Improved error resiliency of an encoding device, such as a video codec or encoder, operating in a compressed data transmission system, is achieved by enabling the encoding device to "shadow" or mimic the error conditions of a decoding device that receives and decodes compressed data sent by the encoding device. The encoding device is made aware of the specific error concealment scheme that the decoding device employs to reconstruct video frame data from a bit stream that contains bit or packet errors, and is also made aware of the location(s) in the frame to which the erroneous data corresponds and the particular manner in which the erroneous data was handled. The error-concealed data then can be used not only for the present encoding, but for subsequent encodings as well, to achieve synchronization between the encoder and decoder. Advantageously, the present invention improves on, but can work with, conventional error concealment schemes.