ULDACC Ultra Low Delay Codec for 2-Way Audio Communication

About

Ultra Low Delay Audio Communication Coder (ULDACC) has algorithm delay in order of 0.67-2.67 msec, low complexity of both encoder and decoder (less than 100MIPS), CD quality at 128kbps with error robustness mechanism. It is perfect for wireless microphones, headphones and speakers, for Audio communication - VOIP, audio reinforcement for wireless devices, wireless rendering from microphone to speakers in Auditorium.

This technology is available with I2S and SPI drivers for ARM Cortex M series based audio wireless transmitter and receiver system and easily portable in the embedded system with SPI and I2S audio interface support. It can also be integrated in software solutions in form of API plugins for VOIP and audio communication software.

Features

  • Ultra low delay codec with algorithm delay of 0.67-2.67 msec.
  • Low encoder and decoder MIPS, perfect for low complexity and battery-operated handheld devices.
  • Error robustness and packet concealment technology, perfect for wireless system.
  • Bitstream synchronization mechanism for multiple encoders and decoders system for robust wireless transmission systems.
  • I2S and SPI interface-based SOC solution.
  • Efficient clock drift compensation at decoder side which arise due to different clock crystals used at encoder and decoder.

Specifications

  • Targets bit rates of 128-192 kbps for perceptually indistinguishable audio quality for high dynamic range (24 bit) monophonic audio signals.
  • Sampling rate support: 44.1 kHz or 48 kHz.
  • Frame size (MDCT half-window length): 128 samples (2.67ms mode), (64 samples 1.33ms mode) and 32 samples (0.67 ms mode).
  • Bit depth support: 16 and 24-bit audio (> 120 dB dynamic range).
  • Bit rates: 128, 144, 160, 180, 192 and 256 kbps/channel
  • Comparison MUSHRA Score (in %) of ACC-LD and ULDACC 2.67 ms mode (with Frame length of 128).
Music Genre
MUSHRA SCORE (%)
ULDACC 128kbps(2.67 ms delay mode)
AAC-LD @128kbps (delay 20+ ms)
Oldies 91 92
Pop 89 85
Classical 87 85
Rock 85 85
Vocal 93 90

Platforms

  • Windows x86 and x64 builds for integration in applications.
  • Linux x64 builds.
  • ARM Cortex M series architecture builds with I2S and SPI drivers-based system.
  • Full hardware encoder and decoder system ported on Atmel chips.

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