Dolby Digital and DTS can be sent via the player's digital output to a receiver for conversion to analog form and distribution to speakers, DVD-Audio is not allowed to be delivered via unencrypted digital audio link at sample rates higher than 48 kHz (i.e., ordinary DVD-Video quality) due to concerns about digital copying.^[11]

However encrypted digital formats have now been approved by the DVD Forum, the first of which was Meridian Audio's MHR (Meridian High Resolution). The High Definition Multimedia Interface (HDMI 1.1) also allows encrypted digital audio to be carried up to DVD-Audio specification (6 × 24-bit/96 kHz channels or 2 × 24-bit/192 kHz channels). The six channels of audio information can thus be sent to the amplifier by several different methods:

1. The 6 audio channels can be decrypted and extracted in the player and sent to the amplifier along 6 standard analog cables.
2. The 6 audio channels can be decrypted and then re-encrypted into an HDMI or IEEE-1394 (Firewire) signal and sent to the amplifier, which will then decrypt the digital signal and then extract the 6 channels of audio. HDMI and IEEE-1394 encryption are different from the DVD-A encryption and were designed as a general standard for a high quality digital interface. The amplifier has to be equipped with a valid decryption key or it won't play the disk.
3. The third option is via the S/PDIF (or TOSLINK) digital interface. However, because of concerns over unauthorized copying, DVD-A players are required to handle this digital interface in one of the following ways:
   • Turn such an interface off completely. This option is preferred by the music publishers.
   • Downconvert the audio to a 2-channel 16-bit/48 kHz PCM signal. The music publishers are not enthusiastic about this because it permits the production of a CD-quality copy, something they still expect to sell, besides DVD-A.
   • Downconvert the audio to 2 channels, but keeping the original sample size and bit rate if the producer sets a flag on the DVD-A disc telling the player to do so.
4. A final option is to modify the player, capturing the high resolution digital signals before they are fed to internal D/A converters and convert it to S/PDIF, giving full range digital (but only stereo) sound. There exist already do-it-yourself solutions for some players. There also exists an option to equip a DVD-A player with multiple S/PDIF outputs, for full resolution multichannel digital output. See: Six channel S/P-DIF output board.

Sound quality

From a purely technical standpoint, the audio resolution of a DVD-Audio disc can be substantially higher than standard red book CD audio. DVD-Audio supports bit depths up to 24-bit and sample rates up to 192 kHz, while CD audio is 16-bit, 44.1 kHz. In both cases, the source recording may have been made at a much higher bit and sample rate, and down-converted for commercial release.

Many DVD-Audio releases are older, standard-definition audio recordings that have been remixed in 5.1 and upsampled to DVD-Audio's higher resolution. However, the fidelity of the upsampled audio will be limited by the source material quality, when the master recording is in digital format, and may not exceed the quality of existing CD releases of the same albums. Recordings that are made using high-resolution PCM encoding can be released with a resolution that is higher than standard CD.

Three of the major music labels, Universal Music, EMI and Warner Bros. Records, and several smaller audiophile labels (such as AIX Records, Claudio Records and DTS Entertainment) have released or are continuing to release albums on DVD-Audio, but the number is minimal compared to standard CDs. New high-definition titles have been released in standard DVD-Video format (which can contain two-channel Linear PCM audio data ranging from 48 kHz/16-bit to 96 kHz/24-bit), "HDAD",^[12] which includes a DVD-Video format recording on one side and DVD-Audio on the other, CD/DVD packages, which can include the album on both CD and DVD-Audio, or DualDisc, which can contain DVD-Audio content on the DVD side. In addition, some titles that were initially released as a standalone DVD-Audio disc, such as The Grateful Dead's American Beauty and R.E.M.'s Automatic for the People, were re-released as a CD/DVD package or as a DualDisc.

Copy protection

DVD-Audio discs may optionally employ a copy protection mechanism called Content Protection for Prerecorded Media (CPPM).^[13] CPPM, managed by the 4C Entity, was designed to prevent users from extracting audio to computers and portable media players.

Because DVD-Video's content-scrambling system (CSS) was quickly broken, DVD-Audio's developers sought a better method of blocking unauthorized duplications. They developed CPPM, which uses a media key block (MKB) to authenticate DVD-Audio players. In order to decrypt the audio, players must obtain a media key from the MKB, which also is encrypted. The player must use its own unique key to decrypt the MKB. If a DVD-Audio player's decryption key is compromised, that key can be rendered useless for decrypting future DVD-Audio discs. DVD-Audio discs can also utilize digital watermarking technology developed by the Verance Corporation, typically embedded into the audio once every thirty seconds. If a DVD-Audio player encounters a watermark on a disc without a valid MKB, it will halt playback.^[14] The 4C Entity also developed a similar specification, Content Protection for Recordable Media (CPRM), which is used on Secure Digital cards.

DVD-Audio's copy protection was overcome in 2005^[14] by tools which allow data to be decrypted or converted to 6 channel .WAV files without going through lossy digital-to-analog conversion. Previously that conversion had required expensive equipment to retain all six channels of audio rather than having it downmixed to stereo. In the digital method, the decryption is done by a commercial software player which has been patched to allow access to the unprotected audio.

In 2007 the encryption scheme was overcome with a tool called dvdcpxm. In 12 February 2008 a program called DVD-Audio Explorer was released, containing aforementioned libdvdcpxm coupled with an open source MLP decoder.^[15]

Like DVD-Video decryption, such tools may be illegal to use in the United States under the controversial Digital Millennium Copyright Act. While the Recording Industry Association of America has been successful in keeping these tools off websites, they are still distributed on P2P file sharing networks and newsgroups,^[16] Additionally, in 2007 the widely-used commercial software DVDFab Platinum added DVD-Audio decryption, allowing users to backup a full DVD-A image to ISO.^[17]

DVD-Audio authoring software

Normal DVD-Video authoring software usually does not support DVD-Audio creation, so there is some special software:

Macintosh

• Sonic Solutions DVD Creator AV – The first DVD-Audio authoring solution available. A spin off of the popular high end DVD Video authoring package. It allows DVD-Audio authoring at the command line level only. Still widely used but no longer sold or supported by Sonic Solutions.
• Sonic Studio SonicStudio HD – Macintosh based tool used for High Density audio mastering and to prepare audio for DVD-A authoring in One Click DVD.
• Sonic Studio^[18]
• Sonic OneClick DVD – Converts prepared Sonic Studio EDLs into binary MLP files to be used in the authoring tool. Also generates scriptFile information to be added to DVD Creator AV projects.
• DVD audio Tools: console application dvda-author (version 08.07), see below.
• Apple Logic Pro 8 - When bouncing, choose "CDDA" under destination, and then choose DVD-A from the popup menu.
• Minnetonka discWelder Bronze is now available for Macintosh.^[19] Very simple to use if you just want to burn your own files to listen to in this format.
• Burn General purpose CD and DVD burning utility that can write AUDIO_TS data. Select "Audio" tab then "DVD-Audio" from the drop-down menu.

Windows

• Minnetonka discWelder
• Cirlinca DVD-AUDIO Solo
• Steinberg WaveLab Steinberg
• Gear Pro Mastering Edition Gear Pro Mastering Edition
• DVD audio tools package (see below).
• Samplitude

Linux

• A project called DVD audio Tools provides free/open source DVD-Audio authoring tools for Linux and other *nix platforms (FreeBSD, OpenSolaris,...).
  Windows (console application) binaries are also available. DVD-Audio/Video discs (aka Hybrid or Universal DVDs) are also supported.

See also

• Meridian Lossless Packing
• DualDisc
• DVD

Other high fidelity disc formats:

• Super Audio CD
• Earlier attempts at high fidelity that stayed within the CDDA standard: XRCD and HDCD.

References

1. ^ ^{a b} Jim Taylor. "DVD Frequently Asked Questions (and Answers) - Details of DVD-Audio and SACD". http://dvddemystified.com/dvdfaq.html#3.6.1. Retrieved 2010-03-20. 
2. ^ DVD FLLC (2009-02) DVD Book Construction - list of all available DVD Books, Retrieved on 2009-07-24
3. ^ DVD FLLC DVD Format Book - History of Supplements for DVD Books, Retrieved on 2009-07-24
4. ^ MPEG.org, DVD Books overview, Retrieved on 2009-07-24
5. ^ "Understanding DVD-Audio" (PDF). Sonic Solutions. http://patches.sonic.com/pdf/white-papers/wp_dvd_audio.pdf. Retrieved 2007-07-12. 
6. ^ "SACD & DVD-Audio: Ultra-High-Resolution Music". Crutchfield Advisor. http://www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/home/cd_dvdsacd.html. Retrieved 12 July 2007. 
7. ^ "What is DVD-Audio?". 5dot1.com. http://www.5dot1.com/articles/dvd_audio.html. Retrieved 12 July 2007. 
8. ^ Maxim V. Anisiutkin. "DVD-Audio Decoder and Watermark Detector". SourceForge. http://dvdadecoder.sourceforge.net/. Retrieved 19 October 2010. 
9. ^ http://www.cyberlink.com^{[not specific enough to verify]}
10. ^ http://uk.creative.com^{[not specific enough to verify]}
11. ^ ^{a b} "DVD-Audio Tutorial". TimeForDVD.com. 2002-06-05. http://www.timefordvd.com/tutorial/DVD-AudioTutorial.shtml. Retrieved 2007-07-12. 
12. ^ "HDAD" at surroundablog.blogs.com
13. ^ Labriola, Don (2003-08-25). "Digital Content Protection, Part II". ExtremeTech. http://www.extremetech.com/article2/0,1558,1231582,00.asp. Retrieved 2007-07-12. 
14. ^ ^{a b} Robinson, Stuart M (2005-06-07). "DVD-Audio Copy Protection Defeated via WinDVD Software Hack". HighFidelityReview.com. Archived from the original on 2007-06-08. http://web.archive.org/web/20070608032029/http://www.highfidelityreview.com/news/news.asp?newsnumber=14550899. Retrieved 2007-07-12. 
15. ^ "DVD-Audio ripper". http://forum.doom9.org/showthread.php?p=1099342#post1099342. Retrieved 2008-04-09. 
16. ^ "DVD-Audio's CPPM Circumvented". Slashdot.org. 2005-07-06. http://it.slashdot.org/article.pl?sid=05/07/06/1740206. Retrieved 2007-07-12. 
17. ^ "DVDFab updated to support DVD-Audio/CPPM". http://forum.doom9.org/showthread.php?t=127870. Retrieved 2008-04-15. 
18. ^ http://www.sonicstudio.com
19. ^ http://www.minnetonkaaudio.com/products/discwelder01.html

External links

• The 4C Entity LLC – Licensors of the Content Protection for Prerecorded Media (CPPM) specification.
• "DVD-Audio versus SACD: Perceptual Discrimination of Digital Audio Coding Formats" (PDF) Audio Engineering Society Convention Paper 6086.