4-54
Register Descriptions
Current Decode Frame [1:0]
R [5:4]
These bits indicate which frame store is being used for
reconstruction as shown in the following table.
Reserved
[7:6]
Clear these bits when writing to this register.
Figure 4.79
Register 239 (0x0EF)
Reserved
0
Clear this bit when writing to this register.
Host Force Broken Link Mode
Setting this bit disables the display of certain B pictures
in a Group of Pictures (GOP) by forcing the Broken Link
bit to 1. If the bitstream indicates an open GOP and this
bit is set, then any B pictures before the first I picture in
the GOP are skipped. The Video Interface, however,
stays synchronized with the display since only one B
picture is skipped per frame display period. This is
different from merely skipping B pictures which skips
each B picture as fast as possible and does not control
the rate of the skip with respect to the display.
R/W 1
Panic Prediction Enable
R/W 2
Setting this bit causes the motion compensation module
to go into a panic mode. In this mode, the motion
compensation module performs motion compensation
using only the forward vector set and ignores the
backward vectors for B pictures. Similarly for dual-prime
motion vectors, only same parity prediction is performed.
This mode is intended to be used in situations where
limited SDRAM bandwidth slows down picture
Current Display
Frame
Description
0b00
0b01
0b10
0b11
Anchor 1
Anchor 2
B
Reserved
7
6
5
4
3
2
1
0
Reserved
Ignore
Sequence
End
Force Rate
Control
Concealment
Copy Option
GOP User
Data Only
Panic
Prediction
Enable
Host Force
Broken Link
Mode
Reserved