An A/V mixer is very different from a standard video mixer in that it has an audio component to it. The Roland VR-3EX is no exception. On the left side, it has a full audio console with many inputs, ...
For each channel, you can specify streaming options. I’m streaming to Ustream (Figure 7, below), using encoding options chosen in the Encoding screen shown in Figure 8 (below Figure 7). Figure 7.