DigitalVideoAndHDTVAlgorithmsAndInterfaces.pdf

Word Value MSB 9 8 7 6 5 4 3 2 1 LSB 0
0 3FF h 1 1 1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0 0 0 0
4 ID PAR PAR X 4 X 3 X 2 X 1 X 0 FR 1 FR 0 F
Table 33.4 TRS-ID in 4f SC comprises five words. Line number is coded in word 4, in 5 bits X 4
through X 0; these bits count from 1 to 31 in each field, then saturate at 31. Bits FR 1 and FR 1 identify
colorframes; bit F is asserted for the second field.
Ideally, these are lines 313 and
625; see page 533.
TRS-ID in 4f SC composite video
I introduced the Composite digital SDTV (4f SC ) interface,
on page 129. In composite 4f SC , active video is
digitized and transmitted across the interface with one
word for each sample clock. Sync edges and the back
porch (including burst) are included among the
samples.
In composite 4f SC NTSC, sampling is at [I, Q] phase, as
I will detail in Chapter 42, on page 511. No sample
precisely coincides with 0 H in the analog domain.
In composite 4f SC PAL, sampling is at [U+V, U-V] phase,
as I will detail in Chapter 44, on page 529. Owing to
4f SC PAL not being line-locked, the position of 0 H
changes line-by-line. The relationship between sync and
subcarrier in PAL causes a further complexity: Each line
has 1135 samples, except for two lines per frame which
contain 1137 samples each.
In 4f SC , the synchronization sequence is called TRS-ID;
it is located in the analog synctip interval, commencing
several samples after 0 H. TRS-ID structure is shown in
Table 33.4 above. The SAV and EAV codes of Rec. 601
are not used. The first four words, denoted TRS, contain
the fixed sequence {3FF h, 0, 0, 0}. The final word,
denoted ID, conveys line number and field/frame data.
Line number is coded in 5 bits, X 4 through X 0; the
count runs from 1 to 31, then saturates at 31.
CHAPTER 33 DIGITAL SYNC, TRS, ANCILLARY DATA, AND INTERFACE 393