The main element of the user interface is a slider that is used to choose the video source file among n sequences with different quality level, together forming an adjustable video sequence.
When a sufficient number of test subjects have performed the test, the average quality of the sequences chosen by the subjects is supposed to describe the quality level of the adjustable sequence that is perceptually equivalent to the quality level of the fixed sequence.
In the second study, reported first in [8], the roles of the fixed and adjustable sequences were swapped: the level of channel distortion was adjusted instead of source distortion.
The 16 different adjustable sequences contained different levels of source distortions (i.e., each one encoded with different QP).
In total, there were 12 fixed sequences (4 contents × 3 fixed QP levels) and 132 adjustable sequences (4 contents × 3 fixed QP levels × 11 BER levels).
This resulted in 40 fixed sequences (10 contents × 4 fixed QP levels) and 160 adjustable sequences (10 contents × 16 fixed QP levels).
These quality metrics were performed either between the distorted sequences (fixed or adjustable sequences) and the original, undistorted sequences (for PSNR, VQM, MOVIE, and SSIM), or on the distorted sequences alone (for NRIQM), in order to objectively evaluate the quality of the fixed and adjustable sequences against the original versions.
Sample frames of these contents are shown in Figure 3. Six different combinations of QPs were used for the fixed and adjustable sequences (see Table 2).
In order to evaluate the overall performance of each metric, we have computed the root mean squared error (RMSE) between the normalized quality values of the fixed sequences and the normalized mean quality values of the adjustable sequences in each test case.
It is capable of compiling RNA sequences for a given structure that comply in addition with an adjustable full range objective GC-content distribution, specific sequence constraints and additional fuzzy structure constraints.
This engine has an adjustable compression ratio (CR), an adjustable ignition timing, and the capability to test fuels in sequence [8, 9].
