New DLS Format Created for MPEG-4 Standard

At the 45th meeting of the Moving Picture Experts Group (MPEG), audio experts reached agreement on a common format for creating sounds with the popular "wavetable synthesis" technique. The agreement merges the best features of different specifications promoted by the MIDI Manufacturers Association (MMA) and Creative Technology Ltd. into a single format. This new format is called Downloadable Sounds Level 2 (DLS-2) and is known within MPEG as the MPEG-4 Structured Audio Sample Bank Format.

The DLS-2 format is an extension of the MMA's DLS-1 format; it includes new features requested by MPEG, Creative, Microsoft, the MIT Media Laboratory, and MMA members. "The agreement on DLS-2 increases consumers' access to high-quality interactive music content," said Tom White, president and chief executive officer of the MMA. "Compatibility among multiple vendors was the compelling reason behind the MMA's DLS Level 1 Specification, and the MMA is very pleased to have had this collaboration with MPEG in establishing a single new standard with an even higher level of performance." The MMA is a nonprofit association which produces standards and recommended practices for musical instruments and digital music devices.

Wavetable synthesis is a popular and widely-used method for creating music in multimedia presentations, video games, and on the Internet. Short samples of recorded sound (wavetables) are accessed with MIDI instructions; this method provides the realism of recorded sound but at a significant savings in file size. Most multimedia PCs use this method for creating sound, and even more powerful versions are used by professional musicians to produce film scores and popular music recordings. The DLS format makes it possible for musicians composing for Internet or CD-ROM applications to use sounds of their own design, rather than limiting their compositions to the 128 General MIDI sounds that are typically available on multimedia computers.

"Microsoft is a firm believer in the value of open standards," said Kevin Bachus, product manager for DirectX at Microsoft. "We made a commitment early on to provide support in the Windows operating system for the DLS format, and are pleased have had MPEG's collaboration in delivering a more advanced DLS standard to hardware manufacturers, software developers and composers. With the DLS support included in the DirectMusic application programming interface, musicians and programmers can easily add interactive music capabilities to applications developed for the Windows operating system."

"At Creative, quality and flexibility of sound synthesis is paramount," said Dave Rossum, founder of E-Mu Systems and chief scientist of Creative Technology Ltd. "We always give the strongest attention to the quality and flexibility possible in sound synthesis. The new wavetable format will provide the best features and sound quality for use by all PC-based and Internet musicians. The advanced capabilities of Creative's popular SoundFonts 2.0 format are included in the new standard. "

The harmonized format is one component of a powerful and flexible suite of tools in MPEG-4 called Structured Audio, contributed for free to MPEG by the MIT Media Laboratory. In MPEG-4, wavetable synthesis can be used in conjunction with general-purpose software synthesis and mixed with compressed vocals or the sounds of natural musical instruments. The resulting soundtracks may be transmitted as part of a virtual-reality experience or used as accompaniment to interactive video presentations on the Internet.

MPEG-4 Structured Audio is based on a powerful sound-description language for very-low-bitrate coding of synthetic music and sound effects and "3-D" positional audio. MPEG-4 was ratified as a Final Draft of International Standard at the meeting in Atlantic City, and will be published in December. For more details on MPEG-4 Structured Audio, please visit sound.media.mit.edu/mpeg4/ .

"MPEG, as part of the international standardization community, is the ideal forum to bring together representatives from industry to arrive at common understandings and to agree on the best technical solutions," said Leonardo Chiariglione, chairman and Convener of MPEG. "Everyone who cares about music synthesis should applaud the forward thinking of the companies involved. We are particularly grateful for the productive relationship with the MIDI Manufacturers Association." MPEG is a subdivision of the International Organisation for Standardisation (ISO) chartered with the development of new standards for audiovisual compression and transmission.

The Downloadable Sounds Level 2 (DLS-2) specification will be available from the MIDI Manufacturers Association in January 1999.