L64105 LSI Logic Corporation, L64105 Datasheet - Page 316

• Manufacturer Part Number: L64105
• Description: Mpeg-2 Audio/video Decoder
• Manufacturer: LSI Logic Corporation

9.9.1 OSD Modes
9.9.2 Internal OSD
9.9.2.1 OSD Display Area Storage Layout
9-24
The OSD controller supports three basic image formats:
The host can select the OSD mode by setting the OSD Mode bits in
Register 265
Table 9.7
The internal OSD modes use the on-chip color palette and the OSD
Controller. The external OSD mode simply uses the on-chip color palette
and a color look-up value supplied on the L64105 EXT_OSD pins.
For internal OSD mode, the host must write a header containing control
information and an optional color palette, and an image bitmap to
SDRAM for each OSD display area. This is best done using an external
DMA Controller.
Figure 9.13
area using 4 bits/pixel resolution. There are four words of control
information followed by a 16-word palette. The palette is followed by the
bitmap image. For 2 bits/pixel resolution, only a 4-color palette is
required. For 8 bits/pixel resolution, a 256-color palette is required. The
pixel data (2, 4, or 8 bits/pixel) is packed with pixel 0 (D0) in the upper
bits of the first word of the bitmap. This layout is repeated for each OSD
display area.
Video Interface
OSD Mode Bits Description
Up to 720 x 576 pixels at 2 bits/pixel
Up to 720 x 576 pixels at 4 bits/pixel
Up to 720 x 576 pixels at 8 bits/pixel
0b00
0b01
0b10
0b11
illustrates the SDRAM word organization of an OSD display
OSD Modes
(page
No OSD (default)
Internal OSD (Contiguous)
Internal OSD (Linked List)
External OSD
4-58).
Table 9.7
shows the coding of the bits.