The present invention is to provide a decoder which detects a start code in a layered coded data stream on a layer basis.
The decoder includes a unique pattern detector which detects a start code pattern in the layered coded data stream, a start code identifier which identifies the detected start code pattern based on a given condition, a similarity calculator which calculates similarity as an evaluation between an erroneously detected start code pattern and an expected start code based on layer, and a similarity based replacement identifier which replaces the erroneous start code pattern by the most appropriate replacement selected based on the similarity based evaluation, and otherwise the priority based replacement identifier which selects a replacement by the priority order.