Performance analysis of HEVC-based Intra coding for still image compression

Preliminary performance comparisons between the current test model encoder of the upcoming high efficiency video coding (HEVC) standard and an H.264/AVC High Profile conforming encoder report average bit-rate savings of about 40% and 25% for a random-access and an all-intra configuration, respectively. Even though H.264/AVC and HEVC are primarily designed for video coding applications, it might be interesting to find out how their corresponding intra-coding tools perform when applied to still images, especially when compared to current state-of-the-art still image coding standards. To this end, we evaluated the intra-only coding modes of HEVC and H.264/AVC together with popular image-coding standards like JPEG, JPEG 2000, and JPEG XR as well as the proprietary WebP scheme. By using a representative test set of photographic still images, we obtained a clear ranking in terms of objective coding performance with average bit-rate savings in the range of 17-44% for HEVC intra-only coding relative to all other competing coding schemes.