
Philips Semiconductors
PNX15xx Series
Volume 1 of 1
Chapter 21: MPEG-1 and MPEG-2 Variable Length Decoder
PNX15XX_SER_3
Koninklijke Philips Electronics N.V. 2006. All rights reserved.
Product data sheet
Rev. 3 — 17 March 2006
21-17
31:28
Vertical back. rsize
R/W
NI
Number of bits per backward vertical motion vector that are residual
in the picture.
27:24
Horizontal back. rsize
R/W
NI
Number of bits per backward horizontal motion vector that are
residual in the picture.
23:20
Vertical for. rsize
R/W
NI
Number of bits per forward vertical motion vector that are residual in
the picture.
19:16
Horizontal for. rsize
R/W
NI
Number of bits per forward horizontal motion vector that are residual
in the picture.
15:14
Reserved
R
13
mpeg2mode
R/W
NI
1 = indicates if the current sequence is MPEG-2
0 = indicates if the current sequence is MPEG-1 (for error checking
only)
12:7
Reserved
R
6
mv_concealment
R/W
NI
1 = indicates forward motion vectors are coded in all intra
macroblock headers of a picture.
0 = indicates forward motion vectors are not coded in all intra
macroblock headers of a picture.
5
R/W
NI
Use DCT table zero (intra_vlc = “0”)or one (intra_vlc = “1”)
4
frame_prediction_frame
_dct
R/W
NI
If 1, motion_type = FRAME, and dct_type = 0.
If 0, motion_type and dct_type follow the decoded values in the
mb_header from the VLD. CPU should set it to 0 for Field Pictures
and 1 for MPEG-1.
3:2
picture_structure
R/W
NI
1=top-eld
2=bottom-eld
3=frame picture
0=reserved.
1:0
picture_type
R/W
NI
1=I
2=P
3=B
0=D (MPEG-1 only)
Offset 0x07 5010
VLD_MC_STATUS
31:16
Reserved
R
15:7
Reserved
R/W
6
RL overow
R/W
0
Logic ‘1’ indicates Overow of run/level values with in a block. Refer
procedure. This bit is cleared by writing a logic ‘1’ to it.
5
DMA RL output done
R/W
0
Logic ‘1’ indicates that the Run Length data FIFO has been written
to main memory. This bit is cleared by writing a logic ‘1’ to it.
4
DMA Header output
done
R/W
0
Logic ‘1’ indicates that the Run Length data FIFO has been written
to main memory. This bit is cleared by writing a logic ‘1’ to it.
3
DMA input done
R/W
0
Conditions for setting this bit depends on the value of the
DMA_Input_Done eld in the VLD_CTL register. Refer to
Table 3This bit is cleared by writing a logic ‘1’ to it.
Table 10: VLD Registers …Continued
Bit
Symbol
Acces
s
Value
Description