Steganographic signals or digital watermarks are detected from media signals. A media signal may represent audio, video or imagery. In one implementation, a method of detecting a digital watermark in a media signal is provided. The method includes receiving blocks of the media signal; buffering the blocks; screening the blocks for a presence of the digital watermark to identify a plurality of blocks likely to include the digital watermark based on a detection metric; combining the blocks that have been identified as being likely to include the digital watermark; and detecting the watermark from the combined blocks. Other implementations are provided as well.