Robust DTMF detection in an unreliable voice-over-IP (VoIP) environment

摘要

A method to discriminate a signal as a DTMF digit is operative in a service provider having a VoIP-based media server. The media server accepts both in-band DTMF and RTP telephone events. A digit detection module receives as input a data stream that may include one or more DTMF digits. The module processes the input data stream and provides, as output, an indication of what digit(s) have been detected and from what source (e.g., in-band audio, an RTP 2833 telephone event, of both). The output is then further processed by a discrimination algorithm to make a final digit determination. If RTP telephone events are detected, the algorithm prefers them and ignores in-band DTMF until the call ends or the media is re-negotiated. The approach detects when duplicate digits of differing types are initially received and only accepts one of them, regardless of spacing or duration.

主权项

1. An article comprising a tangible, non-transitory machine-readable medium that stores a program, the program being executable by a media server machine having a hardware component, the media server machine connectable to at least one VoIP carrier, comprising:
first program code operative during an outbound call to receive a data stream from the at least one VoIP carrier; second program code to identify all in-band DTMF and RTP telephone event data in the received data stream; and third program code to filter the in-band DTMF and RTP telephone event data to determine whether the data stream includes a DTMF digit indicative of a keypad press.