How can the following NTSC video signal be interpreted? Is it using phases or frequencies or amplitudes?

[![enter image description here](https://i.stack.imgur.com/eue8i.png)](https://i.stack.imgur.com/eue8i.png)

Is this above only the color information of a video broadcast signal?

I have no background on this type of communication. Is H-BLANKING indicating where the data chunk is finished? I guess the active video period carries color information? chrominance and luminance looks the same frequency. How would the encoder know which one is what? How about peak white?