Texas Instruments TMS320C64x DSP - Manual (Page 92)

Video Input Filtering
Video Capture Port 3-30 SPRU629
Figure 3–16 shows an example of a capture window that is smaller than the
BT.656 active line. Sample a is the first sample in the horizontal capture
window and sample n is the last sample. In this case, any filtering done on the
first sample location uses the m leading edge captured pixels (m is 3 in this
example), and any filtering done on the last sample location uses the m trailing
captured pixels. (From an implementation standpoint, the mirroring and filter-
ing can still begin and end with SAV and EAV, but the samples before
VCXSTART or after VCXSTOP must not be saved to the YCbCr buffers.)
Figure 3–16. Capture Window Not Requiring Edge Pixel Replication
a
Luma (Y)
sample
–
Chroma (Cb/Cr)
samples
–
b c d e a–4 a–3 a–1 n–1 n n+1 n+2 n+3 n–4 n–3 n–2
a–2 a–1 a b c SAV n–1 n EAV n–4 n–3 n–2
Leading edge replicated pixels
Trailing edge replicated pixels
Active line
a–4 a–3 d e n+4 n+1 n+2 n+3
XSIZE
XSTART