Patent attributes
A monitoring method for monitoring a video/audio signal transmitted from a transmission source to a transmission destination has a step of storing the video/audio signal transmitted from the transmission source to the transmission destination repeatedly for a predetermined time period, a step of comparing a first characteristic amount extracted from the video/audio signal before the transmission and a second characteristic amount extracted from the video/audio signal after the transmission in real time, a step of determining an error occurrence when there is a difference of a predetermined value or more between the first characteristic amount and the second characteristic amount, and a step of transmitting the stored video/audio signal to a predetermined destination when an error occurrence is determined.