AR# 66435

LogiCORE IP Video Processing Subsystem v1.0 - Clarification of color space mappings

Description

The product guide for the Video Processing Subsystem (PG231 from November 18, 2015) is not clear on some of the color mappings.

Particularly, Tables 2-5, 2-6, and 2-7.

Solution

Regarding Table 2-5 (Dual Pixels per Clock, 10 Bits per Component Mappint for YUV 4:2:2), 4:2:2 has 2 channels.

One channel carries Y and the second channel carries U and V interleaved in time, starting with U every line.

So when you do this for 2 pixels per clock, the mapping is as follows:

59:50 49:40 39:30 29:20 19:10 9:0
Zero padding
Zero padding V0 Y1 U0 Y0

4:2:0 adds vertical subsampling to 4:2:2 which is implemented in the AXI4 Stream by simply omitting the Chroma data on every other line. 

For example, for the first line in the frame (i.e. line 0 which is even) is mapped:


59:50 49:40 39:30 29:20 19:10 9:0
Zero padding
Zero padding V0 Y1 U0 Y0

Now, because the odd lines do not contain a valid Chroma component, they look like this:


59:50 49:40 39:30 29:20 19:10 9:0
Zero padding
Zero padding XXXX Y1 XXXX Y0

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AR# 66435
Date 01/21/2016
Status Archive
Type General Article
IP