Intra-Frame and Inter-Frame Data
Intra-frame data is used when you need to use or display a value from a lower layer in a higher layer decoder. Inter-frame data is used when you need to use a value from a prior frame in the current frame. A major difference is that the intra-frame data is saved for the duration of the frame; inter-frame data is saved until it's changed or we run out of frames. By contrast, the STORE keyword discussed earlier stores data only for the duration of the layer. We'll start by talking about intra-frame data.