Uninformed: Informative Information for the Uninformed

Vol 8» 2007.Sep

RTP Payload Redundant Bits

RTP packet payloads are essentially encoded multimedia data. RTP payloads may contain any type of multimedia data. However, this research effort focused entirely on audio. Specifically, audio encoded with the G.711[17] Codec. Any number of audio Codecs can be used to encode the RTP payload, the identifier of which is included in the RTP packet's header as the payload type (PT) field.

The frequency, locations, and number of redundant bits found within the RTP packet's encoded payload are determined by the Codec that is used to encode the audio transmitted by an individual packet. The Codec focused on during this research, G.711, uses a 1-byte sample encoding and is generally resilient to modifications to the least significant bit[18] (LSB) of each sample. Codecs with larger samples may provide for one or more bits per sample to be modified without any discernible audible change in the encoded audio, which is defined as the audio's audible integrity.