I am having a hard time understanding how to calculate the data rate when leveraging chroma-subsampling in e.g. a Y'UV image:
I have the following examples for a calculation:
Frequency: 25 fps
For (4:4:4) the example calculation goes as follows:
(352px * 288px) * 3 color channels * 25 fps * 8 bit = 60 825 600 bit/s
So far so good.
But now comes (4:2:0):
(352px*288px) * 1.5 color channels * 25 * 8 = 30 412 800 bit/s
Now, trying to transfer this example to e.g. (4:1:1) I realized I am not sure whether I have a correct understanding how the ratio of 1.5 color channels is being calculated.
My first guess for the calculation was in case of (4:2:0):
2/4*3=1.5 color channels
Likewise for (4:1:1) I would calculate the ratio for the color channels as:
1/4*3=0.75 color channels
But I am simply not sure whether this would be the correct way to go.
As an alternative, I was thinking along following lines:
color channels (4:1:1):
1 Y' + 1/4 UV = 1.25 color channels
Now which would be the correct way of doing this properly?