For the new HEVC compression technology, the analysis of accumulation of quality losses in multi-generation coding is still an open problem. In this paper, we describe the results of extensive experiments that demonstrate quality loss accumulation in 300 encoding-decoding cycles using the HEVC codec in the All Intra mode. For consecutive encoding cycles with constant encoder configuration, the coding quality loss decrease much slower than for JPEG 2000. However, for SD resolution, the HEVC intra-only encoder provides lower bitrates than JPEG 2000 with the same video quality. Therefore, even after 300 cycles, the HEVC All Intra usually provides lower bitrates than JPEG 2000 with the same decoded-video quality.