Subjective assessment of HDTV content: comparison of quality across HDTV formats

This paper reports on a series of experiments designed to examine the subjective quality of HDTV encoded video. A common set of video sequences varying in spatial and temporal complexity will be encoded at different H.264 encoding profiles. Each video clip used in the test will be available in 720p, 1080i and 1080p HDTV formats. Each video clip will then be encoded in CBR mode using H.264 at bitrates ranging from 1 Mbit/s up to 15 Mbit/s with the other encoding parameters identical (e.g., identical key frame intervals and CABAC entropy mode). This approach has been chosen to enable direct comparison across bit-rates and formats most relevant to HDTV broadcast services. Three subjective tests will be performed, one test for each HDTV format. The single-stimulus subjective test method with the ACR rating scale will be employed. A total of 15 non-expert subjects will participate in each test. A different sample of subjects will participate in each test, making 45 subjects in total. The test results will be available by end of the summer 2009.