Bt.656 Image Window And Capture - Texas Instruments TMS320C64x DSP Reference Manual

BT.656 Video Capture Mode
Table 3–4. Error Correction by Protection Bits (Continued)
Received Received
000
P P –P –P Bits Bits
3 3 0 0
0111 100
1000 000
1001 –
1010 –
1011 010
1100 –
1101 001
1110 –
1111 –
3.2.3

BT.656 Image Window and Capture

The BT.656 format is an interlaced format consisting of two fields. The video
port allows capture of one or both fields. The captured image is a subset of
each field and can be larger or smaller than the active video region. The cap-
tured image position is defined by the VCxSTRT1 and VCxSTOP1 registers
for field 1, and the VCxSTRT2 and VCxSTOP2 registers for field 2. The
VCXSTART and VCXSTOP bits set the horizontal window position for the field
relative to the HCOUNT pixel counter. The VCYSTART and VCYSTOP bits set
the vertical position relative to the VCOUNT line counter. This is shown in
Figure 3–1.
HCOUNT increments on every chroma sample period (every other VCLKIN
rising edge) for which capture is enabled. Once VCOUNT = VCYSTART, line capture
begins when HCOUNT = VCXSTART. It continues until HCOUNT = VCXSTOP. A
field's
VCOUNT = VCYSTOP.
3-6 Video Capture Port
Received F, V, and H Bits
001 010 011
– – 011
– – –
001 010 –
101 010 –
– 010 010
001 110 –
001 – 001
– – 011
001 010 –
capture is complete
100 101 110
100 100 100
– 101 110
– – –
101 101 –
– 101 010
110 – 110
– 001 110
– 101 110
100 – –
when HCOUNT = VCXSTOP
111
–
–
111
101
–
110
–
–
–
and
SPRU629