The present disclosure relates generally to digital watermarking and steganography. One claim recites a method including: receiving digital data representing media including at least video and audio; digital watermarking at least some portions of the digital data, the digital watermarking introducing changes to at least some portions of the digital data to hide information in at least some portions of the digital data representing audio and in at least some portions of the digital data representing video, the information comprises at least geo-location data and time data, and the geo-location data is redundantly hidden in digital data over time; and optically projecting the media on a surface for viewing. Projected media includes the information digital watermarked therein. Of course, other claims and combinations are provided as well.