Signal strength measures how much radio energy a receiver detects from a transmitter, usually in decibels relative to a milliwatt. It indicates how well devices hear each other, but it does not measure interference, airtime contention or packet loss, which often matter more for video.
A wireless camera showing a full signal can still deliver unusable video. Strength describes the link margin; what a viewer notices is whether packets arrive on time and in order.
Reading the numbers
Values near minus 60 dBm indicate a comfortable link, while readings approaching minus 75 dBm are fragile. A few decibels of margin are worth more than a peak reading taken beside the access point.
Interference is separate
A crowded channel can drown a strong signal. Checking channel utilization and retry rates on both ends shows what a bar indicator cannot, especially in a warehouse full of metal racking.