What OEB is
Open eBook (OEB) 1.2 was one of the first open standards for electronic books. A book is a bundle of XHTML pages described by a package file that lists its contents, reading order, and descriptive information. It was the forerunner of the EPUB format used by today’s e-readers, and it is still referenced by some archives, libraries, and publishing pipelines that handle older material.
What PDF to OEB creates
PDF Studio extracts the text of every page and builds a ZIP container, saved with an .oeb extension, that holds one XHTML file per PDF page, an oeb.package manifest in OEB 1.2 format with Dublin Core metadata (title, creator, and similar descriptive fields), and a simplified content.opf file for readers that expect that name. Pages are listed in reading order.
The conversion runs in your browser, so the PDF is not uploaded.
Limits to know about
The content is text only. Images, drawings, fonts, and the original page layout are not included, and each PDF page becomes its own XHTML page, so book-style flow across pages is not rebuilt. Scanned PDFs contain no text, so run OCR PDF first. Mainstream e-readers and apps do not open OEB 1.2 directly, so expect to use it with specialist software or a conversion step.
When it is the right choice
Choose PDF to OEB when a workflow explicitly asks for OEB 1.2, or for archiving text in an open, XML-based structure. If you only want to read a book on an e-reader, a plain text file from Extract Text or an editable version from PDF to Word is usually more practical.