Target Loudness Level and Dynamic Range

Transcription

1 Gerhard Spikofski GmbH Research and Development Institute of ARD, ZDF, Dradio, ORF and SRG/SSR Target Loudness Level and Dynamic Range 3rd International VDT Symposium An Eye on Hearing Schloss Hohenkammer Bavaria Oct. 30th - Nov.1st

2 Overview Programme Level Normalisation Loudness Level Normalisation Definitions Target Loudness Longtime/Shorttime Loudness Loudness Range Loudness Range and Listening Level Conclusions

3 Programme Level Normalisation

4 Programme meter specifications stereo IEC Type IIa IEC Type I BBC IEC-II IEC

5 Programme meter specifications MCA IEC Type I

6 Programme meter specifications Quasi Peak Programme Meter QPPM (IEC , ARD-Pflichtenheft 3/6) Modulation Range Headroom programme level 9% 35% 100% 180% 10 ms 90% indication -51 relative level db 10 ms 90% indication R -60 digital Level dbfs -45 analogue Level ITU-R dbu -45 analogue Level ARD dbu L EBU- Alignment Level Technical guidelines of TV-productions, HFBL-K

7 Recommendations Meter: IEC , ARD-Pflichtenheft 3/6 QPPM t i = 10 ms (level control) PPM t i = 0 ms (peak control) Level: R68 (EBU), Headroom in digital audio (ARD), Technical guidelines of TV-productions (ARD/ZDF/ORF) QPPMmax = 100% = -9 dbfs!!! PPMmax = -3-6 dbfs

8 Loudness Level Normalisation

9 Algorithm Recommendation ITU-R BS.1770 LKFS RMS Prefilter + RLB-Filter = K-Filter Seite 9

10 LM100 Broadcast Loudness Meter, Dolby Seite 10

11 DP 600 Programme Optimizer, Dolby Seite 11

12 Surround Monitor 11900, RTW Seite 12

13 Surround Loudness Meter with Datalogger (Ldn Server/Viewer), Pinguin

14 Ldn Normalizer, Pinguin

15 LM5 Loudness Radar Meter, TC electronic Seite 15

16 Seite 16

17 Seite 17

18 Seite 18

19 Does loudness normalisation constrain sound engineer s creative work, his scope for design?

20 Measurements on P/LOUD test item pool 27 Wide loudness range (WLR) 20 Narrow loudness range (NLR) 12 Speech based (SP) 5 Mixed content (MXD) 13 Music based (MUS) 77 Total Seite 20

21 Target Loudness Longtime/Shortime Gated/Ungated Gating Treshhold Loudness Range

22 LKFS Loudness parameters Longtime: LKFS average from start to stop (e. g. whole file) Shorttime/Monotoring: LKFS average over 3 s and 10 s Ungated: reading the entire signal Gated: excluding low loudness passages (e. g. 6 LKFS below target level) Loudness range: ratio between maximum and minimum LKFS level (3 s) (e. g. 95th and 5th percentile) Seite 22

23 Measurements on the P/LOUD test item pool Seite 23

24 Measurements on the P/LOUD test item pool Seite 24

25 Target Loudness = -23 LKFS

26 Measurements on P/LOUD test item pool All items normalized to the (still) valid reccomendation QPPMmax (10 ms) = -9 dbfs Can each item - especially WLR - be adapted to the target loudness -23 LKFS? Seite 26

27 Measurements on P/LOUD test item pool Seite 27

28 Measurements on P/LOUD test item pool Seite 28

29 Loudness Range

30 Measurements on P/LOUD test item pool Seite 30

31 Measurements on P/LOUD test item pool Seite 31

32 Loudness range and Listening level

33 SMPTE RP 200 Relative and Absolute Sound Pressure Levels for Motion-Picture Multichannel Sound Systems (fixed) Measuring signal Pink noise SPL/speaker Left Center Right Left Surround Right Surround Total SPL -20 db RMS 85 dbc 85 dbc 85 dbc 82 dbc 82 dbc 91 dbc

34 SMPTE RP 200 (Draft) Home cinema (fixed) Measuring signal Pink noise SPL/speaker Left Center Right Left Surround Right Surround Total SPL -20 db RMS 77 dbc 77 dbc 77 dbc 74 dbc 74 dbc 83 dbc

35 EBU Tech Reference listening level broadcast (variable!) Measuring signal Pink noise SPL/speaker Left Center Right Left Surround Right Surround Total SPL -18 db RMS 78 dba 78 dba 78 dba 78 dba 78 dba 85 dba

36 Differences between EBU Tech and SMPTE RP 200 dba/channel dba/all dbc/channel dbc/all EBU Tech SMPTE RP200 77dBC SMPTE PR200 85dBC

37 Dynamic range of original sources Ratio between maximum and minimum SPL Respectively programme level fff = 100 dba / -9 db QPPM ppp = 40 dba / -69 db QPPM Dynamic range = 60 db

38 Loudness range of original sources Ratio between maximum and minimum SPL respectively Loudness level LKFS fff = 100 dba / -6 LKFS ppp = 40 dba / -66 LKFS Loudness range = 60 LKFS

39 Control room/listening level 0 db Dynamic range of reproduction environment (DRR) > 50 db -23 LKFS

40 Car environment/listening level 0 db DRR > 25 db fff ppp Noise floor -23 LKFS

41 ipod/listening level -10 db DRR < 20 db Noise floor -23 LKFS

42 City appartment/listening level -20 db DRR > 30 db Noise floor -23 LKFS

43 Loudness range needs to be adapted to DRR!

44 Solution: Variable dynamic range by means of a transmitted dynamic control signal G. Plenge, G. Spikofski, G. Theile "Variable dynamic range: a method for improving the sound broadcasting and television service". EBU - Review - Techn. No. 218, 1986, S

45 Solution: DRC in the receiver X

46 Solution: DRC in the receiver X

47 Conclusions Loudness normalisation at target level -23 LKFS introduces negligible constrains with respect to loudness range Loudness normalisation cannot solve adaptation of programme loudness range to dynamic range of reproduction environment A programme loudness range compromise could be 20 LKFS Sound engineers should not be biased in their aesthetic producing Certainly special audio productions need higher loudness range Adaption to reproduction environment can be achieved by transmission of metadata and/or DRC in the receiver

48 Vielen Dank für Ihre Aufmerksamkeit Gerhard Spikofski Audiosystemtechnik Floriansmühlstraße München Tel. +49-(0) Fax +49-(0) Die Folien/Dokumente sind durch das Urheberrecht geschützt. Eine Vervielfältigung ist nur mit Genehmigung des Verfassers gestattet. Dieser Urheberrechtshinweis darf nicht entfernt werden.