Broadcast monitoring is software that watches every channel a broadcaster sends out, all day and night, and raises an alarm within seconds when something goes wrong on air. The faults it looks for include a black screen, a frozen picture, silence, sound in the wrong language, sound that is too loud, and missing subtitles. It is also called channel monitoring or broadcast quality monitoring.
Why is software needed? A large broadcaster may send out dozens of channels, each in several versions: for satellite, for cable and for streaming. No team of people can watch all of them closely at once. The software checks every frame of every version, and alerts a person only when something is wrong.
How does it decide what is wrong? The simplest checks use fixed limits. For example, if the brightness of the whole picture stays close to zero for more than a few seconds, the screen is probably black. If the sound level stays below a very low threshold, the channel is probably silent. Smarter systems use anomaly detection: they learn what each channel normally looks and sounds like, and flag anything unusual. A film channel may show a dark night scene that is not a fault, but a news channel almost never goes dark. Some systems check the same channel at several points: as it leaves playout, after the encoder, and as it is received from the satellite. This tells the engineers where the fault began.
Imagine a Gujarati news channel, one of 40 channels that a broadcaster's monitoring team in Mumbai looks after. At 6:14:05 pm, the channel's picture goes black. The software sees that the picture has stayed black for 3 seconds. At 6:14:08, it raises an alarm on the team's screens, and highlights that channel on the wall of screens. It also records that the picture was normal when it left playout, but black after the encoder. So the fault is in the encoder. The engineer on duty switches the channel to the backup encoder. At 6:14:40, the picture returns. The channel was black for 35 seconds, instead of many minutes. The software keeps a record of the fault, which the broadcaster may need to show to advertisers whose ads were missed.
How is this different from video quality of experience (QoE) analytics? Broadcast monitoring checks the channel that the broadcaster sends out, before it reaches viewers. QoE analytics measures what each viewer actually experiences on a phone or TV, such as how long the video took to start. The engineers' wall of screens is fed through the broadcast video router.