L64105 LSI Logic Corporation, L64105 Datasheet - Page 275

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

For a full-size PAL image, the minimum number of segments is 40. If
sufficient SDRAM memory is available, the recommended number of
segments for adequate performance is 44. The maximum number of
segments for a PAL image is 54.
Allocating more segments than the minimum will always boost decoder
performance by allowing “decode ahead” without waiting for the display
process to free up segments. Allocating extra segments is especially
recommended for applications, like letterbox display, which demand
higher decoder performance.
There are certain restrictions which must be followed when RMM is used.
SDRAM memory is dynamically allocated in this mode, and the SDRAM
memory used to reconstruct the lines of the first field are reallocated to
reconstruct other lines once the first field lines have been displayed. 3:2
pulldowns (Repeat_first_field parameter in picture coding extension) will
be processed while in RMM. However, it should be noted that the actual
display in this case will be; First Field, Last Field, Last Field. Thus, the
Repeat First Field is actually implemented as a Freeze Last Field during
RMM while displaying B-pictures.
Another restriction is the display modes that are allowed with RMM. Only
the following modes may be used in conjunction with RMM:
For more information on display modes, see
and Vertical Filtering.”
Frame Store Modes
Min NumSegments
Total Lines
---------------------------- - 1
Display Mode 4: Interlaced Chroma Field Repeat and No Filter
Display Mode 5: Interlaced Chroma Field Repeat and Filter
Display Mode 6: Interlaced Chroma Line Repeat
Display Mode 7: Interlaced Chroma Line Repeat and Filter
Display Mode 8: Interlaced 0.75 Letterbox Filter
Display Mode 10: Interlaced Repositioning
Display Mode 11: Interlaced 0.5 Letterbox Filter
8
–
Max Num Segments 54
=
Total Lines
---------------------------- -
8
+
4
Section 9.6, “Display Modes
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