mj2_video_target::access_channels

Provides an interface which may be used to specify the relationship between code-stream image components and colour reproduction channels (colour intensity channels, opacity channels, and pre-multiplied opacity channels). This information is used to construct appropriate JP2 "Component Mapping" and "Channel Definition" boxes. The information is fixed for all frames in the video track.

It is NOT NECESSARY to access or initialize the jp2_channels object directly; the default behaviour is to assign the colour intensity channels to the initial code-stream image components. That is, the first code-stream component is assigned to the luminance or red intensity, the second is assigned to the green intensity, and the third is assigned to the blue intensity. The mandatory information configured in the jp2_colour object is used to determine whether a luminance or RGB colour space is involved.