This paper describes a publicly available database of subjective scores, relative to quality assessment of 156 video streams encoded with H.264/AVC and corrupted by simulating packet losses over an error-prone network. The data has been collected in controlled test environments at the premises of two academic institutions. A detailed statistical analysis of subjective results has been performed, showing high consistency of the collected scores. In addition to subjective scores, we have made available to the research community both the uncompressed files and the H.264/AVC bitstreams of each video sequence, in order to provide a common database of benchmark data to test and compare the performance of full-reference, reduced-reference and no-reference video quality assessment algorithms.