You can output archives in both single- and multiple-frame mode. Single-frame archives contain only enough data to render a single frame (or a pair of fields) whereas a multi-frame archive contains enough render data to render a whole sequence from a single file.
In both cases the Process callback gets called for individual frames so it is up to the renderer plug-in to maintain enough state information between calls to properly output multiple frames to a single archive.
In each case, the filename to use for each frame is provided in the "ArchiveFileName"context attribute. For multi-frame archives, this is always the same value for all frames in the sequence.
Multi-frame archive support is optional and is enabled by calling Renderer::PutArchiveFormat and passing a value of true to the in_bMultiFrame argument.