DesignWare ARC Audio OPUS Codec

The DesignWare® ARC® OPUS codec is designed for interactive speech and audio transmission over the internet. It is designed by the IETF Codec Working Group and incorporates technology from Skype’s SILK codec and Xiph.Org’s CELT codec.

The OPUS codec is designed to handle a wide range of interactive audio applications, including Voice over IP, video conferencing, in-game chat, and even remote live music performances. It can scale from low bitrate narrowband speech to very high quality stereo music.

The ARC OPUS codec supports ARC EMxD processors. The CELT portion of the codec is specifically optimized for ARC EMxD. SILK codec is implemented for ARC EMxD without target optimization.

Supported Cores

DesignWare ARC Audio OPUS Codec


  • Royalty free, IETF Standardized Universal Voice/Audio Codec
  • Bitrates of 6..510 kbps
  • Sampling rates from 8 kHz (narrowband) to 48 kHz (fullband)
  • Frame sizes from 2.5 ms to 60 ms
  • Supports both constant bitrate (CBR) and variable bitrate (VBR)
  • Supports speech and music
  • Supports mono and stereo
  • Dynamically adjustable bitrate, audio bandwidth, and frame size
  • Good loss robustness and packet loss concealment (PLC)
  • Wide audio bandwidth
  • Speech and audio codec modes supported
  • Robust to system latency
  • ARC EM9D processor load (48 kHz, 64kbps, mono) for encode & decode: 16.7 MHz
  • Small memory footprint: 90.3 KB (code ROM for CELT encoder and decoder)