CSR is claiming it is possible to simplify and speed the development of Bluetooth headsets with high quality stereo audio with a new type of software development kit.
The wide use of wireless technologies, such as Bluetooth and WiFi, allows users to receive digital audio by streaming over Wi-Fi from a Mac or PC, or by connecting a transmitter dongle to a mobile-audio device and listening with wireless headphones.
An important feature of the TrueWireless Stereo software development kit is the incorporation of audio enhancement technology for improved audio quality through a microphone and clearer audio through the earpiece through noise cancellation.
“The software development kit has already attracted interest from a number of tier one customers, and it will allow manufacturers to focus on building unique products in the rapidly growing Bluetooth stereo headset and speaker markets,” said Anthony Murray, senior v-p for the audio and connectivity strategic business unit at CSR.
Bandwidth limitations can be an issue for wireless-system applications as manufacturers strive for ultra-low power consumption in mobile devices. For live streaming, audio coding delays are again prohibitive constraints. Such delays have implications for video applications requiring lip-synching – for example, when using a wireless stereo headset with a video playback-supported iPod or a mobile TV receiver.
To address this, the Bluetooth SIG (Special Interest Group) has ratified the A2DP standard to manage the transfer of stereo audio, and the consumer market has subsequently experienced the arrival of A2DP-enabled products on both the audio source and headset sides.
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One issue has been the reluctance of some consumer audio companies to integrate the A2DP profile in products, due largely to the issues of audio quality and coding delay. The industry regards 16-bit audio as the entry-level quality requirement for audio systems now on the market, along with a minimum sample rate of 44.1kHz to match that of CD audio.
Based on the BlueCore5-Multimedia platform, the kit makes use of two Bluetooth devices, one as the master and the other as the slave. The call handling and control are supported on the master device which then relays the audio stream to the slave headset.
Audio is streamed from the audio source to the master unit and is relayed to the slave using CSR’s proprietary synchronisation protocol, resulting in wireless stereo sound to either a headset or speakers.
According to the Cambridge-based Bluetooth firm, this allows the product to work with any existing A2DP device already on the market.
TrueWireless stereo also supports Bluetooth version 2.1 + EDR along with sub-band coding or MP3 audio file formats.
CSR will be giving demonstrations of TrueWireless Stereo at CES, Las Vegas from 8-11 January.