The direction in which the sample is to be played.
This is similar to loop_type but affects the entire sample, not just the defined loop regions.
At least in ARIA, direction=reverse doesn't always work as expected. However, it seems to work if the sample= opcode is specified for every region. Specifying the sample at the group header level and then specifying direction under the region doesn't seem to work at least in cases where one region has the sample playing forward, and another region has the same sample playing backwards.
Category: Sound Source, Sample Playback