Bluetooth tweaked for consumer audio/video apps

By
iApplianceWeb
(06/21/02, 11:47:57 AM EDT)

AMSTERDAM, Netherlands - Bluetooth technology will seep from its mobile communications niche into consumer electronics products in 2003 thanks to the imminent arrival of audiovisual profiles, according to several industry sources at the recent Bluetooth Congress here.

Ruud van Bokhorst, chairman of the Bluetooth Special Interest Group's AV working group, said the recent completion of the Advanced Audio Distribution Profile and AV Control Profile will lead to Bluetooth popping up soon in equipment like Walkman-style products, hi-fi audio headsets and speakers, and CD players. Meanwhile, the AV working group is hammering out its Video Distribution Profile and is "almost ready" with a Video Conferencing Profile, said van Bokhorst, who is senior director of the connectivity program office at Philips Components.

Distribution profiles for advanced audio and video are much needed for Bluetooth audio/video streaming applications, while the AV Control Profile defines transport protocols necessary to send commands such as stop and play. The Video Conferencing Profile, meanwhile, will be used for third-generation mobile phones.

Bluetooth developers see audio/video applications as "the next big bang Bluetooth needs," said Thierry Laurent, executive vice president at Philips Semiconductors. "We believe high-quality stereo headsets for music and games will catch on fairly quickly," said Bryce Johnstone, worldwide manager at Texas Instruments Inc.'s short-distance wireless business unit.

The emergence of more diversified profiles means a growing demand for diversified Bluetooth silicon solutions. "Generic products don't cut it," said Ari Rauch, general manager of TI's short-distance wireless business unit. "Bluetooth is going to be commoditized."

Can we talk?

While defining the mission of the AV working group as the development of "a low-cost, low-power, globally available wireless AV standard for consumer electronics," Philips' van Bokhorst noted that one of the group's biggest challenges was to come up with a mechanism "to provide interoperability within defined application profiles."

Linking consumer electronics devices and having them directly talk to each other is no trivial task, because such systems tend to use incompatible audio codecs and do not necessarily feature vast CPU power. "We needed to consider requirements for both high-quality AV codecs and interoperability in our design decisions," said van Bokhorst. The audio world in particular is loaded with incompatible codecs ranging from MP3, AAC, and MPEG-2 audio to Dolby Digital and Atrac.

Rather than picking one winner, the AV working group has adopted a neutral technology - sub-band codec (SBC), originally developed by Philips - as a common language among consumer devices. "We chose SBC because of its low-level complexity, requiring less processing power, and because of its relatively good performance," said van Bokhorst.

The group decided that every Bluetooth-enabled consumer product compliant with the Advanced Audio Distribution Profile should incorporate, at minimum, SBC as a baseline codec to ensure the interoperability of, say, one company's Bluetooth hi-fi audio headset with another vendor's Bluetooth-enabled portable CD player. But for consumer electronics companies that wish to offer proprietary codecs in portable devices, the AV working group developed an optional codec that makes it possible to add a particular codec on top of SBC. As a result, the AV working group members had to produce a host of options detailing how "if you are using MP3 as a preferred codec, then do it this way," explained van Bokhorst. The arduous process of defining various implementations of different codecs to maintain interoperability "has been, to say the least, an interesting exercise," he added.

The AV working group similarly needs to decide on a common language for video distribution in order to maintain interoperability. Van Bokhorst said that H.263 is the video codec most likely to be used. Many companies hoped to use MPEG-4 video, he said, but MPEG-4's uncertain intellectual-property issues have discouraged that choice.

By taking advantage of its intimate knowledge of SBC, Philips Semiconductors is vying to become the first to integrate SBC encoding/decoding features onto its own Bluetooth silicon solution. SBC calls for estimated processing power of around 5 Mips.

Initially, Philips Semiconductors will offer customers "a two-processor architecture-based solution" - one for Bluetooth baseband processing and another for SBC encode/decode, said Bernhard Bauer, the company's director of marketing and sales, Europe. The first Bluetooth-enabled stereo headset prototypes will appear at the CeBIT trade show early next year, he said.

Meanwhile, in time for the volume launch of such audio headsets, Philips Semiconductors is developing a new version of its Bluetooth silicon, fully embedded with an SBC encode/decode block, Bauer added.