RPF : codec / non-codec terminology

[llemeurfr]

The terms codec / non-codec are used in the RPF packaging format specification. They find their source in the EPUB spec and found their way in the LPF spec.

Codec, in practice, indicates that the content is already optimized for compression and may be streamed, therefore should not be deflated in the zip file. Non-codec designates other types of resources.

The chosen terms may therefore not be the best. Should we change this terminology, e.g. for "binary" vs "textual"?

Note that a PDF resource is already compressed and therefore does not need further compression in the zip. But a PDF is not really a "binary" resource.

Note also that changing the terminology could be an issue for developers who read both the W3C (EPUB and LPF) and Readium specification.