Management of broadcast audio loudness

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.

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.   
     
     
         2 . A method according to  claim 1 , in which:
 the audio gain applied to the content has an original gain value;   the first representative loudness measure P is compared with the second representative loudness measure C; and   when P<C the audio gain applied to the content is reduced shortly before the junction by the ratio P/C and is restored gradually to the original gain value after the junction.   
     
     
         3 . A method according to  claim 1 , in which the first representative loudness value P is measured over a predefined period before the junction. 
     
     
         4 . A method according to  claim 1 , in which the first representative loudness value P is measured continuously to provide a rolling loudness value. 
     
     
         5 . A method according to  claim 4  in which:
 the audio gain applied to the content has an original gain value; 
 an audio gain reduction that is proportional to said rolling loudness value is applied to the content shortly before the junction; and 
 the gain is subsequently smoothly returned to the original gain value. 
 
     
     
         6 . A method according to  claim 1 , in which the first representative loudness P value is received from a playout automation system. 
     
     
         6 . A method according to  claim 6  in which:
 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 (P+C)/2P times higher than the original gain value. 
 
     
     
         8 . A method according to claim  7  in which the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value and is after the junction returned smoothly to the original value. 
     
     
         9 . A method according to  claim 1 , in which the time-varying gain control is applied to the content after the junction. 
     
     
         10 . 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:
 receiving a first representative loudness value P for content before the junction from a playout automation system; and   applying a time-varying gain control in order to bring the loudness smoothly from the first representative value P to a second representative value C representing a loudness value for content after the junction.   
     
     
         11 . A method according to  claim 10 , in which:
 the audio gain applied to the content has an original gain value;   the first representative loudness measure P is compared with the second representative loudness measure C; and   when P<C the audio gain applied to the content is reduced shortly before the junction by the ratio P/C and is restored gradually to the original gain value after the junction.   
     
     
         12 . A method according to  claim 10 , wherein the time-varying gain control is applied at least before the junction. 
     
     
         13 . A method according to  claim 11 , comprising the further step of applying a time-varying gain control after the junction. 
     
     
         14 . A method according to  claim 10 , wherein the time-varying gain control is applied at least after the junction. 
     
     
         15 . A method according to  claim 10 , wherein said second representative loudness value C for content after the junction is received from the playout automation system. 
     
     
         16 . A method according to  claim 15  in which:
 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 (P+C)/2P times higher than the original gain value. 
 
     
     
         17 . A method according to  claim 16  in which the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value and is after the junction returned smoothly to the original value. 
     
     
         18 . 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: receiving from a playout automation system first P and second C representative loudness values for content respectively before and after the junction; and applying a time-varying gain control before and after the junction in order to smooth loudness around the junction. 
     
     
         19 . A method according to  claim 18  in which:
 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 (P+C)/2P times higher than the original gain value. 
 
     
     
         20 . A method according to  claim 19  in which the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value and is after the junction returned smoothly to the original value.