Abstract: An apparatus and concomitant method for creating and applying an encoded bitstream to evaluate the performance of a black box video decoder. The encoded bitstreams are designed such that the results from the DUT can be evaluated without the need of a human observer. The method applies the encoded bitstream to both a DUT and a compliant reference decoder and compares the results from both decoders to determine compliance of the DUT. Additional embodiments address postprocessing and the selection of a subset of test frames for evaluation.

Abstract: A method and apparatus for watermarking an image or sequence of images without limiting the watermark signal. The watermarking apparatus includes a conventional DCT unit and quantizer for generating an array of quantized DCT coefficients. The array is watermarked by masking the array to select certain ones of the DCT coefficients that are then replaced by zero values to form a masked array. The masked array is further processed by a watermark inserter that replaces the zero valued coefficients with predefined watermark coefficients to form a watermarked array of DCT coefficients, e.g., a watermarked image. A decoder for decoding the bitstream thusly generated and for removing the embedded watermark is also taught.

Abstract: A method and apparatus for creating and using an encoded bitstream to evaluate a video decoder. The bitstream contains a sequence of pictures or frames such that when a video decoder decodes the bitstream correctly, a desired visible pattern is produced on a video display. Specifically, various display parameters or flags are varied in the bitstream to test the video decoder's ability to implement display features such as "3:2 pulldown". For example, the bitstream is capable of demonstrating incorrect decoding of the top.sub.-- field.sub.-- first and repeat.sub.-- first.sub.-- field flags by a MPEG compliant video decoder.