containerBitrate

What the container declares as its overall bit rate, in bits per second.

The container's own claim, and deliberately not the same number as the measured throughput beside it: on variable-bit-rate media the two differ, and which one a reader wants depends on whether they are asking what the file says or what actually flowed.

Null when the container declares none, which is normal for a live stream, and for a source that does not report it.