Developer Information; Blackmagic Sdi Camera Control Protocol - Blackmagic Design Studio Camera 4K Plus Manual De Instalación Y Funcionamiento

Developer Information

Blackmagic SDI Camera Control Protocol

Version 1.5
If you are a software developer you can use the Blackmagic SDI to construct devices that integrate
with our products. Here at Blackmagic Design, our approach is to open up our protocols and we
eagerly look forward to seeing what you come up with!
Overview
This document describes an extensible protocol for sending a unidirectional stream of small control
messages embedded in the non-active picture region of a digital video stream. The video stream
containing the protocol stream may be broadcast to a number of devices. Device addressing is used
to allow the sender to specify which device each message is directed to.
Assumptions
Alignment and padding constraints are explicitly described in the protocol document. Bit fields are
packed from LSB first. Message groups, individual messages and command headers are defined as,
and can be assumed to be, 32 bit aligned.
Blanking Encoding
A message group is encoded into a SMPTE 291M packet with DID/SDID x51/x53 in the active region
of VANC line 16.
Message Grouping
Up to 32 messages may be concatenated and transmitted in one blanking packet up to a maximum
of 255 bytes payload. Under most circumstances, this should allow all messages to be sent with a
maximum of one frame latency.
If the transmitting device queues more bytes of message packets than can be sent in a single frame,
it should use heuristics to determine which packets to prioritize and send immediately. Lower priority
messages can be delayed to later frames, or dropped entirely as appropriate.
Developer Information
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