streamName — i-PRO official camera and recorder MIBs
"Stream1", "Stream2", …"Stream4"
Official device manual: SNMP MIB manual for i-PRO camera — version 2.0 (current catalog) — PDF page 31.
Qualified manual context: PDF page 31 prints storageName at .1.3.6.1.4.1.57501.100.1.12.3.1.2. The retained native MIB independently declares streamName at 1.3.6.1.4.1.57501.100.1.12.3.1.2. This explanatory text is attached to that native declaration; the contradictory manual fields are retained, not substituted for the native assignment or type. Confirm behaviour on the relevant device edition.