Management of broadcast audio loudness
View Patent ↗To control loudness during a junction between different types of broadcast content, such as a junction between program 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.
1. A method for controlling loudness across a junction between different types of broadcast 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 audio gain to the content using said audio processor in order to smooth loudness across the junction where:
said audio gain has an original gain value; and
said audio gain 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 the original gain 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. The method according to claim 1 , in which the first representative loudness value P is measured over a predefined period before the junction.
3. The method according to claim 1 , in which the first representative loudness value P is measured continuously to provide a rolling loudness value.
4. The method according to claim 1 , in which the first representative loudness P value is received from a playout automation system.
5. A non-transitory computer readable medium containing programming instructions for instruction for causing a programmable apparatus to implement a method for controlling loudness across a junction between different types of broadcast 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 audio gain to the content using said audio processor in order to smooth loudness across the junction;
where:
said audio gain has an original gain value; and
said audio gain 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 the original gain value.