
Multimedia Registers
16-17
`efmp69030 Databook
Revision 1.3 11/24/99
MR20/A0
Playback Control 3 Register
read/write at I/O address 3D3h with index at address 3D2h set to 20h/A0h
shared & shadowed for each playback engine at MR20, and cross-shared for the other at MRA0
7
Playback Vertical Auto-Centering Enable
0: Allow software to employ a delay to properly center the playback window vertically. This
is done usually via bit 4 of the Pixel Pipeline Configuration Register 1 (XR81).
1: Activate a hardware-based auto-centering mechanism.
6
Playback Width Source
0: Uses MR28 for Playback width
1: Uses MR34 for Playback width
5
Playback Pointer Select 1
0: The pointer to the location in the frame buffer from which frames/fields of video data are
played back is selected by bit 4 of this register.
1: The pointer to the location in the frame buffer from which frames/fields of video data are
played back is controlled by bit 3 of this register.
4
CPU Double Buffer Flag
0: Playback memory address PTR1
1: Playback memory address PTR2
3
Playback Pointer Select 2
0: The pointer to the location in the frame buffer from which frames/fields of video data are
played back is selected by bit 4 of this register.
1: The pointer to the location in the frame buffer from which frames/fields of video data are
played back toggles between the addresses indicated by PTR1 and PTR2 after each frame/
field captured.
2
Double Buffer Trigger
0: Retains old PTR.
1: Takes new PTR on next VSYNC if bit 5 is set to 1.
1-0
Reserved
76543
210
PB
1
Playback
Vert. Autoctr
Enable
Playback
Width
Source
Playback
Pointer
Select
CPU Double
Buffer Flag
Playback
Pointer
Select 2
Double
Buffer
Trigger
Reserved
PB
2
Playback
Vert. Autoctr
Enable
Playback
Width
Source
Playback
Pointer
Select
CPU Double
Buffer Flag
Playback
Pointer
Select 2
Double
Buffer
Trigger
Reserved
Bit
5 4 3
Playback Pointer Select
0 0 X
Selects playback memory pointer address 1
0 1 X
Selects playback memory pointer address 2
1 0 0
Selects playback memory pointer address 1
1 0 1
Pointer to the location from which frames/fields of data are read toggles between
addresses indicated by PTR1and PTR2 after each frame/field captured
1 1 0
Selects playback memory pointer address 2
1 1 1
Pointer to the location from which frames/fields of data are read toggles between
addresses indicated by PTR1and PTR2 after each frame/field captured