Interlaced Video with Pixel Repetition - 3.2 English

HDMI 1.4/2.0 Transmitter Subsystem Product Guide (PG235)

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3.2 English

For some video formats with TMDS rates below 25 MHz (for example, 13.5 for 480i/NTSC) can be transmitted using a pixel-repetition scheme.

In the HDMI 1.4/2.0 TX Subsystem,

  • Enabled through GUI parameter upon IP generation (select Video over AXIS compliant NTSC/PAL Support)
  • Pixel repetition is only available for the AXI4-Stream interface
Note: Using AXI4-Stream, pixel repetition only supports RGB and YUV444 color space, but not 12-bit YUV422. Using the native interface, you can create customized pixel replication logic that supports all color spaces including 12-bit YUV422.

After it is enabled in the HDMI 1.4/2.0 TX Subsystem, you must prepare interlaced video as normal, then the HDMI 1.4/2.0 TX Subsystem replicates each pixel twice before sending the data out.

Because only NTSC/480i60 and PAL/576i50 are supported for pixel repetition, ensure that the correct XVDIC from the Video Common library is selected:

  • XVIDC_VM_1440x576_50_I => PAL/576i50
  • XVIDC_VM_1440x480_60_I => NTSC/480i60

For example, 480i60 video is 720x480 @ 30 Hertz, which is made from two fields of 720x240 @ 30 Hertz video.

You must select XVIDC_VM_1440x480_60_I in the software. Then in the hardware system, prepare two fields of 720x240 @ 30 Hertz video (AXI4-Stream Video) and send them to the HDMI 1.4/2.0 TX Subsystem. Then HDMI 1.4/2.0 TX Subsystem repeats each pixel twice. When the video is sent out by the HDMI 1.4/2.0 TX Subsystem, it is sent as two fields of 1440x240 @ 30 Hertz video.