MANAGEMENT OF BROADCAST AUDIO LOUDNESS

• US 20170302241A1
• Filed: 06/29/2017
• Published: 10/19/2017
• Est. Priority Date: 11/13/2012
• Status: Active Grant

• Current Assignee: Grass Valley USA Incorporated
• Original Assignee: Snell Limited (Belden Inc.)
• Inventors: Knee, Michael James
• Granted Patent: US 10,027,303 B2
• Time in Patent Office: Days
• CPC Class Codes: H03G 3/3005 in amplifiers suitable for low-frequencies, e.g. audio amplifiers H03G3/32, H03G3/34 take precedence
• CPC Class Codes: H03G 3/32 the control being dependent upon ambient noise level or sound level
• CPC Class Codes: H03G 3/341 Muting when no signals or only weak signals are present H03G3/344, H03G3/345 take precedence
• CPC Class Codes: H03G 3/348 Muting in response to a mechanical action or to power supply variations, e.g. during tuning; Click removal circuits
• CPC Class Codes: H03G 9/005 of digital or coded signals
• CPC Class Codes: H03G 9/025 frequency-dependent volume compression or expansion, e.g. multiple-band systems H03G9/10, H03G9/18 take precedence

Abstract

To control loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, representative loudness values for content respectively before (P) and after (C) the junction are received from a playout automation system. A time-varying gain control is applied before and after the junction in order to smooth loudness around the junction. The audio gain is smoothly increased prior to the junction to a gain (P+C)/2P times higher than the original gain value. Then, the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value. After the junction, the gain is returned smoothly to the original value.

Claims

1. A method for controlling loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, the method comprising the steps in an audio processor of:

obtaining at said audio processor a first representative loudness value P before the junction;

obtaining at said audio processor a second representative loudness value C after the junction in which the second representative loudness value is received from a playout automation system; and

applying a time-varying gain control to the content using said audio processor in order to smooth its loudness value across the junction.

where the audio gain applied to the content has an original gain value; and

the audio gain applied to the content is smoothly increased prior to the junction to a gain (1+SA(C−

P)/P) times higher than the original gain value and is smoothly decreased after the junction from (1+S(1−

A)(P−

C)/C) times its original value

where A is a variable parameter between 0 and 1 representing the relative importance of preserving the loudness before and after the junction

S is a variable parameter greater than 0 and less than or equal to 1 representing the relative importance of smoothing loudness values and preserving original loudness values.

2. A method according to claim 1, in which the first representative loudness value P is measured over a predefined period before the junction.

3. A method according to claim 1, in which the first representative loudness value P is measured continuously to provide a rolling loudness value.

4. A method according to claim 1, in which the first representative loudness P value is received from a playout automation system.

5. A method according to claim 1, in which the time-varying gain control is applied to the content after the junction.

6. A non-transitory computer readable medium containing programming instructions for instruction for causing a programmable apparatus to implement a method for controlling loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, the method comprising the steps of:

obtaining at said audio processor a first representative loudness value P before the junction;

obtaining at said audio processor a second representative loudness value C after the junction in which the second representative loudness value is received from a playout automation system; and

applying a time-varying gain control to the content using said audio processor in order to smooth its loudness value across the junction.

where the audio gain applied to the content has an original gain value; and

the audio gain applied to the content is smoothly increased prior to the junction to a gain (1+SA(C−

P)/P) times higher than the original gain value and is smoothly decreased after the junction from (1+S(1−

A)(P−

C)/C) times its original value

where A is a variable parameter between 0 and 1 representing the relative importance of preserving the loudness before and after the junction

S is a variable parameter greater than 0 and less than or equal to 1 representing the relative importance of smoothing loudness values and preserving original loudness values.