The video really sounds like it was taped in advance in reference to this gamaa islamiya release.
I'll be looking for the text. I'm flying blind on this one as I don't know Arabic. So I have to wait for a translation, but it sounds "familiar" . . .
"In the footage, al-Zawahri appears sitting, wearing a white turban and a grey robe with a microphone pinned to it. An automatic weapon is leaning against a brown backdrop behind him."