How do I force the browser to download a file to disk. : Sometimes linking directly to audio or video files can cause problems because the website isn't fast enough to support "streaming" video playback on the fly.
Or users may have trouble with videos in their browser, but no trouble when they access them from their desktop. Or perhaps you just want to invite the user to save a text file or an image, rather than displaying it in the browser window. O forçar o download de um arquivo em PHP, por Oberaldo Bull.