The rate at which speech is encoded depends on the required audio quality and transmission bandwidth. Typically, speech encoding rates range from 8 kbps to 128 kbps. Lower rates can be used for voice communications such as telephony, while higher rates can be used for music and hi-fi audio transmission. Choosing the right rate requires balancing sound quality and transmission efficiency.
iLBC has a frame length of 30ms and a bit rate of 15.2kbps or 13.3kbps;