X 720p 74.250 MHz 24.000 Hz 25 or 29.97 Hz (30/1.001) to simplify the generation 1280 X 720p 74.250 MHz 25.000 Hz of (B, D, G, H, I) PAL or (M) NTSC video. The analog interface uses 1125 lines per frame, with active video 1280 X 720p 74.176 MHz 29.970 Hz present on lines 21-560 and 584-1123, as shown in X 720p 74.250 MHz 30.000 Hz Figure 7.3-30. MPEG-2 and MPEG-4 systems use 1088 lines, rather X 720p 74.250 MHz 50.000 Hz than 1080, in order to have a multiple of 32 scan lines per 1280 X 720p 74.176 MHz 59.940 Hz frame. In this case, an additional 4 lines per field after the active video are used. 1280 X 720p 74.250 MHz 60.000 Hz For the 25 Hz frame rate, each scan line time is about 35.56 us. For the 29.97 Hz frame rate, each scan line Note that square pixels and a 16:9 aspect ratio are used. time is about 29.66 us. Detailed horizontal timing is Example relationships between the analog and digital dependent on the specific video interface used. signals are shown in Figures 7.3-27 and 7.3-28, and Table 7.3-1. The H (horizontal blanking), V (vertical blanking), 1152i Format and F (field) signals are as defined in Figure 7.3-29. The 1152i active (1250 total) line format is not a broad- cast transmission format. However, it is being used as an 1080i and 1080p Systems analog interconnection standard from HD set-top boxes and DVD players to 50 Hz CRT-based HDTVs. This Interlaced analog component video enables 50 Hz HDTVs to use a fixed 31.25 kHz hori- zontal frequency, reducing their cost. Other HDTV Analog component signals are comprised of three sig- display technologies, such as DLP, LCD, and plasma, nals, analog R'G'B' or YPbPr. Referred to as 1080i are capable of handling the native timing of 720p50 START VSYNC Figure 7.3-26 720p Vertical Interval Timing. CHAPTER 7.3 Video signals overview SAMPLE RATE = 74.176 OR 74.25 MHZ [C] SAMPLES 110 SAMPLES DIGITAL BLANKING DIGITAL ACTIVE LINE DIGITAL [B] SAMPLES 1280 SAMPLES BLANKING DIGITAL ACTIVE LINE 370 SAMPLES 1280 SAMPLES TOTAL LINE (0-369) (370-1649) [A] SAMPLES TOTA