Stream

Consider the sign language domain once again. Each training instance consists of the individual channels. It is convenient to talk of all of the channels collectively. For example, Figure 2.1 shows a number of channels, but we want to talk about all of the channels at once. This is the definition of a stream.

A stream is a sequence of channels S, such that the domain of each channel in S is the same, i.e.

$$S = [c_1, c_2, ..., c_n]\ \mathrm{s.t.}\ \mathrm{domain}(c_1) = \mathrm{domain}(c_2) = ... = \mathrm{domain}(c_n)$$

where $n$ is the number of channels in the stream S. Each channel has the same domain - this corresponds to the timepoints where samples of each of the channels exist.

A stream allows us to collect all these various measurements and treat them, in some ways, as part of the same object. The Tech Support domain is very simple: each training stream has one channel. However, the Auslan domain has eight.