Optimally using the Bluetooth subband codec

The Bluetooth Special Interest Group (SIG) has standardized the subband coding (SBC) audio codec to connect headphones via wireless Bluetooth links with the A2DP profile. SBC compresses audio at high fidelity while having an ultra-low algorithm delay and very low complexity. SBC is configurable to a very large extend. Six parameters can be changed including sampling frequency, bit rate and algorithmic delay. In total, more than 60000 different configuration can be selected. In this publication, we objectively measure the audio and speech quality, if SBC runs under those configurations to find the most suitable parameter under given rate and delay constrains. Finally, we present objective tests comparing the audio codecs SBC, CELT, APT-X and ULD.