MpegView is a Mac app that will allow you to view the internal structure of an MPEG2 elementary stream or program stream.
As you zoom in additional information about the specific packet you are viewing will be displayed.
Use the arrow keys or mouse wheel to zoom in, zoom out, scan left or scan right. Clicking on a specific packet will show more information about that packet.
NOTE: MpegView can only be purchased via the Mac App Store (the buy link redirects you to its App Store page). To purchase/download applications via the App Store an Apple account is required.