Technical Specifications
KLV Data Specifications
Makito
X User’s Guide, v2.2, Issue 02
392
KLV Data Specifications
NOTE
In case the KLV serial data is transmitted from the source to the Makito
X
over
a relatively error-prone medium (such as wireless), it is up to the System Integrator to
insure the integrity of the KLV packets by using data recovery mechanisms such as
Forward Error Correction, etc.
Even with the recovery mechanisms provided by the System Integrator, there will still be
some corrupted KLV data messages (e.g., the 5-byte key preamble is corrupted). The
Makito
X will use serial data inactivity periods of 500ms to re-initialize the internal KLV
packet framer. This is in order to minimize error propagation.
Again to minimize the chance for the Makito
X to not recover from potentially corrupted
KLV data, the length of a KLV packet shall not exceed 500ms. Beyond this time limit, the
Makito
X will consider that the incoming serial data was probably corrupted (it was not
able to find the KLV packet boundaries) and will therefore look for the next 5-byte
preamble.
KLV Input
The serial KLV data is compliant to SMPTE 336M-2007.
A 16-byte Universal Key is used to separate successive
KLV packets (messages).
The first 5-byte preamble (06 0E 2B 34 02) is used by the
Makito
X to sync on the beginning of a new KLV packet.
The incoming serial KLV data is also formatted as per
SMPTE 336M-2007 Local Data Set Coding.
Examples of KLV group coding are described in MISB
0601.5, Section 5 UAS Datalink Local Data Set. (See
below for additional implementation considerations).
Stream Insertion
Compressed video frames (and associated KLV data) are
time-stamped as per MISB 0604 Section 5.3. It is assumed
that users will pre-configure the Makito
X Internal System
Clock to the desired UTC time.
The KLV metadata is inserted in the MPEG stream as per
MISB 0604, Section 7.2 – Synchronous Carriage of
Metadata.
References
SMPTE 336M-2007 Data Encoding Protocol using Key-
Length-Value
MISB 0601.5 UAS Datalink Local Metadata Set
MISB 0604 Time Stamping Compressed Motion Imagery