Slave devices pass through the tally packet on their output and update the monitor tally
status
so that monitor devices connected to that individual output may display tally status
,
without knowledge of the device id they are monitoring
Assumptions
Any data alignment
/
padding is explicit in the protocol
Blanking
Encoding
One tally control packet may be sent per video frame
291M packet with DID
/
packet may contain up to 256 bytes of tally information
Packet
Format
Each tally status consists of 4 bits of information
uint4
bit 0
:
bit 1
:
bit 2
-
3
:
The first byte of the tally packet contains the monitor device tally status and a version number
Subsequent bytes of the tally packet contain tally status for pairs of slave devices
master device sends tally status for the number of devices configured
maximum of 510
.
struct tally
uint8
:
bit 0
bit 1
:
bit 2
-
3
:
bit 4
-
7
:
[
]
uint8
0
bit 0
:
bit 1
:
bit 2
-
3
:
:
bit 4
bit 5
:
bit 6
-
7
:
uint8
[
1
]
:
bit 0
bit 1
:
bit 2
-
3
:
bit 4
:
:
bit 5
bit 6
-
7
:
. . .
SDID x51
x52 in the active region of VANC line 15
/
program tally status
(
0
=
off
preview tally status
(
0
=
off
reserved
(
0x0
)
monitor device program tally status
monitor device preview tally status
reserved
(
0b00
)
protocol version
(
0b0000
slave device 1 program tally status
slave device 1 device preview tally status
reserved
(
0b00
)
slave device 2 program tally status
slave device 2 preview tally status
reserved
(
0b00
)
slave device 3 program tally status
slave device 3 device preview tally status
reserved
(
0b00
)
slave device 4 program tally status
slave device 4 preview tally status
reserved
(
0b00
)
.
.
Bit fields are packed from LSB first
.
Packets are encoded as a SMPTE
.
:
,
1
=
on
)
,
1
=
on
)
/
(
=
,
=
)
0
off
1
on
(
0
=
off
,
1
=
on
)
)
(
0
=
off
,
1
=
on
)
(
0
=
off
,
1
=
on
(
=
,
=
)
0
off
1
on
(
0
=
off
,
1
=
on
)
(
=
,
=
)
0
off
1
on
(
0
=
off
,
1
=
(
0
=
off
,
1
=
on
)
(
=
,
=
)
0
off
1
on
DeveloperInformation
.
A tally control
.
.
.
The
supported
,
up to a
)
on
)
1732