What is EVRC (Enhanced Variable Rate Codec)?

Enhanced Variable Rate CODEC (EVRC) is a speech codec utilized in CDMA networks. It was created in 1995 to supplant the QCELP vocoder. EVRC compresses each 20 milliseconds of 8000 Hz, 16-bit sampled speech input into output frames of one of three different sizes: full rate – 171 bits, half rate – 80 bits, eighth rate – 16 bits. EVRC utilizes RCELP. EVRC transmits at channel rates compared to 9600, 4800 and 1200 bps frame rates.