There are two scenarios in which we will detect one way audio problems. If an inbound and outbound audio channel exist and:
a) The connection is established and inbound audio channel has traffic, but callstats does not receive any bytes for a certain amount of time (~5s) on the outbound audio channel. Example: Alice is in a call with Bob and can hear Bob (her inbound audio channel has traffic). However, whenever Alice tries to talk to Bob, Bob cannot hear her (Bob's inbound audio channel exists, but does not have any traffic).
b) Callstats has measured some bytes on the outbound audio channel, but afterwards no bytes are sent for some time (~5s). Example: Alice talks to Bob and Bob can hear her (her outbound audio channel has traffic). After some time, Bob stops hearing her (no further traffic is sent on her outbound audio channel).
Please note that if a "mute" event is detected, then the silent period will not be classified as one way audio.