# What does yuv420 output mean in camera?

Now I'm reading a datasheet which is ov5642.

But I can't understand the explain table6-6 format control register of yuv420.

Q1.How does yuv420 could be express such as "YYYY..../YUYV...."? Exactly what does it mean ? Does datasheet wrote as right?

Q2.Exactly, how does yuv420 real cameara make the output?

The subsample code letters for the suffix numbers are J:a:b for YUV J:a:b

J: horizontal sampling reference (width of the conceptual region). Usually, 4.
a: number of chrominance samples (Cr, Cb) in the first row of J pixels.
b: number of changes of chrominance samples (Cr, Cb)
between first and second row of J pixels.


Thus YUV420 uses 4H samples with 2 samples of Cr,Cb in the 1st of 3 rows with 0 between 1st & 2nd row.

The Omnivision specifies the formatter output sequence is correctly given as:

Like SECAM, 4:2:0 only stores and transmits one color channel per line (the other channel being recovered from the previous line.