To guarantee a stable broadcast in case of losing the access to the media storage, the media content can be cached locally using the Proxy function in the playout engine.
The media files are re-compressed according to the defined preset.
Video, audio and VANC are cached into separate files and divided into chunks. The size of the proxied chunks depends on the source file and proxy settings.
For example you use media files of 1080i25 format and “Best performance” proxy rendering preset. The compression ratio of this preset equals 4, MPEG2 codec. There are 2 bytes of information in one pixel.
In result, 1-hour video takes: (1920х1080х2) / 4 compression х 25 fps х 60 sec х 60 min = ~ 90 GB
Plus extra disk space for audio tracks and VANC. About 0.66 GB for 1-hour audio (one audio track) and 0.5 Gb for 1-hour VANC.