G.722.1 ITU-T compatible vocoder

ITU G.722.1 is digital wideband coder algorithm that provides an audio bandwidth of 50 Hz to 7 kHz, operating at a bit rate of 24 kbit/s or 32 kbit/s. The sampling frequency for this algorithm is 16 KHz. The algorithm is based on transform technology, using a Modulated Lapped Transform (MLT). It operates on 20 ms frames (320 samples) of audio. Because the transform window (basis function length) is 640 samples and a 50 per cent (320 samples) overlap is used between frames, the effective look-ahead buffer size is 20 ms. Hence the total algorithmic delay of 40 ms is the sum of the frame size plus look-ahead. All other delays are due to computational and network transmission delays.


SoftRISC supports several processor platforms and maintains optimization efforts to improve performance specifications.