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3.12 Multimedia 3.12-

3.12-1 Text encoding interchange standards 3.12-

3.12 Multimedia. For purposes of this part of the ITSG, multimedia is defined as: "Two or more media types (audio, video, imagery, text, and data) electronically manipulated, integrated, and reconstructed in synchrony." This definition was developed by the Interactive Multimedia Association (IMA). Part 12 covers multimedia data interchange, programming environments and systems, presentation, and multimedia aspects of video and audiographic teleconferencing.

By definition, multimedia encompasses a broad range of media types and associated standards. Because multimedia is an emerging technology, many related standards are industry-based de facto standards or emerging official standards. Therefore, as a general rule, any procurement involving multimedia should proceed with caution in standards selection and ensure that selected standards are compatible. Often, interim solutions may be required to meet immediate mission requirements. Therefore original source materials should always be maintained for archival and re-use purposes.

The first step in selecting and adhering to the right multimedia standards is assuring that end-users, designers, and acquisition staff have a clear vision of what the final product must do. The DOD model for process definition is the Integration Definition (IDEF) process. Through it, process owners and decision makers can visualize how selected technologies will enhance the core operation. Following the process through the steps in the model helps assure sufficient vision, imagination, and scope have gone into the project. This increases the likelihood that the multimedia solution meets as many of the present and planned mission requirements as possible. It also demonstrates when, where, and to what degree multimedia standards apply.

Multimedia standards apply differently according to the types of products or services required and the individual's role in the process. However, regardless of how wide or narrow the frame of reference, understanding the multimedia principles of portability, interoperability, and interchangeability will help achieve the ultimate goal of compatibility to the maximum extent possible.

Portability means software (e.g., a multimedia application or title) can run without regard to system hardware, operating system, mode (stand-alone, network, distributive, mainframe-to-terminal, etc.), or peripheral equipment. Measures of portability attempt to express the ease of operating a piece of software on different automated systems. The more portable the application development environment, the more likely that a favorite application is available to the end-user's favorite platform.

(NOTE: For purposes of part 12, a multimedia title is a finished multimedia production for presentation to an end-user.)

Interoperability is successful interchange of both data and meaning. Application processes interoperate when the output of a given process is successfully acquired and used by other processes. Consider an audiographic teleconference. The goal of the conference is to talk about and make changes to a document that includes text, graphics, and other elements. Assume that the participants have software that can display this document, but that each participant has a different brand of software. If any participant can make changes to the document that are then displayed to all participants, then interoperability exists. However, if a participant must relate desired changes to the conference initiator, who then makes the changes and displays the edited document on the other participants' computers, portability exists but not interoperability.

General-purpose standards to support interoperability are usually complex and comprehensive. Usually such standards rely on other standards and families of related standards to provide interoperability.

NOTE: Throughout Part 12, all tables have abbreviations listed under the column (Standard Type) as follows:

a. National Public Consensus = NPC
b. International Public Consensus = IPC
c. Government Public Consensus = GPC
d. Consortia Public Consensus = CPC
e. Corporate Private Non-Consensus = CPN-C

3.12.1 Multimedia data interchange formats and protocols. Interchange refers to transferring information between processes (applications or services). Interchange can be successful only if both parties to the interchange transaction, sender and receiver, know about the format of the information being interchanged. Interchange can be blind, which means that the information must be self-describing to some extent, or negotiated, which means that sender and receiver carry on a dialogue to determine formats they have in common and can interchange successfully.

Information can be interchanged at several semantic levels. The simplest level we will call a monomedia format or data type. A data type represents one type of information. Multimedia data types of interest include text, vector graphics, raster graphics (still and moving images), and audio. All data types are represented in encoded form. The encoding may be simple (e.g., 7-bit ASCII text) or complex (e.g., Moving Picture Experts Group [MPEG] compression and motion prediction).

Data types may be interchanged directly or embedded in more structured interchange files or data streams. Collections of monomedia objects may be wrapped in a container file, such as Bento (created by Apple and recommended by the IMA). Relationships among the objects in these files, such as synchronization information, may be shown by providing additional information.

Another layer of structuring may be provided by providing a direct mapping onto the file system of an operating system. Such features of file systems as directories, subdirectories, and files may have direct analogues on the transmission media (e.g., tape, floppy disk, or CD-ROM).

Data formats allow interchange of monomedia information. Container file formats allow interchange of information that is more structured and is capable of showing relationships among the data formats. Many data- and container-format specifications contain extra information that permits some meaning to be deduced from the interchange of formats. Currently, most data interchange is accomplished with data formats.

3.12.1.1 Text encoding interchange. Text encodings are methods of defining characters sets as numerical values that are mapped to specific characters. This BSA is a distillation of the Characters and Symbols MLSA.

3.12.1.1.1 Standards. Table 3.12-1 presents multimedia standards for text interchange.

3.12.1.1.2 Alternative specifications. None.

3.12.1.1.3 Standards deficiencies. For character sets, each language needs a programming environment to handle conversion, sorting, and string handling to support proper localization and internationalization.

3.12.1.1.4 Portability caveats. Target presentation systems and viewers may not have the required support for specific text encodings.

A backward incompatible change of ISO 10646 is being prepared. It involved a rearrangement of the code positions for some Korean characters. This will probably be in draft amendment 5 which is expected in 1997. This rearrangement is contrary to the previous policy of the committee.

3.12.1.1.5 Related standards. None.

3.12.1.1.6 Recommendations. ISO 8859 is the predominant character encoding standard used in X Windows and includes multilingual character set standards. ISO 2022 specifies methods of extending the 255-glyph limit of character sets coded by single octets. ISO 10646 allows multiple-byte encodings.

Unicode is a standard for the representation of international character sets. It is ISO 10646 compliant. Unicode uses a unified Han character set to represent Japanese and Chinese characters. A country-specific implementation may be required for each country if this system is used. Unicode should be used for any new systems for which will need large character sets such as those used in foreign languages.

3.12.1.2 Document interchange. (This BSA appears in part 5, Data Interchange, and part 12, Multimedia.) Document interchange standards allow the transfer of formatted documents across a network so they can be reproduced exactly and worked on at their destinations.

3.12.1.2.1 Standards. Table 3.12-2 presents standards for document interchange.

3.12.1.2.2 Alternative specifications. The following specifications are also available:

3.12.1.2.3 Standards deficiencies. There is very little standardization of font names when handling fonts represented by tagged-text data types. However, many systems are attempting font substitution, that is, replacing a specified font with one that is similar, such as substituting TrueType Arial for PostScript Helvetica. Not all tagged text systems are able to specify colored text.

3.12.1.2.4 Portability caveats. At present, portability using ODA/ODIF is limited, because it is not in widespread use or widely available, although SGML is widely available.

3.12.1.2.5 Related standards. The following standards are related to document exchange:

3.12.1.2.6 Recommendations. In keeping with the ongoing shift from literal page appearance to electronic transfer of document content (as exemplified by the electronic commerce and CALS programs) we recommend the use of SGML for document interchange. Alternative standards -Adherence to CALS specifications and standards should be maintained to the maximum extent possible, as use of CALS provides maximum interoperability. In the event that a CALS standard cannot convey the technical information of a particular application, only then is the use of a non-CALS standard justified. On March 25-26, 1993, the Defense Information Systems Agency (DISA) convened a Document Interchange Symposium. The symposium featured a panel of ODA and SGML experts to deliberate on SGML/ODA issues. The panel reached the following conclusions:

In addition to the panel's conclusions, it should be noted that NIST has decided not to develop a FIPS for ODA. The DOD SGML standard (MIL-PRF-28001) is based on ISO 8879. MIL-HDBK-28001 for SGML is being developed.

For documents intended for distribution on the Internet, particularly the World Wide Web, HTML should be used. HTML is a document type definition (DTD) of SGML for Internet documents.

Adobe PDF is being used frequently in DOD for formatting documents where revisions are not required. However, PDF suffers by the fact that it has not yet been endorsed by an open consensus standards body. Efforts need to be taken to move PDF from the de facto, proprietary, realm to be an open standard.

3.12.1.3 Font information interchange. (This BSA appears in part 5, Data Interchange, and part 12, Multimedia.) Font information interchange standards specify the encoding of font resource information for use in document processing environments. Font interchange deals with the exchange of character fonts, such as Times Roman or Helvetica, and related information as opposed to simple exchange of character encodings, which do not include font information.

3.12.1.3.1 Standards. Table 3.12-3 presents standards for font information interchange.

3.12.1.3.2 Alternative specifications. Alternative specifications include TrueType and PostScript.

3.12.1.3.3 Standards deficiencies. There is and will be very little standardization of font names, because of copyright concerns. None of the existing font interchange standards accurately enable font substitution. However, many systems are attempting font substitution, that is, replacing a specified font with one that is similar, such as substituting TrueType Arial for PostScript Helvetica.

No standard exists for three-dimensional font families, although such text is becoming popular in display text applications, such as advertising and presentations.

3.12.1.3.4 Portability caveats. Target presentation systems and viewers may not have the required fonts to construct the called-for text in a presentation system. Font substitution may result in an unexpected text presentation. Outline font geometry also can be represented as two-dimensional graphics geometry, which eliminates the need to support a specific font on a target platform.

3.12.1.3.5 Related standards. Standards related to font information interchange standards are:

a. ISO 8632: Computer Graphics Metafile (CGM)
b. X Logical Font Description (see part 3)
c. PostScript Level 2 (starting to be used for colored text)

3.12.1.3.6 Recommendations. If CGM is being used, then ISO 8632-1 DAM 3 also is needed for font information exchange along with ISO 9541. The ISO 9541 specifies the architecture and format for various shape descriptions to be used in document processing environments that recognize Abstract Syntax Notation (ASN).1 or SGML parsing algorithms. ISO 9541 uses Adobe System's PostScript Type-I font technology and file formats. The ISO 9541 is recommended for font information exchange.

For some applications, such as view-only kiosks and presentations, convert text to a graphics format to avoid unknown font resource issues. Use fonts that are in common usage for cross-platform work.

3.12.1.4 Printer data interchange. Printer data interchange is performed by using page description languages to describe a page to be printed so the printer processor can convert the representation directly into a page image for any printer.

3.12.1.4.1 Standards. Table 3.12-4 presents standards for display text interchange.

3.12.1.4.2 Alternative specifications. The following de facto specifications are available:
a. Adobe: PostScript and Display PostScript
b. Hewlett-Packard: Hewlett-Packard Page Description Language (HPDL)
c. Xerox: Interpress

3.12.1.4.3 Standards deficiencies. Deficiencies in the existing standards are unknown.

3.12.1.4.4 Portability caveats. ISO 10180, Standard Page Description Language (SPDL), combines the best of Adobe PostScript and Xerox Interpress, along with enhancements and extensions developed by ISO. However, it is not a superset of the PostScript and Interpress page description languages. The inclusion of parts of each vendor's page description, as well as the ISO extensions, render it incompatible with either PostScript or Interpress.

Although it is a proprietary standard, EPSF is widely supported for importation of display text. However, care should be taken to ensure that tools used to deliver titles support importation of EPSF. Many raster image formats are candidates for this purpose.

3.12.1.4.5 Related standards. No standards are related to page description exchange standards.

3.12.1.4.6 Recommendations. If specifying SPDL in a procurement, the specification of a converter box that converts formats such as PostScript, Interpress, or HPDL to SPDL is recommended. SPDL is a standard with no commercial following. The proprietary specifications, such as PostScript and PDF, are dominant. If used, EPSF or PDF should be considered as an interim solution only until a public standard is available. Adobe PDF is being used frequently in DOD for formatting documents where revisions are not required. However, PDF suffers by the fact that it has not been endorsed by an open consensus standards body.

3.12.1.5 Two-dimensional graphics interchange. Two-dimensional graphics interchange standards deal with computer graphics that are represented by geometric encoding as opposed to images that are represented as bitmaps.

3.12.1.5.1 Standards. Table 3.12-5 presents multimedia standards for two-dimensional graphics interchange.

3.12.1.5.2 Alternative specifications. None.

3.12.1.5.3 Standards deficiencies. Some features are added to PHIGS implementations to compensate for perceived deficiencies in the standard.

3.12.1.5.4 Portability caveats. In 2 1/2-dimensional work where front-to-back ordering of graphical objects is important, the order may be lost when converting from an application program to an interchange format.

Most implementations of PHIGS provide extra features that are not part of the PHIGS standard and often are unnecessary for typical graphics development. These features must be avoided if possible, since unique features limit portability.

3.12.1.5.5 Related standards. The following standards are related to two-dimensional graphics interchange:

3.12.1.5.6 Recommendations. ISO 8632 CGM (MIL-PRF-28003A, MIL-STD-2301, FIPS 128-1) and PHIGS/PHIGS+ (FIPS 153, ISO 9592) are recommended. PHIGS standards should be used without nonstandard features. PHIGS supports both two- and three- dimensional graphics. GKS functionality is totally subsumed and extended by PHIGS.

3.12.1.6 Three-dimensional graphics interchange. Three-dimensional graphics are typically used for CAD/CAM and CAE applications. The interchange is used to directly convey from computer to computer the physical design and shape characteristics of an object or model. However, three-dimensional graphics are becoming more popular in many multimedia applications.

3.12.1.6.1 Standards. Table 3.12-6 presents multimedia standards for three-dimensional graphics interchange formats.

3.12.1.6.2 Alternative specifications. None.

3.12.1.6.3 Standards deficiencies. IGES does not handle all interfaces between the data exchange specifications and external components, such as the interface between the product data specification and numerically controlled machining tools. IGES does not cover the complete life cycle of manufactured products. It addresses only the specification of products and not the manufacturing process relationships. The DOD/CALS IGES standard is preferred for engineering drawings, electronics, and numerical control. The standard is optional for technical manual illustrations.

Some features are added to PHIGS implementations to compensate for perceived deficiencies in the standard.

3.12.1.6.4 Portability caveats. Most implementations of PHIGS provide extra features that are not part of the PHIGS standard and often are unnecessary for typical graphics development. These features must be avoided if possible, since unique features limit portability.

3.12.1.6.5 Related standards. The following standards are related to three-dimensional graphics interchange:

3.12.1.6.6 Recommendations. PHIGS (FIPS 153, ISO 9592) should be used as appropriate. PHIGS includes language bindings for C, FORTRAN, and Ada. PHIGS supports both two- and three- dimensional graphics. GKS-3D functionality is totally subsumed and extended by PHIGS.

3.12.1.7 Animated graphics interchange. Animated graphics include two- and three-dimensional graphics that are presented as motion sequences. The motion is generated internally by a computer system. This differs from motion images, which translate motion captured with a camera for computer display.

3.12.1.7.1 Standards. Table 3.12-7 presents multimedia standards for two- and three- dimensional animated graphics interchange.

3.12.1.7.2 Alternative specifications. None.

3.12.1.7.3 Standards deficiencies. No IPC, NPC, or GPC standards exist for two-dimensional animated graphics. No standards exist for three-dimensional graphics.

3.12.1.7.4 Portability caveats. Exchanging animation across applications and platforms is not well supported.

3.12.1.7.5 Related standards. None.

3.12.1.7.6 Recommendations. If two-dimensional animation is required, the CPN-C standards above should be considered as interim solutions only. Autodesk Flick Files (FLI & FLC) are the only interchange files aimed solely at two-dimensional animated graphics. The two formats differ in resolution. FLI files support 320 x 200 while FLC files are resolution-dependent, although they commonly resolve to 640 x 400.

3.12.1.8 Still image interchange. Still images are images, such as photographs, that are described by bitmaps, as opposed to vector graphics which are described with geometric notation.

3.12.1.8.1 Standards. Table 3.12-8 presents multimedia standards for still image interchange.

3.12.1.8.2 Alternative specifications. Photo CD has five variations of CD formats announced, including one for the medical industry. Many proprietary image formats exist.

3.12.1.8.3 Standards deficiencies. Not all standards can handle the interchange of calibrated color information. Notably, RGB formats are usually unreferenced as to the colorimetric definition of pure red.

Exchanging JPEG images across different implementations can lead to slightly inconsistent images when compared one-for-one with the original. Round-off errors in internal arithmetic are not all the same.

No standard algorithm exists for the reduction of color spaces from 24 to 16 to 8 to 4 bits. Different platforms handle color degradation differently.

3.12.1.8.4 Portability caveats. Even if calibrated color is included with the image, not all applications or platforms can handle the specifications. Some low-end pre-press systems are becoming color-literate. Photo CD does handle calibrated color information.

Because approval of ISO 12087 is so recent, implementations may be limited.

Adobe PDF is being used frequently in DOD for formatting documents where revisions by the end-user are not required.

3.12.1.8.5 Related standards. The following standards and types of standards are related to still image interchange:

CGM includes support for bit-mapped images, although it is seldom used for still image interchange.

3.12.1.8.6 Recommendations. JPEG (MIL-STD-188-198A, ISO 10918) should be used for most applications involving compressed still images. Although JPEG includes lossless compression, virtually all JPEG images are created using lossy compression. This means that information is lost when the image is compressed. Source images, prior to compression, should be maintained.

JPEG supports multiple levels of lossy compression. The degree of compression influences the amount of information lost and image quality upon decompression. Compression levels should be tailored to image quality requirements. While lossy JPEG images typically display at high quality on computer monitors, the quality may be somewhat diminished on hardcopy output devices such as high-resolution color printers.

MIL-PRF-28002B should be used in a CALS environment, and when needed, supplemented by NIST IR 88-4017 (tiling). Tiling and compression are desirable for very large still images. This version (MIL-PRF-28002B) supports raster data.

If the compression scheme defined in MIL-STD-2500A is specified in a procurement, a migration strategy to JPEG should be required. MIL-STD-2500A supports ITU-T Group III compression while CALS supports Group IV only. Use the NITFS compression standards or CALS compression standard, as applicable.

ISO 11544 (JBIG) should be considered when lossless image compression of black and white images is required.

ISO/IEC 12087 is the only IPC standard for still-image APIs. This standard should be used if available implementations can meet mission requirements.

Select aspect ratios and resolutions equal to or greater than those available on target platforms, to protect against new display sizes and resolutions. Source images should be maintained for archival and reuse purposes.

3.12.1.9 Motion video interchange. Motion video interchange includes standards for motion video and associated audio. Animation (3.12.1.6) and live video-audio exchange through video teleconferencing (VTC) (3.12.5) are not included.

3.12.1.9.1 Standards. Table 3.12-9 presents multimedia standards for motion video interchange.

3.12.1.9.2 Alternative specifications. None.

3.12.1.9.3 Standards deficiencies. Animation, synchronization, and degradation control are not well supported in any of the current digital-video environment.

3.12.1.9.4 Portability caveats. The ability of many platforms to display motion video is limited by platform performance. Full-screen, full-motion video usually requires special decompression hardware. Therefore, motion video, especially video that uses software decompression, should use the minimum image size and frame rate required.

NTSC is the U.S. standard for analog television resolution. PAL is a common European standard. SECAM is used in France, Eastern Europe, parts of Africa, and the Middle East.

Although MPEG 1 is rapidly emerging as the standard for computer-based motion video, especially from CD-ROM, decoding MPEG 1 at reasonable image sizes and frame rates requires special hardware assistance. Therefore, MPEG 1 should not be considered portable to legacy systems that do not include MPEG 1 decompression hardware. It is expected that many future computer systems will include MPEG 1 hardware.

MPEG 1 provides for a wide range of video resolutions and data rates but is optimized for single and double-speed CD-ROM data rates (1.2 and 2.4 Mbits/s). With 30 frames per second video at a display resolution of 352 x 240 pixels, the quality of compressed and decompressed video at this data rate is often described as similar to VHS recording. MPEG 1 is frequently used in applications with limited bandwidth, such as CD-ROM playback or Integrated Services Digital Network (ISDN) videoconferencing.

MPEG 2 is designed for the encoding, compression, and storage of studio-quality motion video and multiple CD-quality audio channels at bit rates of 4 to 6 Mbits/s. MPEG 2 has also been extended to cover HDTV.
Programming models are generally in a state of flux, especially at the operating system level. As a result, any code development will probably not port, especially if performance advantages are taken in the imaging, audio, and video areas. QuickTime and Video for Windows are currently available for both Apple System 7 and Microsoft Windows.

3.12.1.9.5 Related standards. The following standards are related to motion video:

a. ISO 10918 (JPEG)

JPEG is used for motion video in non-linear editing systems with proprietary decompression hardware. It is preferred for such systems because each frame is compressed in isolation, allowing direct access to and editing of individual frames. However, ISO 10918 does not include motion specifications.

3.12.1.9.6 Recommendations. MPEG 1 (ISO 11172) is the emerging motion video standard for computer systems and should be used for distribution to systems that include MPEG 1 decompression hardware. For distribution to legacy systems that do not include MPEG 1 hardware, software solutions, such as Microsoft Audio Video Interactive (AVI), should be considered as interim solutions.

MIL-STD-1379D should be used for interactive training delivered on level-3 laserdisc systems using the MS DOS operating system.

MPEG 2 (ISO 13818) is optimal for a variety of data rates ranging from 3 to 10 Mbits/s and higher. It is expected to be used in the cable industry's planned 500-channel systems and for the emerging Video CD technology.

Maintain original video for archival and re-use purposes.

3.12.1.10 Digital audio interchange. Digital audio, also called sampled audio, consists of information that is recorded as digital samples that are played back directly by digital-to-analog conversion.

3.12.1.10.1 Standards. Table 3.12-10 presents multimedia standards for digital audio interchange.

3.12.1.10.2 Alternative specifications. Many popular sound cards support other formats, such as 2- and 4-bit PCM.

3.12.1.10.3 Standards deficiencies. No uniform timing information is carried with most audio interchange formats. Thus synchronization of multiple audio streams is inherently difficult. Also, sound clips may have to be retimed to SMPTE time codes when producing broadcast video output.

3.12.1.10.4 Portability caveats. Apple sampling rates deviate slightly from the values given in the table because of internal clock rates. Therefore, mixing of audio played back from two different platform types is difficult. This is true even among the same kinds of platforms because CPU clocks and sampling clocks on sound boards can vary widely.

The IMA's Recommended Practices for Enhancing Digital Audio Compatibility in Multimedia Systems is a set of audio formats that are guaranteed to be supported on any IMA audio-compliant platform. These formats are required to provide baseline digital audio cross-platform support to satisfy a range of audio quality and data bandwidth requirements. Although the recommended practice has gained industry support, many manufacturers use proprietary ADPCM compression algorithms.

SoundBlaster VOC format is used mainly in Microsoft MS-DOS applications. This is the dominant de facto standard for such applications.

3.12.1.10.5 Related standards. The following standards are related to digital audio interchange standards.

a. Microsoft AVI
b. Apple QuickTime 1.5
c. Apple Bento container format

3.12.1.10.6 Recommendations. MPEG 1 audio is not a single compression algorithm but a family of three audio encoding and compression schemes called MPEG-Audio Layer-2, and Layer-3, all three of which are hierarchically compatible. The audio compression schemes are lossy, but they can achieve perceptually lossless quality.

MPEG 2 audio is intended to encode up to five full bandwidth channels and additional low-frequency enhancement channel, and up to seven commentary or multilingual channels.

Procurements concerned with digital audio should proceed with care. Many important standards for digital audio are proprietary standards.

3.12.1.11 Encoded audio interchange. Encoded audio consists of audio that is described by a language that is interpreted on playback. Encoded audio is typically used for synthesized music.

3.12.1.11.1 Standards. Table 3.12-11 presents multimedia standards for encoded audio interchange.

3.12.1.11.2 Alternative specifications. None

3.12.1.11.3 Standards deficiencies. No IPC, NPC, or GPC standards exist for encoded audio. Synchronization and degradation control are not well supported in any of the current environments.

3.12.1.11.4 Portability caveats. Programming models are generally in a state of flux, especially at the operating system level. As a result, any code development will probably not port, especially if performance advantages are taken in the imaging, audio, and video areas.

3.12.1.11.5 Related standards. None.

3.12.1.11.6 Recommendations. Although MIDI is a CPC standard, it is widely supported by industry. Given the near universal support for MIDI, it is unlikely that an alternative will make inroads unless the underlying technology changes. If synthesized music or sound effects are needed, MIDI is recommended as an interim solution until an IPC, NPC, or GPC standard is available.

Maintain original audio for archival and re-use purposes.

3.12.2 Multimedia programming systems. A programming system is defined to be an application or platform that is intended to encompass all the necessary support to produce or playback a broad range of multimedia titles.

3.12.2.1 Programming platforms. Programming platforms are computer systems designed to include necessary facilities for developing and displaying multimedia titles.

3.12.2.1.1 Standards. Table 3.12-12 presents standards for programming platforms.

3.12.2.1.2 Alternative specifications. Available alternative solutions include various proprietary computer platforms, such as Silicon Graphics development computers.

3.12.2.1.3 Standards deficiencies. No IPC, GPC, or NPC standards exist for the specification of multimedia programming platforms.

The original MPC specification is insufficient for most modern multimedia applications.

All systems are struggling with synchronization accuracy and control of digital data streams, both from the specification and implementation points of view.

Some platform specifications are minimal and too incomplete to guarantee interoperability or portability. Little certification work is underway to guarantee compliance to any of these.

3.12.2.1.4 Portability caveats. Byte alignment of native data types can be a problem when moving between platforms.

3.12.2.1.5 Related standards. None.

3.12.2.1.6 Recommendations. Platforms should be tailored to mission needs. CD-I, which is aimed at the consumer market, is not recommended.

3.12.2.2 Authoring languages. Authoring languages are languages that are specifically designed for the development of multimedia applications and tools. They may be interpreted or compiled on target platforms.

3.12.2.2.1 Standards. Table 3.12-13 presents standards for authoring languages.

3.12.2.2.2 Alternative specifications. Other authoring and scripting languages are available. Many full-featured commercial authoring systems are available, some of which support multiple platforms.

3.12.2.2.3 Standards deficiencies. Deficiencies in the existing specifications are unknown.

3.12.2.2.4 Portability caveats. Portability problems with the existing specifications are unknown.

3.12.2.2.5 Related standards. None.

3.12.2.2.6 Recommendations. HyTime (ISO 10744) is the only IPC standard available for multimedia authoring languages. It should be used if suitable for specific title development.

3.12.2.3 Interchange media. Interchange media are designed to deliver finished multimedia titles to a broad range of platforms.

3.12.2.3.1 Standards. Table 3.12-14 presents standards for supporting interchange between platforms.

3.12.2.3.2 Alternative specifications. No other specifications are available.

3.12.2.3.3 Standards deficiencies. ISO 9660 does not support long filenames such as those used on UNIX systems.

3.12.2.3.4 Portability caveats. The IMA Recommended Practice for Data Exchange has only recently been published. Therefore, it is not yet broadly supported. It is designed to be a platform- and content-neutral recommendation for the exchange of multimedia data for content and title developers.

3.12.2.3.5 Related standards. The following standards are related to CD-ROM:

3.12.2.3.6 Recommendations. ISO 9660 and 10149 should be used for all CD-ROM applications. ISO 9660 describes the logical structure of information on a CD. ISO 10149 describes the physical structure of the CD. In addition, DISA's Department of Defense CD-ROM Requirements and Guidelines, which gives DOD labeling and security requirements along with other information, should be followed.

MHEG (ISO 13522) will define an interchange format for real-time multimedia information interchange. Its goals are platform independent interchange of interactive multimedia content, robust time-space composition and synchronization, real-time interchange, and incorporation of arbitrary monomedia formats.

Use of high-capacity compact discs (MM-CD and SD) should be avoided until a single standard has been agreed upon. Even after agreement, use should be considered carefully because portability will not be available for legacy systems that do not support these discs. An agreement to produce a single standard was announced at the time of this writing.

3.12.3 Multimedia presentation. Presentation standards deal directly with representational issues of information and output devices that convert digital information to human information. Graphical user interfaces are covered in detail in part 3 of the ITSG and are not included here.

3.12.3.1 Text presentation. Text presentation deals with displaying formatted text and documents to appear to the viewer in the way the author intended. It includes both the layout and typeface of the text.

3.12.3.1.1 Standards. Table 3.12-15 presents standards for text presentation.

3.12.3.1.2 Alternative specifications. Viewers are available for some commercial applications, such as Microsoft Word and FrameMaker.

3.12.3.1.3 Standards deficiencies. No approved public standards exist for text presentation.

3.12.3.1.4 Portability caveats. TrueType is limited to Microsoft Windows.

3.12.3.1.5 Related standards. HTML is related to text presentation.

3.12.3.1.6 Recommendations. SPDL deals with text presentation. These standards add formatting information to SGML for the presentation of electronic documents. Adobe PDF supports interchange of documents including graphics among Apple, IBM PC, and UNIX systems. A document is simply printed to Acrobat, which produces an interchange file. The Acrobat reader is available at no charge. Adobe Acrobat should be considered as an interim solution. PDF is used frequently but suffers by the fact that it has not been endorsed by an open consensus standards body. Efforts need to be taken to move PDF from the de facto, proprietary, realm to be an open standard.

HTML is a DTD of SGML. It does not as rigidly define the appearance of HTML-tagged documents as does SPDL or PDF.

3.12.3.2 Graphics presentation. Graphics presentation standards deal with interfaces to graphics display devices and environments for the presentation of graphics and related multimedia objects. Note that in this instance, graphics presentation includes raster and vector graphics.

3.12.3.2.1 Standards. Table 3.12-16 presents standards for graphics presentation.

3.12.3.2.2 Alternative specifications. None.

3.12.3.2.3 Standards deficiencies. No approved IPC, GPC, or NPC standards exist for graphics presentation. Strict adherence to correct presentation and output standards will require color calibration equipment.

3.12.3.2.4 Portability caveats. Graphics portability is generally achieved by data interchange, not by uniform cross-platform display standards. Source material may be visually impaired through use of low quality displays. Vector and raster graphics that require high resolutions and large color spaces will be less portable.

3.12.3.2.5 Related standards. None.

3.12.3.2.6 Recommendations. There is no recommendation at this time.

3.12.3.3 Color definition. (This BSA appears in part 5, Data Interchange, part 12, Multimedia, and part 13, Human Factors.) Color definition deals with establishing a reference base for identifying colors to aid in the matching and exchange of color. Color definition standards apply to defining color in general, and not only to color definition for information technology systems.

3.12.3.3.1 Standard. Table 3.12-17 presents standards for color definition.

The CIE (International Commission on Illumination) is the principal international standards writing body for agreements for color, vision, and illumination. Under ANSI, four bodies work on color-related standards. ANSI X3 works on office document automation and information systems. ANSI IT8/CGATS is concerned with graphic arts. ASTM deals with color metrology and standard practices, and SMPTE handles standards for color television and color monitors.

ANSI's Committee for Graphic Arts Technology Standards (CGATS) has eight subcommittees working on topics such as materials handling, process control, and color data definition. NPESA is the National Printing Equipment and Supply Association.

3.12.3.3.2 Alternative specification. The following alternative specifications are also available:

3.12.3.3.3 Standard deficiencies. Comparison of color defined by the existing standards assumes identical viewing conditions. There are no standards directly addressing comparisons across viewing environments, although models are being worked on. Strict adherence to correct presentation and output standards will require color calibration equipment.

3.12.3.3.4 Portability caveats. Translation of color from one color definition system to another can be difficult and is only an approximation at best. There are three different color definitions from the CIE. They are the CIEXYZ tristimulus values, and the CIELAB and CIELUV color spaces. These standards have existed for a long time and are seen as the common basis for any future unifying definitions.

There are also the problems of color matching. For example, of 1012 Pantone colors for coated paper, 70 cannot be reproduced in the CMYK definition. CIEXYZ is useful in comparing colors under identical viewing conditions. CIEXYZ has a rigorous definition and by itself does not necessarily constitute a complete color specification. CIEXYZ is a standardized set of primaries which are not physically realizable but can match all possible colors with entirely positive tristimulus values. A new form of color definition is emerging, known as high-fidelity color. The idea behind high-fidelity color is the use of five to seven different colors in the printing process to widen the range of colors that can be printed. Two such models that have appeared are the Kupper set which increases the number of printed colors in the blue region by 80%, and the VSF model which provides better performance in deep red and green colors. These processes are very non-standard and should be avoided at present.

Common systems typically do not support colorimetric calibration.

3.12.3.3.5 Related standards. The following types of standards are related to standards for the definition of color:

a. color matching standards
b. color data exchange standards
c. color use standards
d. style guide standards

3.12.3.3.6 Recommendations. The approved standards in this section are recommended where they are applicable. Maintain original copies of source material so that revisions can be produced for next generation systems that will allow the inclusion of calibration information.

3.12.3.4 Audio presentation. Audio presentation standards deal with interfaces for audio playback.

3.12.3.4.1 Standards. Table 3.12-18 presents standards for audio presentation.

3.12.3.4.2 Alternative specifications. None.

3.12.3.4.3 Standards deficiencies. No IPC, GPC, or NPC standards exist for audio presentation. Strict adherence to correct display and output standards will require audio calibration equipment.

3.12.3.4.4 Portability caveats. Source material may be aurally impaired through use of low-quality amplifiers and speakers. Calibration information that allows a user to correctly set audio levels at the beginning of a title can substantially enhance a presentation.

3.12.3.4.5 Related standards. None.

3.12.3.4.6 Recommendations. Maintain original copies of source materials for re-use when IPC, GPC, and NPC standards become available.

3.12.3.5 Monitors. Monitor standards specify the electrical and display characteristics of computer and television monitors.

3.12.3.5.1 Standards. Table 3.12-19 presents standards for monitors.

3.12.3.5.2 Alternative specifications. None.

3.12.3.5.3 Standards deficiencies. Strict adherence to correct display and output standards will require audio and color calibration equipment.

3.12.3.5.4 Portability caveats. Source material may be visually impaired through use of low quality monitors. Calibration information that allows a user to correctly set monitor levels at the beginning of a title can substantially enhance a presentation.

3.12.3.5.5 Related standards. None.

3.12.3.5.6 Recommendations. Use the established standards given above for computer and television monitors. Avoid development for high-definition television, which is now a formative technology.

3.12.3.6 Embedded time codes. Embedded time codes provide timing information within data streams. They are necessary for proper synchronization in the presentation of multimedia.

3.12.3.6.1 Standards. Table 3.12-20 presents standards for embedded time codes.

3.12.3.6.2 Alternative specifications. Proprietary timing and synchronization control codes are used in some environments.

3.12.3.6.3 Standards deficiencies. None.

3.12.3.6.4 Portability caveats. None.

3.12.3.6.5 Related standards. None.

3.12.3.6.6 Recommendations. Use SMPTE 262M.

3.12.4 Video and audiographic teleconferencing. Video teleconferencing is the live transmission of audio and video over a network among two or more users. Audiographic teleconferencing (AGT) lets conference participants manipulate documents and other data collectively with accompanying real-time audio. Many VTC and AGT standards deal with audio/video network services. Only those standards directly related to multimedia data formats are presented below. Transmission protocols, transfer protocols, and security standards are not included.

3.12.4.1.1 Standard. Table 3.12-21 presents standards for video and audiographic teleconferencing.

3.12.4.1.2 Alternative specification. ISO and the ATM Forum are working on standards for high-bandwidth teleconferencing, especially over ATM networks.

3.12.4.1.3 Standard deficiencies. None of the ITU teleconferencing standards work well over Ethernet and TCP/IP networks because of bandwidth limitations.

3.12.4.1.4 Portability caveats. Portability problems with the existing standards are unknown.

3.12.4.1.5 Related standards. MPEG1 (ISO/IEC 11172) and MPEG2 (ISO/IEC 13818) are related to video and audiographic teleconferencing. Various ITU H, G, and T series standards are related to architecture, equipment, transmission protocols, transfer protocols, and security.

3.12.4.1.6 Recommendations. MIL-STD-188-331 and MIL-STD-188-331A have been superceded by the Industry Profile for Video Teleconferencing, VTC001-Rev. 1, which is mandated for DOD by the OASD. Because of differences in network bandwidths and transmission limitations, video and audio standards should be chosen to fit individual VTC system capabilities. For example, ITU G.711 should be used for narrow-band speech, while G.722 should be used for wide-band speech. FIPS PUB 178-1 will replace the VTC001 profile, but is still in draft at this writing.