DVD-Audio
Encyclopedia
DVD-Audio 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.
to 5.1-channel surround sound
, at various sampling frequencies and sample rates. (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:
Audio on a DVD-Audio disc can be stored in many different bit depth/sampling rate/channel combinations:
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
. 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.
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 (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.
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. Cyberlink's PowerDVD Version 8 provides an official method of playing DVD-Audio discs. This feature was dropped from version 9 onwards. 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.
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.
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:
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", 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.
mechanism called Content Protection for Prerecorded Media (CPPM). 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. The 4C Entity also developed a similar specification, Content Protection for Recordable Media
(CPRM), which is used on Secure Digital card
s.
DVD-Audio's copy protection was overcome in 2005 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
.
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, Additionally, in 2007 the widely-used commercial software DVDFab Platinum
added DVD-Audio decryption, allowing users to back up a full DVD-A image to ISO.
Other high fidelity disc formats:
Audio format
An audio format is a medium for storing sound and music. The term is applied to both the physical recording media and the recording formats of the audio content – in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to...
for delivering high-fidelity audio content on a DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
. DVD-Audio is not intended to be a video delivery format and is not the same as video DVDs
DVD-Video
DVD-Video is a consumer video format used to store digital video on DVD discs, and is currently the dominant consumer video format in Asia, North America, Europe, and Australia. Discs using the DVD-Video specification require a DVD drive and a MPEG-2 decoder...
containing concert films or music videos.
The first discs entered the marketplace in 2000. DVD-Audio was in a format war
Format war
A format war describes competition between mutually incompatible proprietary formats that compete for the same market, typically for data storage devices and recording formats for electronic media. It is often characterized by political and financial influence on content publishers by the...
with Super Audio CD
Super Audio CD
Super Audio CD is a high-resolution, read-only optical disc for audio storage. Sony and Philips Electronics jointly developed the technology, and publicized it in 1999. It is designated as the Scarlet Book standard. Sony and Philips previously collaborated to define the Compact Disc standard...
(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 monoMonaural
Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path...
to 5.1-channel surround sound
Surround sound
Surround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and...
, at various sampling frequencies and sample rates. (The ".1" denotes a Low-frequency effects channel (LFE) for bass and/or special audio effects.)
Compared to the Compact Disc
Compact Disc
The Compact Disc is an optical disc used to store digital data. It was originally developed to store and playback sound recordings exclusively, but later expanded to encompass data storage , write-once audio and data storage , rewritable media , Video Compact Discs , Super Video Compact Discs ,...
, 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 rateSampling rateThe sampling rate, sample rate, or sampling frequency defines the number of samples per unit of time taken from a continuous signal to make a discrete signal. For time-domain signals, the unit for sampling rate is hertz , sometimes noted as Sa/s...
s 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 Audio bit depth In digital audio, bit depth describes the number of bits of information recorded for each sample. Bit depth directly corresponds to the resolution of each sample in a set of digital audio data... |
||||||
|---|---|---|---|---|---|---|
| 44.1 kHz | 48 kHz | 88.2 kHz | 96 kHz | 176.4 kHz | 192 kHz | |
| Mono Monaural Monaural or monophonic sound reproduction is single-channel. Typically there is only one microphone, one loudspeaker, or channels are fed from a common signal path... (1.0) |
||||||
| Stereo (2.0) | ||||||
| Stereo (2.1) | ||||||
| Stereo + mono surround (3.0 or 3.1) | ||||||
| Quad Quadraphonic Quadraphonic sound – the most widely used early term for what is now called 4.0 surround sound – uses four channels in which speakers are positioned at the four corners of the listening space, reproducing signals that are independent of one another... (4.0 or 4.1) |
||||||
| 3-stereo (3.0 or 3.1) | ||||||
| 3-stereo + mono surround (4.0 or 4.1) | ||||||
| Full surround Surround sound Surround sound encompasses a range of techniques such as for enriching the sound reproduction quality of an audio source with audio channels reproduced via additional, discrete speakers. Surround sound is characterized by a listener location or sweet spot where the audio effects work best, and... (5.0 or 5.1) |
||||||
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
LPCM
Linear pulse-code modulation is a method of encoding audio information digitally. The term also refers collectively to formats using this method of encoding...
format, which is either uncompressed or losslessly compressed with Meridian Lossless Packing
Meridian Lossless Packing
Meridian Lossless Packing, also known as Packed PCM , is a proprietary lossless compression technique for compressing PCM audio data developed by Meridian Audio, Ltd. MLP is the standard lossless compression method for DVD-Audio content and typically provides about 1.5:1 compression on most music...
. The maximum permissible total bit rate
Bit rate
In telecommunications and computing, bit rate is the number of bits that are conveyed or processed per unit of time....
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
Downmixing
Downmixing is a general term used for manipulating audio where a number of distinct audio channels are mixed together to produce a lower number of channels...
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 compatibilityBackward compatibility
In the context of telecommunications and computing, a device or technology is said to be backward or downward compatible if it can work with input generated by an older device...
with existing DVD-Video
DVD-Video
DVD-Video is a consumer video format used to store digital video on DVD discs, and is currently the dominant consumer video format in Asia, North America, Europe, and Australia. Discs using the DVD-Video specification require a DVD drive and a MPEG-2 decoder...
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
Dolby Digital
Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. It was originally called Dolby Stereo Digital until 1994. Except for Dolby TrueHD, the audio compression is lossy. The first use of Dolby Digital was to provide digital sound in cinemas from 35mm film prints...
5.1-channel audio track on the disc (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
Digital Theater System
DTS is a series of multichannel audio technologies owned by DTS, Inc. , an American company specializing in digital surround sound formats used for both commercial/theatrical and consumer grade applications...
96/24 5.1-channel, audio track.
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
Freeware
Freeware is computer software that is available for use at no cost or for an optional fee, but usually with one or more restricted usage rights. Freeware is in contrast to commercial software, which is typically sold for profit, but might be distributed for a business or commercial purpose in the...
audio player
Audio player (software)
An audio player is a kind of media player for playing back digital audio, including optical discs such as CDs, SACDs, DVD-Audio, HDCD, audio files and streaming audio....
foobar2000
Foobar2000
foobar2000 is a freeware audio player for Windows developed by Peter Pawlowski, a former freelance contractor for Nullsoft. It is known for its highly modular design and extensive SDK which allows third-party developers to do such things as completely replace the interface...
for Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
using an open source
Open source
The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
plug-in extension called DVDADecoder. Cyberlink's PowerDVD Version 8 provides an official method of playing DVD-Audio discs. This feature was dropped from version 9 onwards. 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.
Preamplifier/Surround Processor interface
In order to play DVD-Audio, a preamplifier or surround controller with six analog inputs was originally required. Whereas DVD-Video audio formats such as Dolby DigitalDolby Digital
Dolby Digital is the name for audio compression technologies developed by Dolby Laboratories. It was originally called Dolby Stereo Digital until 1994. Except for Dolby TrueHD, the audio compression is lossy. The first use of Dolby Digital was to provide digital sound in cinemas from 35mm film prints...
and DTS
Digital Theater System
DTS is a series of multichannel audio technologies owned by DTS, Inc. , an American company specializing in digital surround sound formats used for both commercial/theatrical and consumer grade applications...
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.
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
HDMI
HDMI is a compact audio/video interface for transmitting uncompressed digital data. It is a digital alternative to consumer analog standards, such as radio frequency coaxial cable, composite video, S-Video, SCART, component video, D-Terminal, or VGA...
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:
- The 6 audio channels can be decrypted and extracted in the player and sent to the amplifier along 6 standard analog cables.
- 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.
- The third option is via the S/PDIFS/PDIFS/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
(or TOSLINKTOSLINKTOSLINK is a standardized optical fiber connection system. Also known generically as an "optical audio cable," its most common use is in consumer audio equipment , where it carries a digital audio stream from components such as MiniDisc, CD and DVD players, DAT recorders, computers, and modern...
) 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.
- 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/PDIFS/PDIFS/PDIF is a digital audio interconnect used in consumer audio equipment over relatively short distances. The signal is transmitted over either a coaxial cable with RCA connectors or a fiber optic cable with TOSLINK connectors. S/PDIF interconnects components in home theaters and other digital high...
, 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 CDRed Book (audio CD standard)
Red Book is the standard for audio CDs . It is named after one of the Rainbow Books, a series of books that contain the technical specifications for all CD and CD-ROM formats.The first edition of the Red Book was released in 1980 by Philips and Sony; it was adopted by the Digital Audio Disc...
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
Record label
In the music industry, a record label is a brand and a trademark associated with the marketing of music recordings and music videos. Most commonly, a record label is the company that manages such brands and trademarks, coordinates the production, manufacture, distribution, marketing and promotion,...
, Universal Music, EMI
EMI
The EMI Group, also known as EMI Music or simply EMI, is a multinational music company headquartered in London, United Kingdom. It is the fourth-largest business group and family of record labels in the recording industry and one of the "big four" record companies. EMI Group also has a major...
and Warner Bros. Records
Warner Bros. Records
Warner Bros. Records Inc. is an American record label. It was the foundation label of the present-day Warner Music Group, and now operates as a wholly owned subsidiary of that corporation. It maintains a close relationship with its former parent, Warner Bros. Pictures, although the two companies...
, 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", 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
DualDisc
DualDisc was a type of double-sided optical disc product developed by a group of record companies including EMI Music, Universal Music Group, Sony/BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group and later under the aegis of the Recording Industry Association of America...
, 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
Grateful Dead
The Grateful Dead was an American rock band formed in 1965 in the San Francisco Bay Area. The band was known for its unique and eclectic style, which fused elements of rock, folk, bluegrass, blues, reggae, country, improvisational jazz, psychedelia, and space rock, and for live performances of long...
's American Beauty
American Beauty (album)
American Beauty is the fifth album by the Grateful Dead. It was recorded between August and September 1970 and originally released in November 1970 by Warner Bros. Records...
and R.E.M.
R.E.M.
R.E.M. was an American rock band formed in Athens, Georgia, in 1980 by singer Michael Stipe, guitarist Peter Buck, bassist Mike Mills and drummer Bill Berry. One of the first popular alternative rock bands, R.E.M. gained early attention due to Buck's ringing, arpeggiated guitar style and Stipe's...
's Automatic for the People
Automatic for the People
Automatic for the People is the eighth album by the American alternative rock band R.E.M., released in 1992 on Warner Bros. Records. While R.E.M...
, were re-released as a CD/DVD package or as a DualDisc.
Copy protection
DVD-Audio discs may optionally employ a copy protectionCopy protection
Copy protection, also known as content protection, copy obstruction, copy prevention and copy restriction, refer to techniques used for preventing the reproduction of software, films, music, and other media, usually for copyright reasons.- Terminology :Media corporations have always used the term...
mechanism called Content Protection for Prerecorded Media (CPPM). CPPM, managed by the 4C Entity
4C Entity
The 4C Entity is a consortium formed by IBM, Intel, Matsushita and Toshiba to establish a common platform for digital rights management schemes...
, 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
Digital watermarking
Digital watermarking is the process of embedding information into a digital signal which may be used to verify its authenticity or the identity of its owners, in the same manner as paper bearing a watermark for visible identification. In digital watermarking, the signal may be audio, pictures, or...
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. The 4C Entity also developed a similar specification, Content Protection for Recordable Media
Content Protection for Recordable Media
Content Protection for Recordable Media and Pre-Recorded Media is a mechanism for controlling the copying, moving and deletion of digital media on a host device, such as a personal computer, or other digital player...
(CPRM), which is used on Secure Digital card
Secure Digital card
Secure Digital is a non-volatile memory card format developed by the SD Card Association for use in portable devices. The SD technology is used by more than 400 brands across dozens of product categories and more than 8,000 models, and is considered the de-facto industry standard.Secure Digital...
s.
DVD-Audio's copy protection was overcome in 2005 by tools which allow data to be decrypted or converted to 6 channel .WAV files without going through lossy digital-to-analog
Digital-to-analog converter
In electronics, a digital-to-analog converter is a device that converts a digital code to an analog signal . An analog-to-digital converter performs the reverse operation...
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
DVD-Audio Explorer
DVD-Audio Explorer is a software application for extracting audio tracks off a DVD-Audio disc and save them to a computer. The program also supports saving tracks to stereo and multichannel wav format...
was released, containing aforementioned libdvdcpxm coupled with an open source MLP decoder
Decoder
A decoder is a device which does the reverse operation of an encoder, undoing the encoding so that the original information can be retrieved. The same method used to encode is usually just reversed in order to decode...
.
Like DVD-Video decryption, such tools may be illegal to use in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
under the controversial Digital Millennium Copyright Act
Digital Millennium Copyright Act
The Digital Millennium Copyright Act is a United States copyright law that implements two 1996 treaties of the World Intellectual Property Organization . It criminalizes production and dissemination of technology, devices, or services intended to circumvent measures that control access to...
. While the Recording Industry Association of America
Recording Industry Association of America
The Recording Industry Association of America is a trade organization that represents the recording industry distributors in the United States...
has been successful in keeping these tools off websites, they are still distributed on P2P file sharing networks and newsgroups, Additionally, in 2007 the widely-used commercial software DVDFab Platinum
DVDFab
DVDFab is a Microsoft Windows program that allows the decryption and copying of video DVDs, Blu-ray discs, and some HD DVDs. Its distribution is based in Beijing.-Features:...
added DVD-Audio decryption, allowing users to back up a full DVD-A image to ISO.
DVD-Audio authoring software
Normal DVD-Video authoring software usually does not support DVD-Audio creation, so there is some special software:Macintosh
- Sonic SolutionsSonic SolutionsSonic Solutions, acquired by Rovi Corporation in 2010, was a computer software company headquartered in Novato, California. In addition to having a number of offices in the U.S., the company also maintained offices in Europe and Asia.-History:...
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
- 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. 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 freeFree softwareFree software, software libre or libre software is software that can be used, studied, and modified without restriction, and which can be copied and redistributed in modified or unmodified form either without restriction, or with restrictions that only ensure that further recipients can also do...
/open sourceOpen sourceThe term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...
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 PackingMeridian Lossless PackingMeridian Lossless Packing, also known as Packed PCM , is a proprietary lossless compression technique for compressing PCM audio data developed by Meridian Audio, Ltd. MLP is the standard lossless compression method for DVD-Audio content and typically provides about 1.5:1 compression on most music...
- DualDiscDualDiscDualDisc was a type of double-sided optical disc product developed by a group of record companies including EMI Music, Universal Music Group, Sony/BMG Music Entertainment, Warner Music Group, and 5.1 Entertainment Group and later under the aegis of the Recording Industry Association of America...
- DVDDVDA DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....
Other high fidelity disc formats:
- Super Audio CDSuper Audio CDSuper Audio CD is a high-resolution, read-only optical disc for audio storage. Sony and Philips Electronics jointly developed the technology, and publicized it in 1999. It is designated as the Scarlet Book standard. Sony and Philips previously collaborated to define the Compact Disc standard...
- Earlier attempts at high fidelity that stayed within the CDDA standard: XRCD and HDCD.
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.