4.8G Portable MP3 Player

[Xorian] writes "There's a new portable mp3 device called the Personal Jukebox. Apparently, this is the result of a research effort from Compaq's Systems Reserach Center (one of the two Compaq research groups that developed the Itsy). The kicker is that it's supposed to be able to store about 100 CDs worth of music (it's got a a 4.8 GByte hard disk) and have 10 hours of battery life yet fit in your jacket pocket. No word on pricing yet though. "

Comments

Re:Mp4's?

[Eric_Scheirer]

The MPEG-4 Audio standard is done. It was finished at the October 1998 MPEG meeting and is now "out for ballot", which means the various countries that are members of ISO vote to approve it (countries have had several chances to suggest changes, so it's unlikely to be disapproved). After formal ballot approval, it goes to ISO for publication, and then you can buy it. It will likely be available in final form before the end of the year.

The "reference software" (slow, user-hostile code to demonstrate how the standard is supposed to work) was completed in August and the source is available as part of the spec. Non-MPEG organizations are already building tools for user-friendly use of the standard.

The whole MPEG-4 Audio standard (not including Video or Systems) is about 1200 pages long. It is formally ISO 14496-3:1999 and is divided into 6 Sections:

• 1. Introduction and Overview
• 2. Parametric Speech coding
• 3. CELP Speech coding
• 4. General Audio (AAC/TwinVQ merger)
• 5. Structured Audio (audio synthesis)
• 6. Text to Speech Interface

The part that is most like MP3 is Section 4. Section 4 enables music and other wideband audio coding from 16 kbps to 64 kbps/channel. At the high end, the quality is nearly transparent -- most listeners will not be able to tell the difference between the coded and the original signal. MPEG-4 GA at 96 kbps (stereo) gives about the same quality as MP3 at 192 kbps (stereo) -- thus, files are half as big for the same quality.

There are no "layers" in MPEG-4 Audio.

Some of the sections of the standard (2, 3, 4) are protected by patents and cannot be freely implemented. Section 5 is not protected by patents and can be freely implemented without paying license fees.

Here is the hype from the beginning of Section 1:

ISO/IEC 14496-3 (MPEG-4 Audio) is a new kind of audio standard that integrates many different types of audio coding: natural sound with synthetic sound, low bitrate delivery with high-quality delivery, speech with music, complex soundtracks with simple ones, and traditional content with interactive and virtual-reality content. By standardizing individually sophisticated coding tools as well as a novel, flexible framework for audio synchronization, mixing, and downloaded post-production, the developers of the MPEG-4 Audio standard have created new technology for a new, interactive world of digital audio.

MPEG-4, unlike previous audio standards created by ISO/IEC and other groups, does not target a single application such as real-time telephony or high-quality audio compression. Rather, MPEG-4 Audio is a standard that applies to every application requiring the use of advanced sound compression, synthesis, manipulation, or playback. The subparts that follow specify the state-of-the-art coding tools in several domains; however, MPEG-4 Audio is more than just the sum of its parts. As the tools described here are integrated with the rest of the MPEG-4 standard, exciting new possibilities for object- based audio coding, interactive presentation, dynamic soundtracks, and other sorts of new media, are enabled.

Best regards,

-- Eric Scheirer
Editor, ISO 14496-3 (MPEG-4 Audio)

More info: http://sound.media.mit.edu/mpeg4/audio