CONTENTS

RECOMMENDATION  ITU-R  BS.1770-1     1
Algorithms to measure audio programme  loudness and true-peak audio level     1
Scope     2
Annex 1  Specification of the objective multichannel  loudness measurement algorithm     3
Appendix 1 to Annex 1  Description and development of the multichannel measurement algorithm     6
1 Introduction  6
2 Background  7
3 Design of the Leq(RLB) algorithm   8
4 Subjective tests  9
        4.1 Subjective test set-up  9
        4.2 The subjective database  10
5 Design of the multichannel loudness algorithm   12
6 Evaluation of the multichannel algorithm   13
Annex 2  Guidelines for accurate measurement of “true-peak” level     16
1 Summary  16
 2     Block diagram   16
3 Detailed description  17
Appendix 1  to Annex 2  Considerations for accurate peak metering of digital audio signals     17
What is the problem?     17
How bad can the problem be?     18
What is the solution?     19
How should a true-peak meter be implemented?     20