"498 In summary, the record and findings of the District Court lead us to two conclusions. First, Sony demonstrated a significant likelihood that substantial numbers of copyright holders who license their works for broadcast on free television would not object to having their broadcasts time- shifted by private viewers. And second, respondents failed to demonstrate that time-shifting would cause any likelihood of nonminimal harm to the potential market for, or the value of, their copyrighted works. The Betamax is, therefore, capable of substantial noninfringing uses. Sony’s sale of such equipment to the general public does not constitute contributory infringement of respondent’s copyrights."