NUGEN Audio VisLM User guide

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VisLM Operation Manual

OPERATION MANUAL

VisLM

Standardised Loudness Metering Solution

www.nugenaudio.com

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VisLM Operation Manual

Contents

Introduction

Interface

General Layout

Loudness Meter

Loudness History & Distribution

True Peak Meter

Options Panels

Preset Recall

Meters

Display

Alerts

Export (Text and Automation logs)

Global

Loudness History Mode

System

Elapsed

Time-code (Loudness Overdub mode)

Navigating Flags

Stand Alone Application

Loudness Metering in Practice

Reporting a Problem

Version History

www.nugenaudio.com

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Introduction

The NUGEN Audio VisLM is a loudness metering system fully compliant with the ITU-R BS.1770/1771 metering standard, EBU R128, ATSC A/85 and several other

region specic loudness standards.

VisLM is available in two versions, VisLM-C (compact) and VisLM-H (history). The operation of both versions is broadly the same, although VisLM-H has a number of additional features.

Both versions of VisLM are available in stereo, 5.1, 7.1 and 7.1.2 formats. Many plug-in hosts will now accept the surround version on any audio channel, however some

require channel specic implementation, so the 2.0 version is supplied for standard

stereo operation in these situations. The surround version will work correctly with track

counts from 1.0 up to 7.1.2 in hosts that provide this exibility.

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Interface - General Layout

The interface is designed to facilitate intuitive operation by grouping similar aspects

of operation into distinct zones as shown below. VisLM is highly congurable, with

the ability to show/hide many functions and parameters. This manual is illustrated using VisLM-H, and in general will show an expanded interface to allow explanation of all parameters.

1 Main display. The main display area shows the information relevant to the

current view setting; the Loudness Meter, True-Peak meter or Options page.

2 Main display control. These controls determine what is shown in the main

display. i) Loudness - Loudness Meter ii) True-Peak - True-Peak Meter iii) Options - Options panel

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3 Loudness history (VisLM-H only). The history view presents the historical

loudness and true-peak clip values over time.

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4 Loudness distribution (VisLM-H only). This optional view represents the

distribution of loudness measurement within the Integrated loudness measurement.

5 Loudness history macro View (VisLM-H only). This optional view shows the

overall loudness history stored by the plug-in. This view can be used to rapidly

locate areas of specic interest in the main loudness history view.

6 Resize control (VisLM-H only). This control is used to resize the interface to a

suitable proportion and scale to suit the available screen space and best t with your workow.

7 Plug-in title. Click to open licensing/credits panel and a direct link to open the

plug-in manual (if installed).

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Interface - Loudness Meter

This section displays the primary Loudness Meter values and controls. The performance and values given in this section of the meter are in accordance with and

as dened by ITU-R BS.1770 and/or EBU R128.

1 Loudness meter select. This control switches the main display to show the

Loudness Meter and is mutually exclusive to the True-Peak and Options select controls. The ‘+’ button can be used to open a combined True-Peak and Loudness Meter summary view.

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2 Loudness bar meter. Shows the level of the current audio input in Loudness

Units (LU/LUFS) as dened by EBU R128 or ATSC A/85 (LK/LKFS). The meter

can show either Momentary (M) or Short-term (S) loudness as a bar meter, with the remaining value indicated by a white arrow marker. It is also possible

to congure a split meter, with M/S or S/M meters side-by-side. Clicking the LUFS/LKFS unit marker cycles through the options, or the meters required can be specied directly via the options panel (see below). Various colour splits can

also be established using the parameters available in the Loudness Meter options panel.

3 Momentary (M)/Short-term Loudness (S) Meter Max Value. This value shows

Maximum value of the momentary or short-term loudness meter (click the M or S

indicator to toggle between the two). Click the numeric value to reset.

max

This value is also reset when the integrated loudness measurement is reset.

4 Momentary (M) loudness. Optional display (see Options panel below). Displays

the short-term loudness value as dened by ITU-R BS. 1770. This value may also

be indicated by the momentary loudness bar meter or using the white arrow

marker next to it depending upon user conguration.

5 Short-term (S) loudness. Displays the short-term loudness value as dened by

ITU-R BS. 1770. This value may also be indicated by the momentary loudness bar meter or using the white arrow marker next to it depending upon user

conguration.

6 Integrated program loudness (I). This value displays integrated loudness as

described in ITU-R BS.1770 (or as specied by the dialog measurement if this is

active) and is controlled using the Integrated loudness functions [8].

7 Integrated program loudness with Dialog gating (ID). This value displays the

integrated loudness as described in ITU-R BS.1770 with dialog gating using the Dialog Detection algorithm from Dolby Laboratories.

8 Loudness range descriptor (LRA). This value quanties the variation in a

time-varying loudness measurement and is supplementary to the measure of overall loudness, that is, ‘integrated program loudness’.

9 Dialog Loudness Range descriptor (LRAD). This value quanties the variation

in loudness, much like the LRA reading, but is applied only to sections where dialog is detected.

10 Integrated loudness functions. This group of controls provides access to the

Integrated Loudness section of the meter. In some history modes these controls may alter slightly in functionality (see Loudness History modes below).

• Auto. Select to activate/de-activate transport activation of controls. This control is not available in the stand alone version of VisLM.

• Play control. Start/continue the measurement of integrated loudness and

LRA simultaneously.

• Pause control. Pause the measurement of integrated loudness and LRA

simultaneously.

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• X control. Resets all measures. May be operated whether the meter is

running or paused.

• Gate (where relevant). Displays when the gate is active. This is only valid when audio is playing.

11 Mode indicator. This indicator lights to indicate which mode the meter is

operating in. It is possible to set VisLM to work specically to ‘EBU Mode’, ITU-R BS. 1770, ATSC A/85 and others. It may also be useful to dene ‘transitional’

settings moving toward loudness recommendations. In these situations, where

the full denition of a particular standard is not adhered to, the mode indicator

will show ‘custom’.

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Interface - Loudness History & Distribution

This section of the meter is only available in VisLM-H. The loudness history section displays the historical data of the short-term loudness reading (compensated for screen resolution where required). This view is active at all times, irrespective of the main display control settings.

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1 Loudness history view selector tabs. These controls determine which data is

shown in the loudness history.

• Arrow control. The arrow control found at the bottom of the selector tabs is used to expand the tab selectors to reveal further options. Once the desired options have been chosen, the control can be used to minimise the tabs, leaving maximum space available for data presentation.

• Macro/M control. Start/continue the measurement of integrated

loudness and LRA simultaneously.

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• History/H control. Used to toggle the history display on/off (see below). This causes the plug-in interface to resize. Depending upon your NLE/DAW, the plug-in interface may need to be closed and re-opened in order to resize the plug-in container.

When the tabs are in expanded view (see Arrow Control above), additional options are available.

• Int. Toggles the Integrated Program loudness indicator on/off in the

history display.

• Int (D). Toggles the dialog-gated integrated loudness indicator on/off in the history display.

• TP. Toggles True-peak clip notications on/off on the history display and

history macro view. These are shown on both displays as red dots, indicating the point at which a True-peak clip was detected.

• M. Toggles the Momentary loudness trace on/off in the history display.

• S. Toggles the Short-term loudness trace on/off in the history display.

• Variance. Toggles the Variance envelope on/off in the history display. The

variance measure is a sub-value of the loudness range descriptor, and shows the measure of variation in the level over time.

• Dist/D control. Used to toggle the loudness distribution display on/off.

• Flags. Toggles display of both alert and manual ags.

• Alert. Toggles display of alert ags. These are automatically dropped

ags that are triggered by the alerts set up in the preferences. See

Options - Alerts for more details.

• Manual. Toggles display of manually dropped ags. These can be

created by clicking on the Flag button and removed by clicking on the Clear button. See Navigating Flags for more details.

2 Loudness history inspector view. This area displays the loudness history

traces as determined by the history view selector tabs (see above), compensated for screen resolution where required. The data scrolls building up the view over time. The data for all traces within the loudness history view is continuously calculated and stored irrespective of whether the trace is active or not.

The loudness history inspector view can be scrolled in time by click-dragging left/right.

3 Loudness history follow control. This control determines whether the loudness

history automatically scrolls, following real-time input, or shows a static view to allow historical inspection. Click to toggle the control on/off.

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4 Loudness history zoom. Determines the zoom level of the history view, from

10 secs to 24 hours. All data is available until the plug-in is re-set, so it is possible to choose different zoom levels at differing times without loosing data from the view.

5 Pre-roll. In order for adjusted sections to be included in the overall loudness

reading, the audio must be in-sync. When you make an adjustment, you must begin playing a few seconds before the edit. This value tells VisLM how far back you intend to go. Under normal circumstances, you should set this to 3 seconds, but if you have effects with a long tail, you may need to increase this value and play back from a correspondingly earlier time.

6 Time reference. VisLM-H has three modes of time referencing, each with

different capabilities and applications.

• System. Chose this option to select a system clock (HH:MM:SS)

reference. When system time is selected, the time scale will scroll along with the history inspector view to allow events to correlated with the system clock.

• Elapsed. Elapsed time records the loudness at the audio input, scrolling

the input to the left as it is received. If the loudness history inspector view

is scrolled to view a specic set of data, this will cause the loudness data

trace to remain static, and (counter intuitively) the time reference scale will begin to scroll ‘backwards’ as the data on view is effectively becoming constantly older in the static display.

• Time code. Time code* referencing is only available in the plug-in version

of VisLM-H. When the time code reference is selected, loudness data is stored against time-code position. This mode enables the loudness overdub mode (a part of the proprietary NUGEN Audio ReMEM

technology), the functionality of which is described in detail below.

7 Loudness macro overview. This view shows a macro overview of the loudness

history stored within the plug-in. The rectangular window shows the data currently represented in the history inspector and can be dragged left/right to

rapidly locate a specic region in the loudness inspector.

8 Loudness distribution view. The loudness distribution shows the distribution

of short-term loudness measurements within the integrated loudness calculation. As a result, the graph will only show data if the integrated loudness calculation is active (or paused). The unshaded regions at the extremes of the distribution represent the data that is not incorporated into the LRA calculation.

*Time Code referencing of audio data is dependent upon the support provided to the plug-in via the NLE or DAW host. In some hosts this support is not available or only restricted functionality is available.

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Interface - True-peak Meter

The true-peak meter displays true-peak values as dened in ITU-R BS.1770. VisLM is

available in stereo, 5.1, 7.1 and 7.1.2 formats, with the 5.1, 7.1 & 7.1.2 formats being able to handle input from mono through to 7.1.2 surround automatically where the plug-in host facilitates this.

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1 True-peak meter select. This control opens the true-peak meter in the main

display, and is mutually exclusive with the Loudness Meter control (Loudness). To return to using the Loudness Meter in the main display, use the Loudness control. The ‘+’ button can be used to open a combined True-Peak and Loudness Meter summary view.

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2 True-peak level meter. Shows true-peak audio levels on available input channels

from single (mono) input, through to 7.1.2 surround. A permanent peak hold bar marks the highest level achieved. Click the meter to reset.

3 True-peak overload indicator. True-peak overload indicator. This indicator will

activate if the true-peak level reaches the level set on the options page, and hold momentarily after the signal has fallen below this threshold so as to be clearly visible when activated.

4 Momentary (M)/Short-term Loudness (S) Meter Max Value. This value shows

Maximum value of the momentary or short-term loudness meter (click the M or S

indicator to toggle between the two.) Click the numeric value to reset.

max

This value is also reset when the integrated loudness measurement is reset.

5 TPmax. This value gives the maximum reading for the True-peak meter. Click

the value to reset.

6 Surround routing. This control determines the routing for multi-channel audio

up-to 5.1, 7.1 or 7.1.2.

It is important to choose the correct routing, as the Loudness Meter measurement weights individual channels differently.

5.1 routings available:

• DTS: L R Ls Rs C LFE

• ITU: L R C LFE Ls Rs

• Film: L C R Ls Rs LFE

7.1 routings available:

• DTS1: L C R Ls Rs Lr Rr LFE

• DTS2: L R C LFE Ls Rs Lr Rr

• Dolby1: L C R Ls Rs Lb Rb LFE

• Dolby2: L R C LFE Ls Rs Lb Rb

• SDDS1: L Lc C Rc R Ls Rs LFE

• SDDS2: L R C LFE Ls Rs Lc Rc

• NM: L R C LFE Lsr Rsr Ls Rs

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7.1.2 routings available:

• ProTools 7.1.2: L C R Ls Rs Lsr Rsr LFE Lts Rts

• LR 7.1.2: L R C LFE Ls Rs Lsr Rsr Lts Rts

• ProTools 5.1.4: L C R Ls Rs LFE T Tfr Trl Trr

• LR 5.1.4: L R C LFE Ls Rs T Tfr Trl Trr

• NM 7.1.2: L R C LFE Lsr Rsr Ls Rs Lts Rts

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Interface - Options Panels

The options panels allow for in-depth conguration of the various meter parameters. It is possible to congure the meter in a number of different ways to suit the intended

application.

To facilitate detailed conguration, the options available have been grouped into logical

tabs as detailed below.

1 Options select. This control opens the Options window in the main display, and

is mutually exclusive with the Loudness Meter control (Loudness) and True-peak meter control (True-peak). To return to using the meters in the main display, select the appropriate control or click the Options button again.

2 Presets recall. This control opens the preset browser window. The name of the

current preset is shown in the window along side. If the options are later changed from the default preset parameters a ‘*’ character will show next to the preset name.

3 Options tabs. The options tabs allow access to similarly groups functions to

enable rapid navigation to the desired parameter. Click a tab to switch to the associated functions.

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Options - Preset Recall

The preset recall button (see above) is available at the top of the options page,

irrespective of the chosen options tab and allows for rapid re-conguration of the

entire plug-in in keeping with the guidelines set out in many international and regional standards. It is also possible to set the default opening parameters for the plug-in

after detailed user conguration settings have been applied.

1 Preset list. The preset browser opens a list containing many of the international

loudness standards which allow immediate conguration of all VisLM settings.

There are also illustrative presets which demonstrate some of the more advanced settings available. To select a preset simply mouse-over the preset title in the list, which which will then be highlighted, and click to load the parameters. The preset will be loaded and the preset browser will close.

2 Next (previous). Click next (or previous) to move between pages of presets.

These controls only show if the window size of the plug-in is such that the entire list cannot be shown in one screen.

3 Set current as default. This option will set the current settings as the default

opening settings for all new instances of VisLM.

4 Close. Closes the preset browser if no further functions are required.

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Options - Meters

The meters tab contains detailed set-up options for both the loudness and True-peak meters.

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1 LM/ T P. These controls toggle the settings between the Loudness Meter (LM)

and the True-peak meter (TP). The conguration parameters are broadly similar,

with related parameters shown in the same position on both pages.

Mode. This setting denes the underlying mode of operation for the Loudness

Meter. Different standards and recommendations dene slightly differing

algorithms. The mode selector can be used to determine which the Loudness Meter uses to calculate the loudness value.

S-Window. This value is usually set to 3 seconds, as dened by most standards,

however there are recommendations which choose a different value, which can be set here if required.

Peak. Turns on the peak hold bars in the loudness bar meters.

Segments. Determines the number of loudness units represented by each

segment on the momentary/short-term loudness meter/s.

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2 Splits. This section allows the Loudness Meter and True-peak Meter (and meter

history – VisLM-H only) to be split into colour banding to facilitate the rapid

assessment of whether loudness readings are falling within specication.

The split values (1 to 4) determine the position of the colour boundaries. Click-drag up and down to change the value, or double-click to enter a value directly. To change the colours of the sections, click the swatch to open up the

colour picker window. Select LM to dene settings for the Loudness Meter, TP

for the True-peak Meter.

3 LM (TP) scale upper/lower. Denes the upper and lower boundaries of the

loudness meter scales. Depending upon the precise aspect ratio of the meter in

practice, the scale may show slightly more than dened there, these are the minimum specications required.

Offset. This value allows for absolute scale mapping (Full Scale) or mapping

of the zero point to some other value, such as target loudness (as in BS. 1771).

The EBU target loudness is dened as –23 LUFS = 0 LU, ATSC gives - 24 LKFS = 0 LK, although other values can be dened.

Display. Allows you to edit various elements of the display (see below).

Bar Meter. Determines what is shown by the loudness bar meter.

• M: Bar meter shows Momentary loudness

• S: Bar meter shows Short-term loudness

• M|S: Bar meter shows Momentary then Short-term loudness

• S|M: Bar meters shows Short-term then Momentary loudness

These options can also be cycled through by clicking the units display (LUFS/

LKFS) at the bottom of the bar meters in the loudness display.

4 LM/ T P. See above.

Ballistics. Sets meter ballistics to recognised standards. The update rate and

time window is as dened in EBU R128, this parameter determines the decay

time only.

TP clip. Sets the value at which the true-peak overload indicator lights.

Peak. Turns on the permanent peak hold bars in the loudness bar meters.

Temp peak. Determines the temporary peak-hold time (enter ‘0’ for Off).

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Options - Display

These settings allow you to change what is displayed. The check boxes will turn the various readings on and off. Note that readings will only display when there is enough room. When at its smallest size, VisLM has enough room to show three readings. If you wish to display more, you will need to make the window larger in order for them to be shown.

1 Gating. This is the gating that should be used for the integrated lozenge. You can

select one of three options: Ungated, G8 and G10.

2 Units. This has no effect on the reading, but changes the units displayed to be

LUFS, LKFS or dB.

3 Min Dialog %. If you are displaying the Integrated Dialog reading, then it will be

greyed out if the percentage of the program currently containing dialog is less than this percentage.

4 Min LRA time. If the amount of audio received is less than this amount, the

reading may be considered unstable and will be greyed out.

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Options - Alerts

Alerts can be set to give a visual warning if loudness parameters deviate from desired values for a given amount of time. This can be instantaneous if these are pass/fail

criteria, or set to alert after a specic time period if the warning is for guidance only.

Minimum and Maximum alert levels are set and activated independently for each parameter.

Each alert option can be set to On, Off or Auto. If an alert is off, it will not be triggered.

If it is on, it will be triggered when the level specied in the corresponding ‘Alert’ box is reached, but only if the level has passed the limit for longer than the duration specied

in the ‘Period’ box. The alert will remain active until the corresponding read-out is clicked, even if the level returns to an acceptable level. If the alert is set to auto, it behaves in a similar manner to when it is on, but it will be cleared as soon as the level is no longer past the limit.

An alert warning is indicated on the loudness meter interface numerical read-out. If a parameter exceeds the alert level, the read-out will change colour to orange text, to indicate an alert has been triggered. Click the loudness value to re-set the alert.

Note that only the enabled parameters will be available for adjustment. You can change which parameters are visible by clicking on the ‘Display’ button from the Meters tab.

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Options - Export

The export tab is used to determine what data (if any) is exported by the plug-in during

operation. VisLM can export loudness data to both a text le and as automation data

for display of loudness data in the timeline.

The Tex t l og control determines whether text logging is activated. The frequency of

data logging is specied as number of seconds between each entry using the Log Freq parameter. The le name and path are determined using the text log box. The radio

buttons can be used to activate/de-activate data export, and select the values to be

included in the le.

Multiple instances of VisLM will export to unique data les. The data is exported as a csv (Comma Separated Value) le, and as such can be readily imported in to common

spreadsheet programs for graphing and further analysis.

The Auto Log controls toggles on/off the automation logging feature. When active, a series of automation parameters will be generated at the set interval Log Freq.

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Options - Global

The global tab contains parameters affecting the entire plug-in globally.

Zoom Level. When the plug-in is resized (VisLM-H only), it is possible to resize the

text. Depending upon the reason for resizing this may or may not be desirable. Auto, automatically scales the text depending upon the size and aspect ratio. Regular chooses the standard font size and Large forces the interface to large text view.

TC Offset. If the NLE time-line is offset from zero, this parameter can be used to offset

VisLM-H so that time-code positions match the NLE.

Frame Rate. If frame-rate notication is not passed to the plug-in via the NLE, this

parameter can be used to ensure sync is properly locked.

Save History. If you are editing a large program, the history data can take a

considerable amount of space and may cause issues if your DAW/NLE attempts to auto-save whilst playing audio. You can use this option to disable the saving of the history data (all other settings and options will still be saved), then when you have

nished editing you can turn this option back on to save your work.

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Loudness History Mode (VisLM-H Only)

VisLM-H is capable of recording and displaying the loudness history over time Depending upon the mode selected, this can be used to investigate the evolution of loudness parameters, exclude time periods from the Integrated Program calculation and even overdub discreet audio sections, allowing re-calculation of loudness values without the need to re-play the entire program through the meter.

This section discusses the different history modes and the differing functionality available within each mode.

VisLM-H offers three history modes:

• System - Loudness data is logged against real-time system clock information

• Elapsed - Loudness data is logged relative to the ‘start’ of data input

• Time Code - Loudness data is logged against Sample/time code reference

In all three modes, the loudness data for each reading is stored irrespective of whether the particular graph view is active, and can be toggled on/off at any time for inspection. The loudness data is saved with the session and will be recalled when the session is re-opened.

In general the operation for each mode is the same. The data is stored over time from left to right, with the screen automatically scrolling as new data is acquired when the loudness history follow control is active (see Interface - Loudness History for detail about the individual controls).

The time span the history view shows can be increased or decreased using the History Zoom control and the data can be scrolled in the time-line by clicking and dragging left and right.

The History Macro view gives an overview of all the data stored, with the rectangular white box indicating the data currently under inspection in the main window. The

rectangular box can be dragged left and right to rapidly locate a specic time window

in the main history view.

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Loudness History Mode - System

The System Time reference logs loudness data against the time as measured by the System Clock of the host machine for up to 24 hours. System time is useful for realtime monitoring of live audio feeds.

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1 2 5

1 System Time Indicator. Click to select ‘System’ from the pop-up box to activate

System time mode.

2 System Time Scale. In System mode, the loudness history shows the loudness

values against a scale indicating the hh:mm:ss that the data was received.

As the system time is an absolute, not a relative value, it is not possible to overdub loudness values in this mode, new data is always recorded and logged at the relevant system time value in the time line.

3 Transport controls. In system time, the transport controls can be used to

determine how the data is stored and which data is included in the Integrated Program Loudness and LRA calculation.

The ‘X’ button clears all data, ushing the memory and resetting all loudness

parameters.

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The ‘Auto’ button automatically activates the ‘X’ button, resetting all loudness parameters with the transport control. This can be useful when recording and measuring loudness of discreet audio sections one after the other.

The ‘Play’ arrow control begins Integrated Program measurement.

The ‘Pause’ control temporarily pauses the Integrated Program measurement and LRA, whilst retaining all data up until that point. Measurement can be restarted by clicking the control again. This feature is useful if for instance, a commercial break inserted into a program is to be excluded from the loudness calculation.

4 When the Integrated Program Loudness and LRA calculation is paused, the

data that is exuded from the measurement is shown ‘grey’ in the loudness history and macro view. The individual Short-term and Momentary loudness traces are still shown, but this data is excluded from the overall Integrated Program Loudness calculation.

5 History Follow control. When the history has been scrolled in the main window,

the follow control is automatically de-activated. This allows the history window to show the data without scrolling to update to the more recent input. This data is continuously generated whether the view is following the current input or not. To automatically scroll and follow the input, re-activate the control.

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Loudness History Mode - Elapsed

The Elapsed time reference operates in a similar manner to the System mode except that the incoming loudness data is logged only when it is received, thus the audio loudness as measured over the last hh:mm:ss is shown. This mode is useful when moving around the time-line, playing in numerous sections to measure an over-all Integrated Program Loudness value. It can also be used as a simple alternative to other modes, when measuring sections of audio, using the Auto control to reset the measurement automatically.

1 2 5

1 Elapsed Time Indicator. Click to select ‘Elapsed’ from the pop-up box to

activate Elapsed time mode.

2 Elapsed Time Scale. In Elapsed mode, the loudness history shows the loudness

values against a scale indicating the hh:mm:ss since the data was received.

It is not possible to overdub loudness values in this mode, new data is always appended and logged subsequent to measurements previously taken.

3 Transport controls. In elapsed time, the transport controls can be used to

determine how the data is stored and which data is included in the Integrated Program Loudness and LRA calculation.

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The ‘X’ button clears all data, ushing the memory and resetting all loudness

parameters, beginning a fresh set of data.

The ‘Play’ arrow control begins Integrated Program measurement.

4 When the Integrated Program Loudness and LRA calculation is paused, the

data that is excluded from the measurement is shown ‘grey’ in the loudness history and macro view. The individual Short-term and Momentary loudness traces are still shown, but this data is excluded from the overall Integrated Program Loudness calculation.

5 History Follow control. When the history has been scrolled in the main window,

the follow control is automatically de-activated. This allows the history window to show the data without scrolling to update to the more recent input. This data is continuously generated whenever input is received, whether the view is following the current input or not. To automatically scroll and follow the input, re-activate the control.

Note. If the history view has been scrolled to show data recorded in the past, and new data is still being received, the time-scale will appear to scroll ‘backwards’. Because new data is still being added to the time-line, this is in fact correctly

representing the data, even if it may seem counter intuitive at rst. The data in

view, is now falling further and further into the past as new data is added and the time elapsed since it’s recording is increasing.

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Loudness History Mode - Time Code

The Time Code reference is only available in the Plug-in version of VisLM-H and then only when the DAW/NLE supports time-code referenced audio data in it’s plug-in architecture.

In Time-code mode, loudness measurements are logged by the plug-in with Time Code referencing. This means that the plug-in knows precisely where the data belongs in the time-line and enables the ability to overdub small sections of audio that have changed in the loudness history to immediately re-calculate the overall Integrated Program Loudness without having to re-measure all of the audio again.

4 5

1 5 2 6

1 Time Code Indicator. Click to select ‘Time Code’ from the pop-up box to

activate Time Code mode.

2 Time Code Scale. In Time Code mode, the loudness history shows the loudness

values against a scale indicating the time code hh:mm:ss that the data was received.

As all time-code position data refers to a unique point in the time line, it is possible to overdub loudness values in this mode. If new data is received for a time-code position it will be written to that position, allowing overdubs of new audio data to be made after an edit. All remaining data is retained, and so a new Integrated Loudness and LRA calculation will be produced after the overdub.

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3 Transport controls. In Time Code mode, the transport control behaviour is

slightly different to other modes.

The ‘X’ button clears all data, ushing the memory and resetting all loudness

parameters.

The ‘Play’ arrow control begins Integrated Program measurement. In Time Code mode this control is always active, as all the data received forms part of the measurement.

The ‘Pause’ is not available in Time-code mode. All loudness data generated is

included in the Integrated Program Loudness and LRA calculation. If a specic

set of data is not to be included, then simply avoid playing this section of audio into the plug-in.

4 As loudness is measured, the loudness prole is built up in the history view. In

Time code mode it is possible to move the transport in the time line and play audio from any position. The audio is measured in the correct Time Code position in the history view.

Any sections of the time-line where audio has not been received are highlighted in grey, showing that the plug-in has yet to receive data for this region.

5 Overdub Pre-roll. If audio has previously been received for a section of Time

Code, VisLM-H will perform a loudness overdub when new audio is played ie. after an edit.

In order to correctly update all the loudness information during an overdub, VisLM-H needs to ‘tie-in’ the audio either side of the over-dub for a default of 3 seconds (the Short-term loudness calculation uses a short-term sliding window of 3 seconds in order to determine a value). The simplest way to automate this is to set the pre-roll functionality of the NLE/DAW to 3 seconds, so that any edit position automatically plays in this ‘tie-in’ section.

If an audio overdub begins without the initial tie-in, this will be highlighted by a pink region as shown and an earlier play position will need to be chosen to generate the tie-in data.

Once the audio is locked to a recognised set of loudness measurements, the overdub data will be written, overwriting previous loudness measurements. When the end of the overdub is reached, VisLM-H will then seek to tie-in the end

of the section with 3 seconds of recognised readings. Once this has nished,

the overall Integrated Program Loudness will be shown for the entire data-set.

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Note: Some NLE/DAW hosts also rapidly fade in audio at play re-start. This

functionality should either be disabled or set to a minimum. It is also worth noting that many FX plug-ins require a ‘lead time’ to reach a stable reference position eg. Delay and reverbs are echoing audio previously received. In this case a longer pre-roll may be required. It is also possible that a plug-in will not in fact reproduce audio in the same way each time ie. There is a random element

involved. In this case, an over-dub would not be possible without rst rendering

the plug-in in order to give the same loudness reference for each pass.

6 History Follow control. When the history has been scrolled in the main window,

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Navigating Flags

Whilst processing audio, VisLM can be congured to mark periods where the loudness

readings stray outside of expected boundaries. These can be displayed on the history

interface, along with manually dropped ‘ags’ and appear in either red or orange.

1 2 3 4 5 6

Orange ags are those that have been dropped manually. Red ags are positions where an alert has been triggered. Note that alert ags appear where the alert is rst activated. The navigation buttons at the bottom allow you to quickly move between ags.

1 Move to the rst visible ag 2 Move to the previous ag 3 Mark the current playback position with a manual ag 4 Clear all manual ags 5 Move to the next ag 6 Move to the last ag

If the current ag is an alert, an extra window appears in the bottom-right corner of the

history showing you the time at which the alert occurred and the readings at that point. Readings that are in the alert state will be highlighted in red.

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Stand Alone Application

VisLM is also available as a stand-alone application for Win/OSX in addition to the plug-in versions.

The stand-alone application is designed to monitor the ASIO Audio Input/s of the machine it is installed on, turning it into a free-standing, independent loudness meter.

Note: Within Windows and OSX, there is no option to route the Audio Output

directly into a secondary application, the VisLM application can only monitor the Audio Input. 3rd Party products are available to add this functionality if required.

The functionality of the VisLM application is exactly as that of the plug-in with the addition of a number of menu items.

File: Load settings…

Save Settings Save Settings as… Quit

Settings: Change audio device settings Select the device for audio input

Show channel routing matrix Allows for detailed input cong

Open on system start-up Opens VisLM-H on start

About: Opens credits, licensing and de-authorisation window.

Calibration and test tones

Whilst VisLM needs no specic calibration or set-up when used with-in a DAW, in

situations where external audio paths are used to transfer audio to the host machine, it can be useful to check that the signal path is transmitting the data without accidental

ltering or attenuation (using a digital connection is recommended to reduce/eliminate

these potential complications).

Both the ITU and EBU provide test tone specications for checking meter compliance, calibration and set-up and these are listed below.

ITU-R BS. 1770/1 Test Tone

If a 0 dB FS 1 kHz sine wave is input to the left, centre, or right channel input, the indicated loudness will equal –3.01 LKFS

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ITU-R BS. 1770/1 Test Tone

Test Signal Expected response (and tolerance)

1 Stereo sine wave, 1000 Hz, -23.0 dBFS (per-channel peak

level); signal applied in phase to both channels simultaneous; 20s duration

2 As #1 at -33.0 dBFS M, S, I = -33.0 ±0.1

3 As #1, preceded by 20 s of -40 dBFS stereo sine wave, and

followed by 20s of - 40 dBFS stereo sine wave

4 As #3, preceded by 20 s of -75 dBFS stereo sine wave, and

followed by 20 s of - 75 dBFS stereo sine wave

5 As #3, but with the levels of the 3 tones at -26 dBFS, -20

dBFS and -26 dBFS, respectively

6 5.0 channel sine wave, 1000 Hz, 20s duration, with per-chan-

nel peak levels as follows: -28.0 dBFS in L and R -24.0 dBFS in C -30.0 dBFS in Ls and Rs

M, S, I = -23.0 ±0.1 LUFS M, S, I = 0.0 ±0.1 LU

LUFS M, S, I = -10.0 ±0.1 LU

I = -23.0 ±0.1 LUFS I = 0.0 ±0.1 LU

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Loudness Metering in Practice

VisLM provides Loudness Metering to several dened standards, and can be tailored to suit many specic situations using the many options available.

A good starting point is to select a Preset using the preset selections available via the

options page. The preset will select an algorithm that meets the specication of the

recommendations of the standard referred to in the title. This will set up VisLM to give readings that can be used to meet the production requirements of the standard selected. A description of some of these settings is given below.

Preset Description

ATSC A/85 LKFS Full scale loudness meter to 0 LKFS

ATSC A/85 LK Relative scale loudness meter off-set to 0 = -24 LKFS

EBU R128 LUFS +9 Full scale loudness ‘EBU Mode’ meter to 0 LUFS

EBU R128 LUFS +18 Full scale loudness ‘EBU Mode’ meter to 0 LUFS

EBU R128 LU +9 Relative scale loudness meter off-set to 0 = -23 LUFS

EBU R128 LU +18 Relative scale loudness meter off-set to 0 = -23 LUFS

AGCOM 219/9/CSP LUFS Full scale loudness meter to 0 LUFS

AGCOM 219/9/CSP LU Relative scale loudness meter off-set to 0 = -24 LUFS

ITU-R B.S. 1770/1 LKFS Full scale loudness meter to 0 LKFS

ITU-R B.S. 1770-2 LKFS Full scale loudness

ITU-R B.S. 1864 LK Relative scale loudness meter off-set to 0 = -24 LK

ARIB TR-B32 Full scale loudness

Gated algorithm (G10) ITU-R B.S. True Peak Metering Over at –2dBTP

Gated algorithm (G10) EBU +9 Scale True Peak Metering Over at –1dBTP

Gated algorithm (G10) EBU +18 Scale True Peak Metering Over at –1dBTP

Gated algorithm (G10) EBU +9 Scale True Peak Metering Over at –1dBTP

Gated algorithm (G10) EBU +18 Scale True Peak Metering Over at –1dBTP

Gated algorithm (G8) ITU-R B.S. True Peak Metering Over at –2dBTP

Gated algorithm (G8) True Peak Metering Over at –2dBTP

Un-gated algorithm ITU-R B.S. 1771 Scale True Peak Metering Over at –2dBTP

Gated algorithm (G10) ITU-R B.S. 1771 Scale True Peak Metering Over at –2dBTP

Un-gated algorithm ITU-R B.S. 1771 Scale True Peak Metering Over at –2dBTP

Gated algorithm (G10) ITU-R B.S. 1771 Scale True Peak Metering Over at –1dBTP

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Taking Measurements and meeting loudness requirements.

The loudness requirements for different companies and institutions vary, so the guidelines below are supplied as background reading and to introduce the principles involved.

Choosing the underlying loudness standard.

VisLM is capable of meeting several loudness standards. All these standards are based

on the denition of loudness measurement as dened in ITU-R B.S. 1770. Using this

standard measurement of other recommendations such as EBU-R 128 and ATSC A/85 have been produced. Before making loudness measurements with the intention of

meeting loudness delivery specications it is important to choose the correct standard.

Many of these are included as presets, others can be established using the parameters on the options page.

For more general loudness investigations, where no specic mode of operation is dened, any of the standard presets will give useful results.

Momentary Loudness.

This value is a rapid changing measure of the loudness at a point in time. It is generally used to aid mixing by ear and for spotting brief peaks and troughs that might otherwise go undetected. As the value changes rapidly, it is represented using the bar meter to facilitate easy reading. The maximum value reached Mmax is also indicated. This can be reset by clicking the readout.

Momentary Loudness can be specied for short-form loudness measurements, where the LRA reading is not appropriate. It is not usual for Momentary and Short-term

loudness maxima to be specied simultaneously.

Short-term Loudness.

Short-term loudness is a measure of the loudness over a longer time period than the momentary value and is a good measure of how the loudness of the audio is perceived over time. By default, the loudness history display (VisLM-H) displays the historical value of short-term loudness.

Preferred Short-term Loudness ranges are often (although not always) detailed within in

loudness requirement delivery specications. Eg. Short-term Loudness values within -32 and -22 LKFS are preferred, or Short-term Loudness values are not to exceed -20 LKFS. Using the colour splits and/or the alerts settings, VisLM can be congured to show

these ranges clearly so that any deviation beyond is easily picked up (see Fig. 1 & 2)

Momentary Loudness may also be specied for short-form loudness measurements,

where the LRA reading is not appropriate. It is not usual for Momentary and Shortterm

loudness maxima to be specied simultaneously.

Integrated Loudness.

Integrated Loudness is a single value of loudness that denes the ‘average loudness’

of an entire section of audio. This value is used for the purposes of loudness

normalisation, allowing sequential sections of audio to be matched, ensuring loudness consistency throughout station programming.

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The Integrated Loudness for a program or section is measured either by measuring

the entire section of audio, or in some specications, by measuring a carefully

selected ‘anchor’ section.

The integrated loudness value is usually given in loudness requirement delivery

specications. A single value is given eg. The programme material shall have an

integrated loudness value of –23.0 LUFS.

Again, using the colour splits, VisLM can be congured to show the target loudness

clearly so that the audio spread around this value can be seen easily (see Fig. 1 & 2)

A note on Leq

measurement and TASA submission.

VisLM measures Leqm to one decimal place. However, when making a submission to TASA specications the rounded up whole number value is required.

eg. If VisLM shows a value of Leq submission would be Leq

85.

84.3, the TASA specication value noted at

Loudness Range (LRA).

Loudness Range is a measure of the variation of loudness measurement of a section of audio, and is measured along side the Integrated Loudness value. The LRA value can be used in helping to determine whether dynamic treatment of the audio is required.

Note:

The LRA measurement is very sensitive when used to measure very short sections of audio.

“It is noted that measurement of very short programmes, where leading or trailing silence is included, or of programmes consisting, for example, of isolated utterances, could result in misleadingly high values of LRA.” EBU tech doc 3342, section 3.1

To measure LRA consistently, the following should be taken into consideration:

1 Begin measurement away from the ‘start’ point of the DAW sequence. This is

because some DAW’s rapidly ramp up the level of the audio in order to avoid

clicks when starting audio in the middle of a le.

2 The measurement should be paused immediately after the audio clip has ended

to avoid the following silence being taken into account.

Variance.

The Variance envelope shown in the loudness history section of VisLM-H is a subvalue of the loudness range descriptor, and shows the measure of variation in the Short-term loudness over time.

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Fig 1. VisLM-H showing a preferred ‘green zone’ Short-term Loudness range,

with a target loudness of –24 LKFS dened by a change in shading.

Fig 2. VisLM-H showing a ‘green zone’ Short-term Loudness range,

with a no-go zone highlighted in red.

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Reporting a Problem

If you encounter a problem with any of NUGEN Audio’s products, please let us know, to help us improve them.

Please email NUGEN Audio at [email protected] giving a clear explanation of the problem. Please state how frequently you’ve experienced the problem. If there are any particular steps you need to go through to see the problem, please detail these.

Please also state your operating system, and the rough specs for your machine (e.g.- CPU speed, RAM) - in Windows XP you can get this information by rightclicking “My Computer” and selecting properties.

Please be patient with any problems you may experience, particularly with products at a beta stage of release. At NUGEN Audio we take problems with our software seriously, and will endeavour to correct them as quickly as possible.

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Version History

2.0.1 Initial release

2.1.0 Added Leq(m) support Added support for HDX kits

2.5.0 Added Leq(a) support Added ITU-R B.S. 1770-4 support

2.5.2 Improved performance Improved HDX support (reduced processor power required)

2.7.0 Added dialog presets for 7.1

Added support for new EBU LRA specication

Updated TP splits in various presets

2.8.0 Added support for Dialog LRA

Improved readout congurability

Added 7.1.2 support Added SAWA support

Included Netix preset

Improved performance

Improved Dialog measurement for surround congurations

2.8.1 Added support for channel counts other than 2, 6, 8 and 10

2.8.2 Sped up Audiosuite processing Fixed Automation logging Fixed TP Clip level alerts Fixed history saving/loading

2.8.3 Updated Netix preset Added ag navigation

Fixed sync issues in Ableton

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