When discussing VoIP, what does look-ahead mean?
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What is look-ahead used for in Voice over IP (VoIP)? Regarding voice codecs, look-ahead is used to detect patterns in voice transmission to save on bit rate capacity. Look-ahead delay is used by a coder's algorithm to aid in voice compression. Look-ahead is a period of time when the coder looks at packet N+1 for patterns on which it can compress while coding Packet N. With G.711, the look-ahead is 0.
For more information:
- Read up on our voice and video codec primer.
- Understand how voice compression saves bandwidth.
- Learn how to analyze voice traffic with a Wireshark packet capture.
This was first published in October 2013