DVD-Audio specifications have been established to be a global standard for the next generation of au-dio media, satisfying demands from the recording industry, hardware manufacturers, and other groupsworldwide. DVD-Audio provides a music carrier not only for high-quality and multichannel music, butalso for a variety of value-added contents to supplement a user's audio experience. An outline and the ma-jor functions or features offered by DVD-Audio specifications are presented.

Editor's Note: Bike H. Suzuki is the

i!v::o1chair of DVD Forum/WG-4. Norihiko I Part 4. ]Fuchigami and Tosio Kurojwa are mem-bers of DVD Forum/WG-4. The content Application LAudio Spec. J

of this article is based on four technical Specifications 3. .....................................ipaperspresentedattheAES9thRegion- Soec....................!al Convention, Tokyo, Japan, 1999 June , , ['--t ..............23-25: Fuchigami and Kuroiwa; Ya- FileSystemmamoto and Sawabe; Otomo; and Mori, Specifications Part 2. File System Specifications

H HKozuka,ShinboandAbe. PhysicalINTRODUCTION Specifications Part 1. Physical Specifications

SincetheaudioCDappearedin1982it _i i i i

has been widely accepted as a way to DVD Discs ROM ][ VIDEO j [AUDIOdeliverhigh-qualitydigitalmusic.Mu- .sic production methods and transmis- * : Recordof VideoContentsis possiblesion media have been developed basedon digital signal-processing technolo- Fig. 1. DVD specifications for DVD-ROM, DVD-Video, and DVD-Audio read-onlygies. Especially for storage media, opti- disks, parts 1 to 4.cal disks, represented by digital versa-tile disks (DVD), now have six or more the DVD family specifications, dio application specifications. DVD-times the data capacity of conventional This article describes the position of Audio, as well as DVD-Video (seeCDs. Listeners are anticipating that DVD-Audio within the DVD-ROM "DVD Specifications for Read-Onlylarge-capacity DVDs will have disk family, basic concepts, general Disc Part 3: Video Specifications Ver-supreme audio quality and better specifications of the DVD-Audio disk, sion 1.1") and DVD-ROM itself, usesound-field reproduction, the relation between disks and players, parts 1 and 2, which form the founda-

The DVD Forum promotes these and the major specifications of DVD- tion of the DVD-ROM systems.improvements via the establishment of Audio contents. On a DVD-Audio disk, while the au-DVD-ROM specifications (see Suzu- dio and related contents are recorded inki, 1999, and "DVD Specifications for DVD-AUDIOWITHINDVD-ROMDISK the AUDIO_TS directory in compli-Read-Only Disk Part 4: Audio Specifi- FA_/IJLY ance with part 4, the video contentscations Version 1.0"). DVD-Audio is DVD-Audio specifications have been (video tracks, described later) can beaimed primarily at meeting the re- added to "DVD Specifications for recorded inthe VIDEO_TS directory inquirements for the new-generation au- Read-Only Disc" as a new generation compliance with the data structure ofdio media proposed by the Internation- of audio disk specifications. As shown part 3, video specifications. Thereforeal Steering Committee (ISC), in Fig. 1, the specifications for DVD- DVD-Video-compliant players canrepresenting the three recording indus- Audio disks are provided in compliance play back the video contents on DVD-try associations IFPI, RIAA, and with parts 1, 2, and 4 of"DVD Specifi- Audio disks.RIAJ. DVD-Audio provides features cations for Read-Only Disc," physicalrelated to the high-quality audio con- specifications, file system specifica- BASaCCONCEPTSOF DVD-AUDIOtent and also offers various value- tions, and audio specifications. Part 4 In developing the DVD-Audio specifi-added content capabilities common to was recently published to define the au- cations, DVD Forum Audio Working

1228 d. Audio Eng. Soc,, Vol. 48, No. 12, 2000 December

Group 4, chaired by JVC, tried to imple-ment the 15 requirements proposed bythe ISC. Almost all of the requirementshave been incorporated successfully intothe DVD-Audio specifications.

While producing the DVD-Audiospecifications, Working Group 4 alwaystried to follow these basic concepts:

• High-Quality Audio A capacity aslarge as 4.7 GB (G = 109) for DVDdisks and a transfer rate as high as 9.6Mbit/s are fully utilized to implementrecord and playback of the highestquality stereo data and high-qualitymultichannel data. Another primaryrequirement is that any high-qualitycontent have a playing time longer Fig. 2. Hierarchical structure of DVD-Au.dio'smain contents, showing example withthan 74 minutes, multiple groups and optional indexes.• Incorporation of Multimedia Fea-

tures Value-added contents such as still standpoint of the user's access. DVD- As explained, the user's access to thepictures, text information, moving pic- Audio disks are configured hierarchical- structure of DVD-Audio contents istures, and menu functions are recorded ly with a maximum of nine groups per rather simple. The consideration herefor an enriched and enhanced high- album, a maximum of 99 tracks per was that navigation in DVD-Audioquality audio experience, group, and a maximum of 99 indexes should be easy, even without the aid of

• Proper Navigation Configuration per track (optional). Each piece of music the visual navigation of DVD-Video.for Audio Media Based on the naviga- (each song) is referred to as a track, as it Fig. 3 shows the variety of contentstion configuration of DVD-Video, is on conventional audio CDs. available on a DVD-Audio disk.DVD-Audio implements a simple Each group is a collection of tracks Tracks include audio tracks (mandate-structure of navigation suited to audio to be presented continuously, which ry) for recording the high-quality audioapplications, may correspondto an audio CD disk. A contents, complying with part 4 of the• Effective Reuse of DVD-Video Re- group would be utilized to carry acom- specifications and video tracks (option-

sources The data structure of DVD- plete music title with multiple songs, or al) for recording video contents corn-Video is studied to make use of the re- to deliver another title by reusing the plying with part 3 of the specifications.sources of DVD-Video authoring songs in other groups in a different A description of each content is dis-systems and those of DVD-Videoplay- playback order, cussed next.ers. Special consideration is given to Listeners can locate any group orthe video contents (video tracks) of track directly with a remote control Audio Tracks, Still Pictures, andDVD-Audio so they comply with the unit. The player starts playing back Real-Time Textsubset (section 3.2.2) of DVD-Video from the specified position in a group, Audio tracks must use the linear PCM orspecifications and are fully compatible and after finishing the presentation of lossless coding scheme known aswith the video titles of DVD-Video. the group, the player stops or automati- packed PCM (see Gerzon et al, 1999).• Provisions for Copyright Manage- cally presents a visual menu provided Packed PCM is very effective in extend-

ment An advanced system of copyright by the content provider, ing playback to allow for highermanagement is strongly de-manded by the music indus-try for a new high-quality,next-generation audio disk.DVD-Audio specificationsprovide reserved fields todefine control flags for anycopy-protection manage-ment scheme.

GENERALSPECIF|CATBONSOF DVD-AUDaODQSKS "-,

Fig. 2 shows the hierarchical Fig. 3. Contents available on DVD-Audiodisk. Audio tracks andvideo tracks are mainstructureof themain contents contents, shown in Fig. 2 as tracks. All contents on disk are optional except for audio data ofof DVD-Audio from the audio tracks.

J. Audio Eng. Soc., VoL 48, No. 12, 2000 December 1229

DVD-Audio Specifications

Visual Menu

Table 1. Data elements on DVD-Audio disk. The visual menu gives visual access tothe contents on a track or group of a

Element Outline of contents DVD-Audio disk through a menu pic-SAMG • Navigationinformationfor simple audioplayer, ture on the screen.Information such as

which has only two-channel audio output liner notes and discography can also beAMG • Information to navigate entire disk, may include contained as value-added contents. The

optionaltextmanager visual menu of DVD-Audio providescapabilities quite like those of the title

• AMG menu video object set for visual menu menu of DVD-Video.ASVS • Information to navigate still pictures The future extensibility of the DVD-

•Audio stillvideo object set for still pictures Audio specifications has been takeninto consideration by reserving some

ATS • Informationto navigateATS flag areas for defining optional audio• Audio object set for audio data and optional RTI of coding schemes for audio tracks andaudio tracks for defining any application other than

VMG • Informationto navigatevideopart real-timetext in RTIin thefuture.

V-fS • Informationto navigateVTS Internal Structureof OVO-Audio

• Video object set for video/audiodataof videotracks In the foregoing sections the hierarchi-cal structure and the contents of DVD-Audio have been described from the

quality multichannel recordings, directory in compliance with part 3, user's point of view. In contrast, Fig. 4Audio tracks can accommodate super- video specifications, with some restfic- shows the actual internal data structure

wide-range stereo music sampled at 192 tions applied. The restrictions forbid of a DVD-Audio disk. The figure illus-kHz, high-quality multichannel music the use of functions such as multistory, trates the case in which video tracks aresampled at 96 kHz, and audio data hav- region control, and parental control, recorded and shows only the directoriesing the quality equivalent to convention- which are not necessary for an audio related to DVD applications, AU-al audio CDs. Hence the audio parame- application. DIO_TS and VIDEO_TS.ters can be flexibly selected according to Only the audio data contained in In the AUDIO_TS directory, simplethe intent of the content provider, video tracks can be played back, if per- audio manager (SAMG), audio manag-

Audio tracks can be accompanied by mitted by the content provider, on an er (AMG), audio still video set (ASVS,multiple still pictures in a slide-show audio-only player, as described in optional), and one or more audio titlemode or in a browsable mode. Brows- "DVD-Audio Players and Disks." On sets (ATSs) are recorded in that order,able pictures are a function unique to DVD-Video players, video tracks are in compliance with part 4 of the speci-DVD-Audio, which is not supported played back as titles or chapters, fications. In the VIDEO_TS directory,eveninDVD-Video. videomanager(VMG)andoneormore

The data for still pictures are record- Text Manager video title sets (VTSs) are recorded ined in the audio-still-video set (ASVS) The text manager totally controls the that order, in compliance with both partseparately from the audio data in the static text information that is not for 3 and the restrictions listed in part 4.audio-title set (ATS) so as not to dis- real-time use on a language-by-lan- Table 1 gives an outline of each dataturb the recording of high-quality audio guage basis. This information includes element shown in Fig. 4. In the tabledata (see Table i). the names of an album, groups, and the term "set" specifies a collection of

Real-time information (RTI) can be tracks, the names of artists, and the In- particular data units. For instance, au-multiplexed to an audio track, and the ternet addresses related to the contents, dio object set means a collection of _.bRTI presentation can be synchronizedto the audio presentation. DVD-Audioversion 1.0 defines real-time text as an

,_ AUDIO_TSdirectory _-application of the RTI. Real-time text is

svsI .........: .....suitablefor displayingsuchinforma- ISAMG] i....>tion as lyrics or liner notes along withthe audio presentation. Real-time text .............................................::::::::::::::::::::::::"'="supports a maximum of eight lan- _ V1DEOTSdirectory

guages to be presented selectively. (:'_'::}""V'MGIVTS#1 ............I'I""!VTS;k'!Video Tracks

Video tracks are used mainly for pre-senting music video clips. They are Fig. 4. Internal data structure of DVD-Audio disk, showing VIDEO_TS directory torecorded optionally in the VIDEO_TS carry video tracks.

1230 J Audno Eng. Soc, Vol. 48, No. 12, 2000 December

DVD-Audio Specifications

which presents one or more audio ob-Table 2. Relationship between DVD disks and players, jects, as shown in Fig. 5. When video

tracks are optionally recorded, they areUniversal Video made as an ATT translated into a VTS

Disk Contents AOP VCAP Player PlayeR title in a VTS.DVD- Title menu NP NP M M There are three types of group con-Video figurations:

Videotitle NP NP M M * Group composed only of ATTs forDVD- Visual menu NP M M NP audiotracksAudio • Group composed only of ATTs for

video tracksAudio Audio M M M NP ° Group composed of ATTs for au-track

did tracks and an ATT for video tracksStillpictures NP M M NP

(in this case, certain rules apply to theReal-timetext O O O NP configurationofthetitles).

Video Video NP M M M Usingsuchflexibleconfigurationsoftrack groupsandtides,thecontentprovider

Audio M* M M M can always provide contents on aDVD-Audio disk.

Textmanager O NPDVD-AudioPlayers and Disks

Notes: M-mandatory, O=optional, NP=not playableOnly portions allowed are playable. DVD-Audio not only offers pure, high-

quality audio, but also supports variousvalue-added contents including video.

one or more audio objects, as an audio object (ADD) in an ATS, With increasing demand for mobile orEach element is composed of one whereas the data for video tracks are portable audio taken into consideration,

or more files and is located in the di- recorded as a video object (VOB) in a DVD-Audio specifications define tworectory. Especially ASVS, ATS, and VTS. Any object, audio or video, on a types of DVD-Audio players, withVTS are comprised, respectively, of a DVD-Audio disk is recorded as a pro- mandatory functions specified for each.file for storing the navigation infer- gram stream complying with the The audio-only player (AOP) is notmation (for example, ATSI), a back- MPEG-2 system (ISO/IEC 13818-1). capable of playing back still picturesup file of the information, and one or Fig. 5 gives an example of the rela- and video or moving pictures. Thismore files for recording the object set tionship between the user's view (the would be a high-end audio player or a(for example, ADDS), which is the hierarchical structure in Fig. 2) and the two-channel player of simple construc-collection of the presentation data internal structure not visible to users. A tion, minimally equipped, and priced(objects). This concept is commonly group consists of one or more audio ti- low. The audio portions of a videoincorporated in DVD applications, so des (ATTs), each of which plays back track can be played back if pro-as to make disk authoring flexible one or more contiguous tracks having grammed by the content provider.and to make it easy to reuse objects, the same audio coding mode. In addition to the capabilities of an an-

As shown in the Table 1, the presen- An ATT of audio tracks is translated did-only player, the video-capable audiotation data for audio tracks are recorded into an ATS title (ATS_Tr) in an ATS, player (VCAP) provides playback of still

pictures and videos. It supports still pic-tures attached to audio tracks, contentsin video tracks, and the visual menu.

User's As a memberof the DVD disk fami-view ly, DVD-Video is already on the mar-

ket in the form of video players anddisks. Since video players and video-capable audio players have many thingsin common, we anticipate that manymanufacturers will develop players ca-

Internal pable of playing back both DVD-Videostructure and DVD-Audio disks. The compatible

player, tentatively named "universalplayer," however, is not specified in theDVD-Audio specifications.

Table 2 shows the relationship be-Fig.5. Example of relationshipbetween user view and internal structure,with ATT tween disks and the four types of play-consistingofaudiotracks, ers in termsof playbackcompatibility.

1232 d. Audio Eng. Soc., Vol. 48, No. 12, 2000 December

Table 3. Specifications of audio data in audio object.I PackedPCM (MLP)

CodingMode LinearPCM Compresseddata Sourcedata

Sampling frequency 48 / 96 / 192 kHz 48 / 96 / 192kHz44.1 / 88.2 / 176.4 kHz 44.1 / 88.2 / 176.4kHz

Quantization bits 16 / 20 / 24 bit Compressed 16 / 20 / 24 bit

Bit rate 9.6 Mbit/s max. 9.6 Mbit/smax. 13.824Mbit/smax.

Numberofchannels 6max. 6max.

fs=44.1/ 48 / 88.2 / 96 kHz fs=44.1/ 48 / 88.2 / 96 kHz2max. 2max.

fs=176.4/192 kHz fs=176.4/192 kHz

The contents of video tracks on a vides the best performance consistent However, uncompressed linear PCMDVD-Audio disk are recorded in the with existing and future equipment for audio has some limitations in providingsame data structure as DVD-Video ti- both professional and consumer use super-high-quality audio on the disk,ties and can be played back with DVD- and preserves the transparency of audio which has a finite capacity and transferVideo-compfiant players, data delivered as content to consumers, rate. For example, it is not possible to

As shown in Table 3, a sampling fre- provide the supreme-quality audio (192Audio DataCoding Schemes and quency family of 44.1 kHz is incorpo- kHz, 24 bit, two channels) with a play-Specifications rated in addition to the family of 48 back time longer than 74 minutes on aAs explained previously, a DVD-Audio kHz so as to record existing PCM- 4.7-GB disk. Nor is it possible todisk is composed mainly of audio tracks based digital music without any con- record multichannel audio such as 96and optional video tracks, with their version process and hence without any kHz, 24 bit, six channels at 13.824presentation data recorded as audio ob- loss of quality. Moreover, the sampling Mbit/s, which well exceeds the bit-ratejects and video objects. The specifica- frequency of 192 kHz (176.4 kHz) is limit of 9.6 Mbit/s.tions of the audio data in each object are added to extend the frequency response To solve these problems, a losslessshown separately in Tables 3 and 5. up to around 100 kHz. coding scheme, packed PCM (see part 4

Video tracks are configured in the The highest quality linear PCM an- of the specifications) was adopted as theDVD-Video specifications with some dio specifications are 192 kHz, 24 bit, other mandatory coding scheme. Therestrictions (discussed on page 1230 in and two channels for stereo content, coding algorithm of packed PCM isVideo Tracks), which include a role on and 96 kHz, 20 bit, and five channels Meridian lossless packing (MLP) (seethe channel assignment for linear PCM or 96 kHz, 16 bit, and six channels for Gerzon et al, 1999, and Stuart, et al,audio (discussed later). It is mandatory multichannel audio. In order to accom- 1999). MLP losslessly reduces both thefor linear PCM or Dolby AC-3 coded modate for such new audio parameters, peak bit rate and the average bit rate ofaudio to be contained in each video the maximum bit rate of the audio the source linear PCM audio data andtrack, without any TV-system-oriented stream in an audio object is extended to makes it possible to record high-raterule like MPEG audio of DVD-Video, 9.6 Mbit/s. contents such as 96 kHz, 24 bit, six chan-whichis definedas one of nelsandtoextendtherecordingtime.themandatoryaudiocoding 800 Whilethebit rateof a linearPCM-

modes for TV system _ 700 codedstreamis constant,MLPbasically625/50 only. _ 600 generates a variable bit rate (VBR)Theaudiodata specifica- .~ streamwhosemaximumbitratedoesnot500tions of audio tracks were _ exceed 9.6 Mbit/s. The recording timebuilt based on those of _ 400 canbe calculatedfromtheaveragebitDVD-Videoso as to fully _ 300 ratefor thecodedstream.MLPgenerallymeet the requirementspro- % achievesanaveragecompressionratioof200posedby theISC.As a re- _ about50%(theaveragebit rateortheto-suitof thetechnicaldiscus- 100 tal dataquantityis halved)and offerssion between the DVD 0 , , , _ , , i , , playbacktimeslongerthan74 minutesForum and ISC, linear 0 1 2 3 4 5 6 7 8 9 10 for all audio parameters, Fig. dshowsthePCMwas adoptedasone of Bitrate[Mbps] relation betweenthe bit rate (averagedthe mandatory audio coding Fig. 6. Playback time as a function of bit rate on 4.7- value in the case of MLP) and the play-schemes.LinearPCMpro- GBdisk. back time on a 120-mm, single- _,

J. AudioEng. Soc., VoL48, No. 12, 2000 December 1233

DVD-Audio Specifications

in the same sampling frequency familyTable 4. Channel assignment for audio object of either 48 kHz or 44.1 kHz.

This scalable configuration allowsChannelNumber for a higher bit budget and a longer

0 1 2 3 4 5 playing time compared with the normalconfiguration using identical fs and Qb

mono/stereo 1 C 11 for each channel. Scalable channel con-playback 2 L R figurationcombinedwiththeadoption

3 Lf FIf S of packed PCM lossless compressionwill provide an increased bit budget for

4 Lf Rf Ls Rs much longer playing time. When the5 Lf Rf LFE scalable configuration is not applied,6 Lf Rf LFE S CH_GR2 and CH_GR1 have the same

combination offs and Qb.Lf,Rfweighted 7 Lf Rf LFE Ls Rs LinearPCMin a video object also

8 Lf Rf C offers multichannel configurations of9 Lf Rf C S up to six (5.1)channels,althoughthe

concept of channel group is not ap-10 Lf Rf C Ls Rs plied.For a videoobject,a totalof2411 Lf Rf C LFE configurations are utilized. They con-12 Lf Rf C LFE S tain the configurationscorresponding

to numbers 1 through 13 in Table 4,13 If Rf C LFE Ls Rs and an additional 11 configurations14 Lf Rf C S providing two-channel stereo parts as15 Lf Rf C Ls Rs channels0 and 1, plus multichannel

parts (such as numbers 3 to 13 in TableFront weighted 16 Lf Rf C LFE 4) as channels 2 to 7. The latter config-

17 Lf Rf C LFE S urations,stereoplus multichannel,are18 Lf Rf C LFE Ls Rs incorporatedinstead of the down-mix

method for the stereo playback of audio9. ob ects seeection oft es eiCornerweighted20 Lf Rf Ls Rs ]l C cations).21 Lf Rf Ls Rs C LFE AlthoughDVD-Videospecifications

offer many more channel configura-Channel Channel tions with up to eight channels for sur-Group1 Group2

round use, only 24 configurations arepermitted, to be consistent with theconfigurations for audio objects.

The channel assignment for the cod-layer, single-sided (4.7-GB) disk. The groups, CH_GR1 and CH_GR2, with ing scheme other than linear PCM isplayback time of 74 minutes is achieved each channel group having different defined within each coding scheme.at the bit rate of around 8 Mbit/s. scalable parameters of sampling fre-

quency _) and quantization bits (Qb), a Stereo Playback: Down-Mix MethodChannel Assignment and Scalable total of 21 configurations are defined as and Audio SelectionChannel Configuration in Table 4. One of DVD-Audio's major features isAs shown in Table 4, channel alloca- Scalablility, which means that multichannel audio, which promises totions for audio objects (linear PCM or CH_GR2 can have lower sampling fie- offer a new way of enjoying recordedpacked PCM) are for monaural, stereo, quency and quantization bits than music. However, not all users necessar-and multichannel (Lf, Rf, C, LFE, Ls, CH_GR1, makes it possible to allocate ily have the six-channel audio equip-and Rs). The home theater infrastruc- more information to more important ment at home. DVD-Audio specifica-ture and the requests of the music in- channels in CH_GR1 for an efficient bit tions allow for two-channel stereodustry were taken into consideration in budget. The content provider can choose playback compatible with multichanneldetermining a maximum of six (5.1) the most suitable option among Lf, Rf playback.channels, weighted, front weighted, and comer When the linear PCM of an audio

Basically 13 channel configurations weighted. As with no. 15 in Table 4, a object is played back, the player auto-from monaural to 5.1 channels are pos- combination is possible in which Lf, Rf, matically performs the down mix fromsible. Moreover, since audio object and C are 96 kHz and 24 bit, and Ls and multichannel to two-channel stereo byspecifications have the provision for di- Rs are 48 kHz and 16 bit. It must be not- using the down-mix coefficients pro-viding channels into two channel ed that CH_GR1 and CH_GR2 must be vided by the content provider. Since

1234 d.AudioEng.Soc.,Vol.48,No.12,2000December

each down-mix coefficient (for exam- quired for stereo players, compared as one track having two selections forple, C to L mixed) can be specified in with the conventional method in which playing back.units as fine as 0.2 dB, and a set of the whole channels are once decoded The principal merit of this scheme isdown-mix coefficients for each track and then down-mixed to two channels, that content providers can make thecan differ from that for the others, the This down-mix method effectively stereo mix from the multichannel mas-content provider can program the stereo saves disk space, since a DVD-Audio ter with sound-effect processing suchpresentation best suited for all multi- disk contains only the data for up to six as EQ, reverb, and delay during thechannel contents. This method is called channels, down-mix processing, which wouldsystem-managed audio resource tech- On the other hand, with linear PCM bring more artistic expression into thenique (SMART). in a video object, only channels 0 and 1 content than the simple down-mix

When packed PCM is applied, the from the multichannel data are present- method.down mix is performed during the loss- ed according to the rule defined in This scheme, however, inevitably re-less encoding, not during playback on DVD-Video specifications. Therefore it quires more disk space to record bothplayers. Therefore the down-mixed is recommended that down-mixed two- the multichannel and the two-channel

two-channel signals are compressed channel data be recorded as channels 0 mixes. If saving disk space is a require-into a Lo/Ro-coded substream and and 1 for stereo presentation, using the ment, it is best to apply packed PCMrecorded on the disk together with the channel configuration stereo plus mul- for both mixes. In addition to the selec-other substream conveying the rest of tichannel, mentioned in section 5.2.2 of tion of multichannel and stereo mixes,the channels (C, LFE, Ls, Rs). There- the specifications, the audio selection scheme offers thefore the player only has to extract and The other approach to accommodate selection of stereo and stereo (multi-decode the Lo/Ro-coded substream for multichannel and two-channel music channel and multichannel) with differ-stereo playback. For multichannel play- on a disk is called audio selection, in ent coding schemes.back the player decodes both the which both multichannel and two-chan-Lo/Ro-coded substream and the other nel data are recorded in a track and re- MULTIMED|A SPECIF|CATIONS

substream, and losslessly reproduces ferred to as audio selection 1 (six chan- As developed in section 3 of the speci-the original multichannel signals before nels) and audio selection 2 (stereo). fications, DVD-Audio provides notthe down mix. This scheme greatly re- Although the data are recorded as two only for high-quality pure audio con-duces the computational power re- different audio objects, this is handled tents but also for a variety of value-

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J. Audio Eng. Soc., Vol. 48, No. 12, 2000 December 1235

DVD-Audio Specifications

L

Fig. 7. Configuration of visual menu with additional information.

added contents. The user can have the uration of the visual menu. From the A unit for presenting a still picture innew experience of viewing high-quality main menu page, which is displayed an audio track is called audio still videostill pictures, song lyrics, and other first, the user can select songs (tracks), (ASV) and is composed of one MPEG- 'text-based information while listening pages of liner notes, or a video by acti- 1 or MPEG-2 coded picture and an op-to high-quality audio, vating the corresponding buttons. The tional subpicture and highlight infor-

DVD-Audio has the capability user can open the visual menu, pro- mation to attach buttons on the picture.known as the visual menu, which is ba- grammed by the content provider, with a The presentation data of an audio-sically the same as the title menu de- remote control unit, or the visual menu still-video object (ASVOB) arefined in DVD-Video. The visual menu is automatically presented immediately recorded as an MPEG-2 programis utilized mainly to construct the menu after the playback of a group is finished, stream, like an audio object (AOB) orfor accessing the contents, groups, and when the return menu flag specific to a video object (VOB). All the audio-tracks. It is also suitable for providing the group is set to "Visual menu must be still-video objects used in the audiomoving pictures or still pictures corn- playedback." tracks on a disk (album) are not multi-prising the liner notes, discography, plexed with the audio data in audioand interviews with the artists. Still Pictures objects, but located in an audio-still-

Only one set of the contents for the Although video tracks (video objects) video object set (see ASVS in Tablevisual menu is recorded optionally in can provide still picture images accom- 1). This structure allows for sharingthe audio manager (see Table 1) as a panying the audio presentation, the au- the same audio still videos (ASVs)form of one or more language units, die specifications in this case are limited between multiple tracks and for in-each of which contains the data written to those in Table 5, and the higher speci- creasing the flexibility of disk author-in one language and selectively pro- fications in Table 3 cannot be utilized, ing because audio objects and audio-sented according to the player's lan- Therefore DVD-Audio defines still-pic- still-video objects can be producedguage setting, ture functionality for audio tracks corn- separately.

Fig. 7 gives an example of the config- patible with super high-quality audio. Fig. 8 shows the playback model for

Table 5. Specifications of audio data in video object

Optional Coding ModesCoding Mode Linear PCM Dolby AC-3

MPEG-1 MPEG-2Audio Audio DTS SDDS

Samplingfrequency 48 / 96 kHz 48 kHz 48 kHz 48 kHz 48 kHz

Quantizationbits 16 / 20 / 24 bit Compressed Comp. Comp. Comp.

Bit rate 6.144 Mbit/s 448 kJt/ps 384 kbit/s 912 kbit/s 1536 kbit/s 1280kbit/s

Numberof channels,max. 8 5.1 2 7.1 5.1 7.12-ch stereo

+

6-ch multichannel

1236 J. AudioEng.Soc.,Vol.48, No.12,2000December

are changed is called the ASVU range.Still pictures for audio tracks support

ASVU Range various kinds of presentation functions,which the content provider utilizes selec-

I _V--q+ + _ tivelyaccordingtotheintendeduseofthe

Audio Still Video _ still pictures. Still picture functionality isUnit IA classifiedprimarilyintotwomodesof

in memory _ displaytimingcontrol.Oneis theslide-

(2MB max.)__ /" Audio presentation t---* show mode, in which audio still videosDisplay/ (one Track or plural Tracks) are presented at specified times duringthe audio presentation. The second istiming calledthebrowsablemode,inwhichthe

ASV presentation is independent of theFig. 8. Playback model of audio still videos (ASVs). First ASV is displayed together audio presentation and the user canwith audio presentation; display is maintained until next ASV is displayed, browse through the audio still videos.

There are also two display-orderaudio still videos (ASVs). A set of means that the user can browse through modes for audio still videos: sequential,ASVs to be presented together with one the still pictures. This functionality is in which the content provider specifiesor more audio tracks is called an ASV discussedlater, the order for displaying ASVs, and ran-unit (ASVU), which is preloaded into The maximum size of one ASV unit dom/shuffie, in which the order is gen-the memory of the player before the is 2 MB (2 097 152 bytes), which typi- crated randomly by the player. In sum-start of the audio presentation. Since cally allows for storing 19 MPEG-2 mary, combining the display timingeach andio-still-video object (ASVOB) still pictures. As the resolution and modes and the display order modes, thein the ASV unit is read from the memo- quality of the stored pictures decrease, following four modes are defined:ry, changing the audio still videos does more pictures can be stored in an ASV • Sequential slide-shownot affect the audio presentation at all. unit. The valid range of one ASV unit • Random/shuffle slide-showMoreover, since the control of the dis- in which the audio presentation is not • Sequential browsableplay timing of the ASV is flexible, this interrupted while the audio still videos • Random/shuffle browsable.

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J. Audio Eng. Soc., Vol. 48, No. 12, 2000 December 1237

DVD-Audio Specifications

a longer playback time than the indus-Provider determines the display order of ASVs try norm of 74 minutes by incorporat-

Display '#1 #2 #3 #4 -" ing the lossless coding scheme. Content

order ?Aud_io p nta_tiont_ _ providerscan createany kind of music

with a variety of sound quality in vari-ous configurations on a DVD-Audio

rese I disk,and users can enjoythe musict t _ t withthegreatestsoundqualitythatbest•,.. _,, matches their listening environments.

In addition to the super-high-qualityProvider determines the display timing of each ASV audio contents, DVD-Audio supports

Fig. 9. Conceptual example of sequential slide-show, showing that both display various kinds of value-added contentstiming and order of ASVs are determined by content provider, such as still pictures, moving pictures,

menus, and text information to enrich

Fig. 9 gives a conceptual example of for 15 seconds, the next ASV is dis- the user's audio experience.a sequential slide-show. The display played automatically without interven- Since most of DVD-Audio's specifi-timings and the order of ASVs are pre- don from the user. Specifying "infinite" cations are designed based on the con-determined by the content provider and for the duration means that the dis- cept of DVD-Video, it is possible tobeyond the user's control. Slide-show played ASV is maintained unless the share technical resources in terms ofis best suited for the presentation of user intentionally selects another audio disk authoring and manufacturing andphotos or pictures directly related to the still video. It is also possible to direct player design and manufacturing.audio presentation, such as linked lyrics the player to generate random display DVD-Audio specifications and DVD-or other graphics that need to be syn- durations. Fig. 10 shows an example Video specifications offer some of thechronized with the audio presentation, with a finite duration being specified, best solutions for presenting multime-

With linked lyrics, a picture may Such interactive navigation allows con- dia applications.have multiple lines of lyrics. Each line tent providers to add greater value to ACKNOWLEDGMENTis linked to the audio presentation, the presentation of high-quality audioWhen the user highlights and selects a tracks. The browsable mode is best The contents of this article are basedline or phrase (a button can be used), suited for the presentation of jacket pic- on four technical papers, per courtesythe link is activated to a track or cell of tures, credits, and associated graphic s. of the authors, presented at the 9th Re-the audiopresentation.A cell is a finer gionalConventionof the Audio Engi-presentation unit than a track. Since the CONCLUSIONS neering Society, Tokyo, Japan, 1999synchronization or link between indi- DVD-Audio specifications have been June 23-25: Fuchigami and Kuroiwa;vidual lyrics and the audio is indispens- established to be a global standard of Yamamoto and Sawabe; Otomo; andable, linked lyrics is best implemented the next-generation audio media to pro- Mori, Kozuka, Shinbo and Abe. Thein the slide-show mode. vide consumers with high-quality audio authors wish to thank K. Yamamoto

Fig. 10 gives a conceptual example and a wide variety of contents that fully and T. Sawabe of Pioneer Electronicof the sequential browsable mode. Here meet the requirements from the music Corp., H. Otomo and H. Mimura ofthe content provider chooses to specify industry. DVD-Audio's audio specifi- Toshiba Corp., and Y. Mori, M. Kozu-the default display duration (not the cations offer a superwide range of ka, M. Shinbo, and T. Abe of Mat-timing) of the audio still videos. Thus, stereo music that surpasses convention- sushita Electronic Industrial Co., Ltd.,if the user does not select a new ASV al audio media in sound quality, allow for their kind cooperation during thewithin the default display duration, users to experience new high-quality preparation of this paper. They alsowhich typically could be programmed multichannel surround music, and give thank S. Ueno of JVC for his sup-

Display order#1 #2 #3 #4 # I #2 # l #2 #3 #4 # l

] _ u_l°presenta_i°n tl---_ Audio presentation t---_\

Display duration is determined .,,-'7772Z"_ t _ tby Provider (,_,_i,_n') prev. next homeor generated randomly by Player

Fig. 10.Conceptual example of sequential browsable mode.Left, no user operation occurs. Right, some user operationstochange ASVs occur.

1238 J. Audio Eng. Soc., Vol. 48, No. 12, 2000 December

_DVD-Audio Specifications

port as well as everybody worldwide 1999 June 23-25), preprint H-4, pp. Version 1.01," DVD Forum, Tokyo,who participated in producing the 140 147. Japan (1997 Dec.).DVD-Audio specifications. Y. Mori, M. Kozuka, M. Shinbo, and "DVD Specifications for Read-Only

T. Abe, "Navigation Structure in DVD- Disc Part 3: Video Specifications, Ver-REFERENCES Audio, and Relation with DVD- sion 1.1," DVD Forum, Tokyo, Japan

N. Fuchigami and T. Kuroiwa, "An Video," presented at the 9th Regional (1997 Dec.).Overview of DVD-Audio Format," Convention of the Audio Engineering "DVD Specifications for Read-Onlypresented at the 9th Regional Conven- Society (Tokyo, Japan, 1999 June Disc Part 4: Audio Specifications,tion of the Audio Engineering Society 23-25), preprint H-5, pp. 148-151. Packed PCM: MLP Reference Infor-(Tokyo, Japan, 1999 June 23-25), B.H. Suzuki, "DVD-Audio Specifi- mation, Version 1.0," DVD Forum,preprint H-2, pp. 136-139. cations," in Proc. AES 17th Int. Conf. Tokyo, Japan (1999 Mar.).

K. Yamamoto and T. Sawabe, on High-Quality Audio Coding (1999), M.A. Gerzon, P. G. Craven, J. R."High-Qualityand MultichannelAudio pp. 34-39. Stuart, M. J. Law, and R. J. Wilson,Contents for DVD-Audio," presented "DVD Specifications for Read-Only "The MLP Lossless Compression Sys-at the 9th Regional Convention of the Disc Part 4: Audio Specifications, Ver- tem," in Proc. AES 17th Int. Conf. onAudio Engineering Society (Tokyo, sion 1.0," DVD Forum, Tokyo, Japan High-Quality Audio Coding (1999),Japan, 1999June 23-25), preprintH-3, (1999Mar.). pp. 61-75.pp. 140-143. "DVD Specificationsfor Read-Only J.R. Stuart, P. G. Craven, and M. J.

H. Otomo, "Specifications of Still Disc Part 1: Physical Specifications, Law, "Lossless Compression for DVD-Pictures and Text Informations in Version 1.01," DVD Forum, Tokyo, Audio," presented at the 9th RegionalDVD-Audio format," presented at the Japan (1997 Dec.). Convention of the Audio Engineering9th Regional Convention of the Audio "DVD Specifications for Read-Only Society (Tokyo, Japan, 1999 JuneEngineering Society (Tokyo, Japan, Disc Part 2: File System Specifications, 23-25), preprint H-6, pp. 152-155.

THE AUTHORS

Norihiko Fuchigami received a Toshio Kuroiwa receiveda B.S.de- Bike H. Suzuki graduated with aB.Eng. and M.Eng. degrees from gree in electronicsengineeringfrom bachelor degree in electrical engi-KyushuUniversity,Fukuoka,Japan, Waseda University,Tokyo, Japan,in neering from the TohokuUniversity,in 1987 and 1989, respectively,and 1989.He thenjoinedtheCentralRe- Japan in 1966. Since then he hasthen joined the Victor Company of search and DevelopmentCenter of workedfor JVC on loudspeakeren-Japan, Ltd. From 1989 to 1990 he VictorCompanyof Japan,Ltd., and closure diffraction analysis, roomworkedon the standardizationof the workedon researchintodigitalsignal acousticdesignand measurement.MPEG-1 Audio format. He has also processingfor a high-densityoptical Recordingstudiosfor whichhe pro-workedon the developmentof audio disksystem.Since1995 hehas been vided acoustic design with Samcodingalgorithms,especiallyinterms activein the standardizationof DVD- ToyoshimaincludeAbbeyRoadStu-of a psychoacousticmodel.In recent Videoand DVD-Audiospecifications dios, Townhouse Studios, andyearshehasbeenactiveinstandard- inWG-1 andWG-4of DVD Forumre- MetropolisStudiosin London.Cur-izing DVD-Audio and DVD Audio spectively, rently,he is engaged in the activityofrecording specifications in Working DVD-Audio Format production asGroup4oftheDVDForum. Chairmanof AudioWorkingGroup

WG-4 of DVD Forum.

1240 J. Audio Eng. Soc., Vol. 48, No. 12, 2000 December