TM1100 Preliminary Data Book
Philips Semiconductors
14-4
PRELIMINARY INFORMATION
File: vld.fm5, modified 7/26/99
14.5.2
Run-Level Output Data
The DCT coefficients associated with the macroblock are
output to a separate memory area and each DCT coeffi-
cient is represented as one 32-bit quantity (16 bits of run
and 16 bits of level). For intra blocks, the DC term is ex-
pressed as 16 bits of DC size and a 16-bit value whose
most significant bits (the number of bits used for DC level
is determined by DC size) represent the DC level. Each
block of DCT coefficients is terminated by a run value of
0xff.
14.6
VLD TIME SHARING
The TM1100 VLD is targeted for a single bitstream de-
code and there is no provision to decode more than one
bitstream by using the VLD in time multiplexed mode.
However internal development has shown that up to 4 si-
multaneous MPEG1 bitstreams can be decoded. Proce-
dure is out of the topic of this data-book and can be
asked through the customer support.
14.7
MMIO REGISTERS
To ensure compatibility with future devices, any unde-
fined MMIO bits should be ignored when read, and writ-
ten as zeroes.
14.7.1
VLD Status (VLD_STATUS)
This register contains current status information which is
most pertinent to the normal operation of an MPEG video
decode application. VLD status description is detailed in
ter hardware reset) is 0.
Interrupts can be enabled for any of the defined status
bits (see following VLD_IMASK description). Acknowl-
edgment of the interrupt is done by writing a one to the
corresponding bit in VLD_STATUS register. Writing a
one to the bits one through five clears the corresponding
bits. However bit 0 (COMMAND_DONE) is cleared only
by issuing a new command. Writing a one to bit 0 of the
status register will result in undefined behavior of the
VLD. Note that several status bits may be asserted si-
multaneously. Thus it is recommended to use level trig-
carefully acknowledge the interrupt.
14.7.2
VLD Interrupt Enable (VLD_IMASK)
This register allows the DSPCPU to control the initiation
of the interrupt for the corresponding bits in the VLD Sta-
tus Register. Writing a one into any of the defined
VLD_IMASK bits enables the interrupt for the corre-
sponding bit in the status register (VLD_STATUS). De-
fault value (after hardware reset) is 0.
Esc Count
MBA Inc
MB Type
Motion Code [0][0][1]
Motion Residual [0][0][0]
Motion Residual [0][0][1]
Motion Code [0][0][0]
Motion Code [0][1][1]
Motion Residual [0][1][0]
Motion Residual [0][1][1]
Motion Code [0][1][0]
quant scale
CBP
31
First Forward Motion Vector
First Backward Motion Vector
0
1
2
3
4
6
11
17
25
7
15
23
29
30
31
13
7
15
23
29
30
31
13
4
10
12
14
31
Figure 14-3. MPEG1 Macroblock Header Output Format
w1
w2
w3
w0
MB1
MB2