Interlaced Video - 1.2 English

HDMI 2.1 Transmitter Subsystem Product Guide (PG350)

Document ID
PG350
Release Date
2022-04-27
Version
1.2 English

The HDMI 2.1 TX Subsystem is designed to support both progressive and interlaced video. In this section, the focus is to show how to handle interlaced video as it is more straightforward for progressive video.

Taking 1920x1080@50 Hz (I) as an example, the detailed timing information is shown in the following table.

Table 1. Timing Data
Name Timing Field Subset Value
HActive   1920
HBlank   720
  HFrontPorch 528
  HSyncWidth 44
  HBackPorch 148
HTotal   2640
VActive   540
F0VBlank   22
  F0PVFrontPorch 2
  F0PVSyncWidth 5
  F0PVBackPorch 15
F0PVTotal   562
F1VBlank   23
  F1VFrontPorch 3
  F1VSyncWidth 5
  F1VBackPorch 15
F1VTotal   563

For interlaced video, each frame consists of two fields. One field carries the odd lines and the other field carries the even lines. After putting both fields together, you get the complete frame. Therefore,

  • Vertical Active per Field = Vertical Active Lines / 2
  • Frame Rate = Field Rate / 2.

In this example,

  • VActive = 1080/2 = 540
  • Field Rate = 50 Hz
  • Frame Rate = 50/2 = 25 Hz

To design using the AXI4-Stream Interface, generate two fields of video with timing using the values from the previous table. For complete timing information, refer to CTA-861-H. Only active video data compliant with AXI4-Stream protocol is needed. The AXI4-Stream to Video Out core inside the HDMI 2.1 TX Subsystem converts the AXI4-Stream video into native video. Ensure that fid is driven to align with the field video data. For details, refer to the AXI4-Stream to Video Out LogiCORE IP Product Guide (PG044).