Does such a thing exist or perhaps just in Rome? Is there a place online that has audio and video files from Papal visits and speeches? I’m specifically trying to find the audio or video to Pope John Paul II’s opening remarks at the cathedral in San Salvador in 1996.
I’m not sure about audio and video files, particularly from that long ago. I have noticed that, prior to December 1996, there are much, much fewer English translations of papal documents (such as speeches, homilies, general audiences, etc.). Only the major documents (encyclicals, and the like) have been translated. My guess is that it was at about this time that the Vatican really started paying attention to their website.
You can search under John Paul II for his Travels. From there, you can scroll down to 1996 and find his trip to Guatemala, Nicaragua, El Salvador and Venezuela. And from there, you can see his opening remarks in front of the Cathedral. But, that only helps you if you can read Spanish or Italian as there is no English translation. I have tried various online translation tools before, but I haven’t found one that works well with documents from the Vatican website. Those tools tend not to understand the vocabulary of the Church.
You can find video and audio for recent trips, such as Benedict’s 2008 trip to the US (here or here). But when it comes to things from several years back, I think you may (unfortunately) be out of luck.