CONTENTS

Policy on Intellectual Property Right (IPR)     v
RECOMMENDATION  ITU-R  BT.500-12     1
Methodology for the subjective assessment of the quality of television pictures     1
Scope     1
Annex  1  Description of assessment methods     2
1 Introduction  2
2 Common features  2
        2.1 General viewing conditions  2
                  2.1.1 Laboratory environment 3
                  2.1.2 Home environment 3
                  2.1.3     Monitor resolution  5
                  2.1.4     Monitor contrast 5
        2.2     Source signals  6
        2.3     Selection of test materials  6
        2.4 Range of conditions and anchoring  7
        2.5 Observers  8
        2.6 Instructions for the assessment 8
        2.7 The test session  8
        2.8     Presentation of the results  9
 3     Selection of test methods  9
 4     The double-stimulus impairment scale (DSIS) method (the EBU method) 10
        4.1     General description  10
        4.2     General arrangement 11
        4.3     Presentation of the test material 11
        4.4     Grading scales  11
        4.5     The introduction to the assessments  12
        4.6     The test session  13
 5     The double-stimulus continuous quality-scale (DSCQS) method  13
        5.1     General description  13
        5.2     General arrangement 13
        5.3     Presentation of the test material 13
        5.4     Grading scale  14
        5.5     Analysis of the results  16
        5.6     Interpretation of the results  16
 6     Alternative methods of assessment 16
        6.1     Single-stimulus (SS)  methods  16
                  6.1.1     General arrangement 16
                  6.1.2     Selection of test material 17
                  6.1.3     Test session  17
                  6.1.4     Types of SS methods  18
        6.2     Stimulus-comparison methods  19
                  6.2.1     General arrangement 19
                  6.2.2     The selection of test material 19
                  6.2.3     Test session  19
                  6.2.4     Types of stimulus-comparison methods  19
        6.3     Single stimulus continuous quality evaluation (SSCQE) 20
                  6.3.1     Continuous assessment of overall quality  21
                  6.3.2     Calibration of continuous quality results and derivation of a single quality rating     22
        6.4     Simultaneous double stimulus for continuous evaluation (SDSCE) method  23
                  6.4.1     The test procedure  24
                  6.4.2     The different phases  24
                  6.4.3     Test protocol features  25
                  6.4.4     Data processing  25
                  6.4.5     Reliability of the subjects  26
        6.5     Remarks  28
Appendix  1 to  Annex  1  Picture-content failure characteristics     28
 1     Introduction  28
 2     Deriving the failure characteristic  28
 3     Use of the failure characteristic  30
Appendix  2 to  Annex  1  Method of determining a composite failure characteristic for programme content and transmission conditions     31
 1     Introduction  31
 2     Programme-content analysis  31
 3     Transmission-channel analysis  32
 4     Derivation of composite failure characteristics  32
Appendix  3 to  Annex  1  Contextual effect     33
Annex  2  Analysis and presentation of results     33
 1     Introduction  33
 2     Common methods of analysis  34
        2.1     Calculation of mean scores  34
        2.2     Calculation of confidence interval 34
                  2.2.1     Processing of raw (uncompensated and/or unapproximated) data  34
                  2.2.2     Processing of compensated and/or approximated data  35
        2.3     Screening of the observers  35
                  2.3.1     Screening for DSIS, DSCQS and alternative methods except SSCQE method  35
                  2.3.2 Screening for SSCQE method  36
3 Processing to find a relationship between the mean score and the objective measure of a picture distortion     38
        3.1 Approximation by a symmetrical logistic function  38
        3.2 Approximation by a non-symmetrical function  39
                  3.2.1 Description of the function  39
                  3.2.2 Estimation of the parameters of the approximation  39
        3.3     Correction of the residual impairment/enhancement and the scale boundary effect 40
        3.4     Incorporation of the reliability aspect in the graphs  41
 4     Conclusions  42
Annex  3  Description of a common inter-change data file format     43