Félix Poulin Société Radio-Canada. Michel Lavoie Centre de Recherches sur les Communications. Jean-Claude Krelic Miranda Technologies

Transcription

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2 Félix Poulin Société Radio-Canada Michel Lavoie Centre de Recherches sur les Communications Jean-Claude Krelic Miranda Technologies

3 Loudness Control Solutions For Television Miranda Technologies

4 Part 1: Background information Dolby Digital (AC-3)

5 How We Used To Manage Loudness and Dynamic Range Original Dynamic Range Audio Compresser Limiter Restricted Dynamic Range Analog Audio TX Restricted Dynamic Range

6 Loudness and Dynamic Range in AC-3 Original Dynamic Range AC-3 Encoder Audio Analysis AC-3 Bit Stream AC-3 Decoder Original Dynamic Range Program Audio Bit Rate Reduction DRC data Audio Samples Pgm. Meta Data Audio Decode Dynamic Range Processor Gain Stage Program Meta Data Static Defaults DYNRNG DIALNORM Viewer Listening Mode

7 Original Dynamic Range Can Be Heard if Desired dbfs 0 ORIGINAL Content User Mode= NARROW User Mode= FULL AC-3 Decoder Audio Decode Dynamic Range Processor Gain Stage DynRng Viewer Listening Mode

8 Dial Norm Value is Used To Match Up Levels AC-3 Decoder Audio Decode Dynamic Range Processor Gain Stage DIALNORM

9 Dialog Normalization Dialog normalization keeps average loudness uniform between program segments Eliminates need to change volume control between program segments or when changing channels (or media) When Dialnorm values are correctly provided, user should not need to adjust the volume When Dialnorm values are not properly provided, user will need to adjust the volume

10 Typical Programs 0 dbfs -10 dbfs ACTION MOVIE DRAMA SPORTS SYMPHONY ROCK NEWS LD MOVIE VHS HI-FI DSS PPV CLASSICAL POP CD TV AUDIO dbfs -30 dbfs dbfs AVERAGE DIALOG SIGNAL PEAKS

11 Dialogue Level (dialnorm) 0 dbfs Action Movie Drama Sports Sitcom Talkshow News LD MOVIE VHS HI-FI DSS PPV CLASSICAL POP CD TV AUDIO -10 dbfs -20 dbfs -30 dbfs -40 dbfs AVERAGE DIALOG SIGNAL PEAKS

12 Loudness is a Long term Measure Loudness Varies as natural part of program Average AC-3 DIALNORM Loudness for Entire Value Content Duration of Program Dynamic Range of Content 1. The instantaneous loudness of a program will vary as part of the intended creative of the content 2. Properly mixed content will stay within a given range and the overall average loudness will be known and controlled 3. The DIALNORM Value should express the average loudness of the content

13 Dialnorm Value corresponds to loudness of Anchor Element DIALNORM Value

14 The Loud Commercial Effect DIALNORM Value DIALNORM Value

15 The Meta Data Concept Broadcast Facility Meta Data Terrestrial Tx, Cable, Sat, IPTV or DVD HDTV Home DIALNORM Value L,R LS,RS C LFE AC-3 Emission Encoder Dolby Digital (AC-3) Data Stream Demux and decode AC-3 Decoder Gain Stage 5.1 Ch Amp

16 Loudness Normalization using DIALNORM Program is shifted by post decode processing to Align the two DIALNORM Values

17 Loudness Normalization using DIALNORM This is equivalent to having turned down the volume on your amplifer This has NOT altered the Dynamic Range of the Content

18 When Does This Concept Break Down

19 The Effect Of Wrong Meta Data DIALNORM Level DIALNORM Value

20 Loudness Normalization using DIALNORM Because of wrong Meta Data This Program will be louder than other programs

21 Key Meta Data Parameters Focus Chan Mode: tells the decoder whether the coded stream is 5.1, stereo, mono, etc. Downmixing: Allows the decoder to do a proper downmix Center channel mix level default = -3 db Surround channel mix level default = -3 db Dialogue Level (DIALNORM) Controls a 1 db/step attenuator in all consumer decoders Used to match program-to-program loudness Dynamic range (DYNRNG) Determines the type of dynamic range control that will be applied by decoder Dynamic Range Control (DRC) Values generated by encoder, selectively applied by consumer decoders

22 Two Different Loudness Problems 1. Segment to Segment Loudness at Broadcasters 2. Channel to Channel Loudness at Distributor (Cable, Satellite or IPTV Operator)

23 Segment to Segment Audio Loudness At Broadcaster IRD Proc Emission IRD files Ingest Proc Server Routing Master Control Audio and Video Encode Production OB Remote Production Proc

24 The Audio Loudness Problem IRD Proc -24 dbfs IRD files Ingest Proc -24 dbfs -27 Server dbfs -22 dbfs Routing Master Control Emission dbfs Audio and Video Encode Fixed DIALNORM Value Production -24 dbfs -24 dbfs OB Remote Production Proc -27 dbfs

25 The Challenge Multiple Segments Instantaneous Loudness Dynamic Range of Content Long Form Program DIALNORM Value

26 The Challenge Multiple Segments Instantaneous Loudness Dynamic Range of Content Long Form (Program) Segment N DIALNORM Value Short Long Form Program (Commercial / Promo) Segment N+1 Long Form Program Segment N+2

27 The Challenge Instant and Multiple Segments Dramatic Swing In Loudness Long Form (Program) Segment N Short Form (Commercial / Promo) Segment N+1 Long Form Program Segment N+2 DIALNORM Value Not Changed During Short Form Segment

28 The Challenge Multiple Segments Long Form (Program) Segment N Short Form (Commercial / Promo) Instant Segment and Non Matching N+1 Dramatic Average Swing In Loudness Loudness Long Form Program Segment N+2

29 The Challenge Multiple Segments Non Compatible Dynamic Range Long Form (Program) Segment N Short Form (Commercial / Promo) Segment N+1 Long Form Program Segment N+2

30 Two Different Loudness Problems 1. Segment to Segment Loudness at Broadcasters 2. Channel to Channel Loudness at Distributor (Cable, Satellite or IPTV Operator)

31 High Level View of Loudness Situtation in IPTV and Cable Systems 1 2 Avg. Loudness: -24 db and Consistent DIALNORM = -24 dbfs Fixed Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed DIALNORM is used to automatically adjust STB audio output level to correct for inter-channel loudness differences 3 4 Avg. Loudness: -20 db and Consistent DIALNORM: -24 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System MPEG AC3 Video Decode AC3 Decode Gain Stage Volume Control Speakers 5 Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment DIALNORM Home Set Top Box AV System or TV 6 Avg. Loudness: Varies by Segment DIALNORM: -24 db Fixed 7 Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

32 High Level View of Loudness Situtation in IPTV and Cable Systems 1 Avg. Loudness: -24 db and Consistent DIALNORM = -24 db Fixed 2 Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed 3 4 Avg. Loudness: -20 db and Consistent DIALNORM: -24 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System MPEG AC3 Video Decode AC3 Decode Gain Stage Volume Control Speakers 5 Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment DIALNORM Home Set Top Box AV System or TV 6 Avg. Loudness: Varies by Segment DIALNORM: -24 db Fixed 7 Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

33 High Level View of Loudness Situtation in IPTV and Cable Systems 1 Avg. Loudness: -24 db and Consistent DIALNORM = -24 db Fixed 2 Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed 3 4 Avg. Loudness: -20 db and Consistent DIALNORM: -24 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System + MPEG AC3 Video Decode AC3 Decode Gain Stage Volume Control Speakers 5 Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment DIALNORM Home Set Top Box AV System or TV 6 Avg. Loudness: Varies by Segment DIALNORM: -24 db Fixed 7 Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

34 High Level View of Loudness Situtation in IPTV and Cable Systems 1 Avg. Loudness: -24 db and Consistent DIALNORM = -24 db Fixed 2 Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed 3 4 Avg. Loudness: -20 db and Consistent DIALNORM: -24 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System + MPEG AC3 Video Decode AC3 Decode Gain Stage Volume Control Speakers 5 Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment DIALNORM Home Set Top Box AV System or TV 6 Avg. Loudness: Varies by Segment DIALNORM: -24 db Fixed 7 Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

35 PART 2: ATSC A/85 RP Adopted

36 Bill to End Loud TV Ads Passes House (AP) A bill that would turn down the volume on loud television advertisements passed the House of Representatives Tuesday and has a sponsor in the Senate. The Commercial Advertisement Loudness Mitigation - or CALM - Act, championed by Rep. Anna Eshoo, D-Calif., passed by a voice vote.

37 CBS Early Show Report

38 Collaborators

39 ATSC A/85 Important Annex

40 ATSC A/85 Important Annex H

41 ATSC A/85 Important Annex H

42 Target loudness for content without metadata

43 Regulations and Laws around the world. ABA TV ad loudness recommendations premature THE Australian Broadcasting Authority s recommendation for a new code to address community complaints about the loudness of TV commercials is premature, according to the Federation of Australian Commercial Television Stations. New UK Ad Loudness Regulation The Broadcast Committee of Advertising Practice, part of Britain s Advertising Standards Authority (ASA), recently issued a regulation referencing proper sound levels in advertisements. The regulation advises engineers to employ a loudness meter during ad content creation, preferably one conforming to the ITU-R BS-1770/1771 standard. It goes on to state that if a loudness meter is not available, engineers must ensure that the peak level of this material be no higher than 6 db below the peak level of the surrounding program material. In the UK, program material peaks at +8 dbu, so ads must not peak at levels higher than +2 dbu.

44 Part 3: LOUDNESS MANAGEMENT STRATEGIES For Broadcasters

45 Loudness Management Strategies NEXT 1. Dynamic DIALNORM Meta Data 2. Establish Target Loudness, mix or preprocess all content to Target Loudness. 3. Process outgoing audio in real time to match Target Loudness

46 1. Dynamic Loudness Meta Data Contribution Production Emission IRD IRD Proc Proc Proc Production Master Control PCM 5.1 Metadata Video Emission Encode AC encode Proc Server Home Viewer OB Remote Production Proc Proc HD Routing With Embedded Audio and Meta Data AC-3 Home Receiver and Decoder PCM 5.1 Audio

47 1. Dynamic Loudness Meta Data The Theory DIALNORM -20 db Contribution Production Emission IRD IRD Proc Proc Proc Proc DIALNORM -21 db Production Server Master Control PCM 5.1 Metadata Video Emission Encode AC encode Home Viewer Audio Level will remain consistent OB Remote Production DIALNORM -27 db Proc Proc HD Routing With Embedded Audio and Meta Data DIALNORM changes as different sources aired AC-3 Home AC-3 Level Receiver and Dec Proc Decoder DIALNORM PCM 5.1 Audio

48 1. Dynamic Loudness Meta Data The Danger Device Modifies Processing Device Dumps Metadata Audio but does not adjust Contribution Production DIALNORM Emission IRD IRD DIALNORM -20 db But Wrong Proc DIALNORM value ProcMissing Proc Proc Production Server DIALNORM Value will be wrong Master Control PCM 5.1 Metadata Video Emission Encode AC encode Home Viewer Audio Level Will Be Wrong OB Remote Production Proc Proc DIALNORM HD Routing With Embedded Audio value Missing and Meta Data AC-3 Home AC-3 Level Receiver and Dec Proc Decoder PCM 5.1 Audio DIALNORM

49 Possible Problems with Dynamic DIALNORM Content Originator set DIALNORM Value wrong There is no DIALNORM Meta Data or it was dumped along the way A Processing step in the chain modified the audio level but did not modify the meta data Any one of these This situations happens could every cause single a radical day on level shift at the home as a result of a many simple DTV source channels change in master control

50 Conclusion: Option 1 Dynamic Meta Data This was the way the system was designed to function It is becoming technically feasible Currently few content providers are delivering consistent meta data The risks outweigh the benefits at this time

51 Loudness Management Strategies NEXT 1. Dynamic DIALNORM Meta Data (the Dolby Fantasy) 2. Establish Target Loudness, mix or preprocess all content to Target Loudness. 3. Process outgoing audio in real time to match Target Loudness

52 Establish Target Loudness, Mix or File Based Process all content to Target Loudness Establish a Target Playout Loudness Emission Level, Set For live content arriving from outside AC-3 Encoder to this Value specify Routing that Switcher content With be mixed to Embedded Standardized Audio and Target Meta Loudness Data IRD Monitor For pre-recorded content (ingested or MPEG Proc file based delivery), use a file based tool to process Masterthe audio to match Video to Encoder Server Standardized Control Target Loudness Proc AC-3 Audio Encoder Incoming and Production OB Remote Production Local Production Proc Proc For Live Local productions insist that show is File mixed Based to Standardized Target Loudness Delivery For Live Outside Production if possible insist that show is mixed to Standardized Target Loudness Fixed DIALNORM Value

53 File based processing concept File Based Loudness Processing Engine Un-processed File Watch Folder Server Processed File Ready Folder

54 How Is Filed Based Processing Different Instantaneous Loudness Average Loudness for Entire File Adjusted Content Target Loudness Processor lifts entire file by same amount 1. Processor has access to file from end to end and is able to establish average loudness for entire file 2. Processor makes a single processing adjustment that is applied to the entire file

55 How Is Filed Based Processing Different Dynamic Range Not Altered Processor lifts entire file by same amount Benefits of this approach The entire content is consistently processed, there is no pumping The dynamic range of the content is not altered

56 Examples of File Based Processing Dolby DP-600 Reads files from watch folders and scans entire file measuring loudness Option of only changing meta data only or of processing audio and replacing audio file Processing can be level shift only or compression Telestream Flip Factory Performs measurement and processing as part of normal format conversion process Processing can be level shift only or compression Benefit is that it does not represent extra step in the workflow

57 Establish Target Loudness, Mix or File Based Process all content to Target Loudness Incoming and Production Playout Emission Target??? IRD Monitor Routing Switcher With Embedded Audio and Meta Data Proc Proc Server Target Master Control ALC MPEG Video Encoder AC-3 Audio Encoder Local Target Production OB Proc Remote Production Target? Proc File Based Delivery Fixed DIALNORM Value= TARGET

58 File Based Loudness Processing Pros and Cons Pros: Content is adjusted to Target Loudness without undesired pumping effects or effects on dynamic range Perfect for commercials, promos and other pre-produced content that are produced out of house and typically are out of loudness specifications Filed based processing can be automated and integrated into existing file ingest, QC or transcode workflows Cons: Technique does not apply incoming content that is either live or being played back by a third party

59 Loudness Management Strategies NEXT 1. Dynamic DIALNORM Meta Data (the Dolby Fantasy) 2. Establish Target Loudness, mix or preprocess all content to Target Loudness. 3. Process outgoing audio in real time to match Target Loudness

60 ALC Process content in realtime prior to Plant Router Real-time Correction By processor Incoming and Production Playout Emission Target??? IRD Monitor ALC Routing Switcher With Embedded Audio and Meta Data Ingest Target Server Master Control MPEG Video Encoder AC-3 Audio Encoder Local Target Production OB Proc Remote ALC Production Target? File Based Delivery Target??? Software Loudness Correction tool Fixed DIALNORM Value= TARGET

61 Establish Target Loudness & process content in realtime Incoming and Production Target??? IRD Monitor Routing Switcher With Embedded Audio and Meta Data Playout Real-time Correction By processor Emission Proc Proc Server Target Master Control ALC MPEG Video Encoder AC-3 Audio Encoder Local Target Production OB Proc Remote Production Target? Proc File Based Delivery Fixed DIALNORM Value= TARGET

62 Option 3: Process content on the fly to match target Loudness Master Control Process the Audio so that it matches At Miranda We are Calling This ALC Target Loudness Level for Automatic Loudness Control (Call it Loudness AGC) Audio Level Processor Emission MPEG Video Encoder AC-3 Audio Encoder Loudness Measurment Fixed DIALNORM Value Establish a Target Loudness Level

63 The Challenge Multiple Segments Promo is Louder Long Form (Program) Segment N Short Form (Commercial / Promo) Segment N+1 Long Form Program Segment N+2

64 Constant Loudness Processor Audio with Varialble Loudness Compressor/ Expander/ Limiter Meta Data MUX Audio Fits Target Loudness Loudness Measurement Actual Control Target Target Loudness Level

65 Constant Loudness Processor Aims to Align Loudness Instantaneous Loudness Program Segment N (long form) Program Segment N+1 Promo/Commercial Target Loudness Loudness Processor Aims to Adjust Content to match Target Loudness

66 How A Loudness Processor Works XVP 3901 Universal Audio/Video Processor Video with embedded audio Demux Video Processing Audio Processing Mux Video with embedded processed audio Automatic Loudness Control Option Dynamic Compressor/ Expander/ Limiter Control Processor Processor Processor Preset 1 Preset 1 Preset 1 Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

67 How A Loudness Processor Works Video with embedded audio ITU-1770 or LEQA Loudness Measurement Automatic Loudness Control Option XVP 3901 Universal Audio/Video Processor Demux Video Processing Audio Processing Dynamic Compressor/ Expander/ Limiter Control Mux Processor Processor Processor Preset 1 Preset 1 Preset 1 Video with embedded processed audio Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

68 How A Loudness Processor Works Video with embedded audio Intelligent Control Compares Actual Loudness to Target Automatic Loudness Loudness Control Option XVP 3901 Universal Audio/Video Processor Demux Video Processing Audio Processing Dynamic Compressor/ Expander/ Limiter Control Mux Processor Processor Processor Preset 1 Preset 1 Preset 1 Video with embedded processed audio Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

69 How A Loudness Processor Works XVP 3901 Universal Audio/Video Processor Video Dynamic with To do a Processor Good Job embedded processing Will Adjust needs Levels to be Demux Video Processing audio on more The sophisticated fly based on than just control Gain Control Audio Processing Mux Video with embedded processed audio Automatic Loudness Control Option Dynamic Compressor/ Expander/ Limiter Control Processor Processor Processor Preset 1 Preset 1 Preset 1 Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

70 Automatic Loudness Control Fixes The Intra Segment Loudness Problem FINE PRINT Side effects may include pumping of audio and reduction in dynamic range which may not make the person who created good programs very happy Side effects may include pumping of audio and reduction in dynamic range which may not make the person who created good programs very happy

71 Automatic Loudness Control Processor Option Video with embedded audio XVP 3901 Universal Audio/Video Processor Card Stores Multiple Processor Presets that Demux Video Processing configure our processing Mux will react to changes in loudness Audio Processing Video with embedded processed audio Automatic Loudness Control Option Dynamic Compressor/ Expander/ Limiter Control Processor Processor Processor Preset 1 Preset 1 Preset 1 Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

72 Automatic Loudness Control Processor Option Video with embedded audio XVP 3901 Universal Audio/Video Processor Presets can be switched frame accurately by automation via GPI or Video with Demux Video Processing RS-422 Mux Port embedded processed audio Audio Processing Automatic Loudness Control Option Dynamic Compressor/ Expander/ Limiter Control Processor Processor Processor Preset 1 Preset 1 Preset 1 Automation and / or Control System Loudness Measurement Actual Target Target Loudness Level

73 Segment-Aware Preset Switching is key to avoiding undesirable effects of Automatic Loudness Control

74 The Challenge Multiple Segments Light or Disabled Processing Known Good Content Full, Fast Acting Processing Unknown / Uncontrolled Content Light or Disabled Processing Known Good Content Content Not Changed Content Not Changed Long Form (Program) Segment N Short Form (Commercial / Promo) Segment N+1 Long Form Program Segment N+2

75 Realtime Loudness Correction controlled by Automation Incoming and Production Target??? IRD Monitor Routing Switcher With Embedded Audio and Meta Data Playout Loudness Correction Controlled By Automation Emission Proc Proc Server Target Master Control ALC MPEG Video Encoder AC-3 Audio Encoder Local Target Production OB Proc Remote Production Target? Proc File Based Delivery Software Loudness Correction tool Automation

76 Summary of Loudness Management Strategies Regardless of the selected solution, make sure that the average loudness measured of the content is done using BS1770 and that the Dialnorm setting of your AC-3 encoder matches the value.

77 Part 3B: LOUDNESS MANAGEMENT STRATEGIES For Cable and TELCO

78 1000 Foot View of Solution Monitoring and Control System Incoming Signal Reception And Decryption Loudness Detection and Correction Transcoding, Muxing and Encryption

79 Decoding content to baseband: Using originators Loudness & dialnorm Avg. Loudness: -24 db and Consistent DIALNORM = -24 dbfs Fixed Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed Loudness & Dialnorm Follow originators value Avg. Loudness: -20 db and Consistent DIALNORM: -24 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System Decode Switch Loudness Measure Re-Encode IPTV or Cable System Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment Avg. Loudness: Varies by Segment DIALNORM: -24 db Fixed Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

80 Decoding content to baseband: Using Operators Loudness & dialnorm Avg. Loudness: -23 db and Consistent DIALNORM = -23 dbfs Fixed Avg. Loudness: -27 db and Consistent DIALNORM: -27 db Fixed Loudness Set by Operator Ex: -24LKFS Avg. Loudness: -20 db and Consistent DIALNORM: -20 db Fixed Avg. Loudness: -27dB and Consistent DIALNORM: -27 db Fixed IPTV or Cable System Decode Switch Loudness / Measure & Correct Re-Encode IPTV or Cable System Avg. Loudness: Varies by Segment DIALNORM: Varies by Segment Avg.Loudness: Varies by Segment DIALNORM: -24 db Fixed Local Ad Insertion Avg. Loudness -24 db DIALNORM: -24 db Fixed

81 Part 4: Available tools for Loudness

82 Loudness Meters CRC DK

83 Loudness meters Stand Alone Devices Cards (conversion modules) Multi-Viewers Dolby LM-100 Loudness: Target: Dialnorm: -23 db -27 db -24 db

84 File Base Loudness correction solutions Dolby DP-600 QuiC Media Analysis Server

85 Realtime Processors Aeromax TM Level Magic TM And many more.

86 Comparing the Three Processor Options Stand Alone Aeromax TM Multi-Band Conversion Modules Master Control (Miranda) Level Magic TM Wide Band Stand Alone Conversion Modules In House Loudness Control Solution Wide Band Multi-Zone Conversion Modules Master Control (Miranda)

87 Consummer tools Home Receivers Set top boxes

88 Consummer tools