What is the difference between base64/ inputstream/ url?
Base64 returns a base64 encoded text blob in the JSON response that can be decoded into an image/document. This can be a maximum of 5 MB in size. If one has large media, then instead one should use a stream, which returns a file stream that can be saved directly. If one has a URL to a media, it can be used to save the media.
What is the difference between sourceID and import code?
When importing media via the media import API, one can specify a sourceID for the media upon import. This can also be used later for editing/exporting. This sourceID exists only if set during import and therefore may not always be available. ImportCode is feed®'s internal and unique ID sequence number for media and is always accessible and unique.