This paper advances SPYART, a novel semi-fragile watermarking scheme for MPEG-4 AVC protection. The authentication information, granting the method fragility, is provided by the Intra prediction mode types. This signature is embedded in the quantized error prediction of the DCT coefficients by an m-QIM technique, thus ensuring the method robustness. SPYART was evaluated under the framework of a videosurveillance application; the results exhibit fragility to content replacement (with an 1/81 frame and 3s spatial and temporal accuracy, respectively) and robustness against transcoding (MPEG-4 AVC compression by a factor of 4). As both the signature extraction and mark embedding take place at the MPEG-4 AVC syntax element level, the method also features low complexity.