6-22
Video Interface and On-Screen Display
Final Rev F
Copyright 1996 by LSI Logic Corporation. All rights reserved.
Figure 6.11
Freeze Frame for One
Field Time
If freeze frame is implemented on every other frame of a sequence which
has 24 frames per second instead of the NTSC standard of 30 frames
per second, the effect of 3:2 Pull Down can be achieved.
Note that the eld parity is maintained whenever freeze frame is issued;
that is, the TOP eld is always an Odd eld and the BOTTOM eld is
always an Even eld. Also note that by freezing a frame for only one eld
time, the next frame starts with the BOTTOM eld rst rather than the
usual order of TOP eld rst. In the example shown in
Figure 6.11, frame
B3 starts with the BOTTOM eld rst.
6.7.1.3 Slow Motion
The DSM sends pictures at a slower rate with an indication of how many
times each eld is repeated to accomplish slow motion. The L64005 per-
forms slow motion under control of the host controller. The host controller
asserts the Decode Start signal at the appropriate time for the Presen-
tation Unit (PU). The L64005 waits until the next PU boundary (frame or
eld sync, depending on coding mode) then begins to decode the pic-
ture. The host controller then immediately signals freeze eld for the rst
Decode
Sequence
e0
e1
e2
e3
e4
e5
e6
e7
e8
e9
e10
e11
e12
o1
o2
o3
o4
o5
o6
o7
o8
o9
o10
o11
o12
I0 I0 P1 P1 B2 B2
B3 B3
I0 I0 B2 B2 B2 B3 B3
BTBTBTBTBT
Display
Sequence
Field Parity
Decode
Start/Stop bit
Freeze
Frame bit
Notes:
1. This is an example of freezing a frame for one eld time. Here frame ‘B2’ is displayed in o3 and e3 eld times
and the top eld of ‘B2’ is frozen in o4 eld time.
2. This technique may be used to achieve 3:2 pull down using the host instead of from the bitstream.
MD96.229