I'm trying to find a standard (or, at least, not completely obscure) binary data format with which to represent an X/Y/Z+R/G/B point cloud, with the added requirement that I need to have some additional metadata attached to each point. Specifically, I need to attach zero or more "source" attributes, each of which is an integer, to each point.
Is there an existing binary data format which is well-suited to this? Or, perhaps, would it be wiser for me to go with two separate data files, where the metadata just refers to the points in the cloud by their index into the full list of points?
From what I can tell, the PLY format allows arbitrary length lists of attributes attached to each element and can have either ASCII or "binary" format: http://www.mathworks.com/matlabcentral/fx_files/5459/1/content/ply.htm
As far as I know, PCD only allows a fixed number of fields: http://pointclouds.org/documentation/tutorials/pcd_file_format.php