Master clock in Traktor and external inputs

Someone correct me if I’m wrong but you would have to use timecode vinyls to sync your music with the master clock. You can select live input for a deck and spin vinyl through that but it is just a straight audio signal (what you would use if you want to spin some real vinyl with your digital tracks). Otherwise I think you would have to work out the tempo and set the master clock manually, making sure you time your button pressing and knob tweaking perfectly.