Is it possible to use mpeg dash within a single file?

Question

YouTube

It is required to download a video from YouTube, and then make it possible to view a set of its ranges through the client browser.
/It seems/ this can be solved by creating an .mpd file according to the dash-mpeg standard, listing the necessary periods, which will be glued into one video simply due to the fact that the necessary parts of this video will be downloaded.

The problem is that it is impossible to figure out how to start the next period not from the beginning, but from the desired time stamp. The documentation has a presentationTimeOffset parameter, but I don’t understand how to apply it to a video that is not physically chopped into chunks.

Please let me know if this is possible at all.