LC3 and LC3plus extend high audio quality to the entire communication ecosystem. The codec’s complexity meets the requirements of wireless communication platforms such as Bluetooth, DECT, and VoIP terminal equipment. By reducing the required bit rate by roughly 50 percent compared to legacy codecs, LC3 and LC3plus facilitate low-energy services that enable a longer battery life or the creation of smaller products. Due to the flexible codec design, applications are not limited to voice services but can be extended to high-quality music streaming as well.
LC3plus is the standardized solution to provide the quality of high-resolution music streaming services also over wireless accessories – facilitating independence from proprietary, vendor-specific technologies.
With LC3, it will become possible to enjoy EVS speech quality in VoLTE calls also via Bluetooth headsets. Moreover, it takes the music streaming experience on wireless accessories to the next level. The LC3 specification has been adopted by Bluetooth SIG and LC3 has been selected as the new codec for Bluetooth Low Energy (LE) Audio. In parallel, integration work into the legacy Hands-Free Profile has started.
LC3plus is LC3's sibling, equipped with numerous additional functionalities. While comprising all features of LC3, including high speech and audio quality, LC3plus incorporates functionalities for transmission robustness, extremely low-delay use cases and high-resolution audio transmission. To improve robustness, LC3plus contains a very high-performance packet loss concealment algorithm as well as forward error correction schemes such as channel coding or redundancy frame modes. Furthermore, the codec can operate at several low-delay modes – down to 5ms at a 2.5ms packet size, instead of the 7.5 ms frame length mode known from LC3. LC3plus also includes dedicated high-resolution audio modes, which improve the measurable audio quality to provide perceptual transparency (up to 500 kbit/s per channel).
LC3plus is the equivalent to EVS for landlines and enables super wideband quality for VoIP use cases, while the number of channels stays the same as in wideband. Redundancy frame modes permit the transmission of LC3plus payloads over congested VoIP channels, enabling stable phone calls even under these conditions.
LC3plus has been standardized by ETSI as TS 103 634 and brings super wideband speech/audio quality to DECT thanks to its adoption into the 2019 DECT standard. For wideband, the capacity doubles compared to the preceding standard. In terms of robustness, LC3plus’s channel coding, which was specifically designed for DECT channel characteristics, permits the transmission of LC3plus payloads over heavily distorted DECT channels – enabling phone calls without interruption, even if the handset is far away from the base station.
LC3plus’s dedicated high-resolution audio mode provides a high-quality transmission link of 24 bit and 96 kHz audio data, which performs excellently with regards to Signal-to-Noise Ratio (SNR) and Total Harmonic Distortion and Noise (THD+N). This makes it the ideal codec to bring high-transparency audio streaming to high-resolution wireless accessories such as headsets or loudspeakers. LC3plus is the only open-standard audio codec for high-resolution wireless headsets and high-quality gaming headsets. Fraunhofer IIS can provide support with the implementation of LC3plus in devices based on the Bluetooth A2DP profile.