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Chapter 2 — Overview and Operation
Any gain value requested which is outside the valid range will be limited to
+12dB to -84dB. When a value of 0dB is requested, the firmware will use the
bypass mode provided within the FPGA. Default power-up gain is 0dB, which
provides unity gain from Vela Encoders through the CineCast Quad Pro.
Bits 8 and 9 of the command determine the analog headroom of 18dB or 20dB.
This only effects the analog outputs and does not affect the digital/embedded
audio. Default is 18dB headroom, matching Vela audio/video encoders.
Command Bits
Bit 8
Bit 9
000C Slow Motion: This commands slows the playback rate. A three-bit field
(bits 8-10 of the command) determines playback speed.
Bits 10–8
000b
Examples of Actual Gain Parameters
Actual Gain
+12dB
+2.5dB
0.0dB
-2.5dB
-12dB
-84dB
Function Name
Primary Headroom
Secondary Headroom
Playback Speed
Normal rate (each frame is displayed once)
Gain Parameter
(Gain x 16)
0x0c0
0x028
0x000
0xfd8
0xf40
0xac0
Comments
0 = 18dB Headroom
1 = 20dB Headroom
0 = 18dB Headroom
1 = 20dB Headroom
DECODER Command (45h)
71
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