The number of video streams that a single Box can handle depends on the bitrate, resolution, and frame rate of the video streams connected to it. The max also depends on the activity observed in the scene itself. The maximum number of video streams increases quickly (non-linearly) as the bitrate and frame rate decrease, and each connected stream can have different video encoding settings.
|Max stream count of each model by resolution|
See "How do I know that a Box can handle more video streams" and the detailed related article on tuning Box VM to match the number of video streams.