Loudness is a subjective measure of how loud an audio signal is perceived. Due to commercial pressures loudness has been exploited in broadcasts to attract and reach viewers and listeners. By means of signal processing it is possible to increase the loudness of an audio signal and still meet the contemporary legislated signal levelling requirements. With an aspiration to achieve equal average loudness between all broadcasting programmes the European Broadcasting Union have issued a standard that proposes methods to quantify loudness. This thesis applies those loudness quantities and proposes an online algorithm that adaptively normalises the loudness of audiovisual broadcasts without affecting the dynamics within programmes. The main application of the algorithm is to normalise the audio in broadcasting and distributing equipment with real-time requirements. The results were derived from simulations in Matlab using commercial broadcasts. The results showed that for certain types of broadcasts the algorithm managed to reduce the variation in average programme loudness with minor effects on dynamics within programmes. / Loudness är ett subjektivt mått på hur högljudd en ljudsignal uppfattas. Till följd av kommersiellt tryck har loudness utnyttjats i sändningar för att locka och nå tittare. Genom signalbehandling är det möjligt att öka loudness-nivån på en ljudsignal och fortfarande uppfylla dagens lagstadgade signalnivåkrav. Med strävan att uppnå en lika medel-loudness-nivå mellan alla program har Europeiska radio- och TV-unionen publicerat en standard som föreslår metoder för att kvantifiera loudness. Denna rapport tillämpar dessa metoder och föreslår en algoritm som adaptivt normaliserar loudness-nivån i audiovisuella sändningar utan att påverka dynamiken inuti program. Huvudtillämpningen för algoritmen är att normalisera ljudsignalen i sändnings- och distributionsutrustning med realtidskrav. Resultaten erhölls från simuleringar i Matlab där kommersiella sändningar användes. Resultaten visade att för vissa typer av sändningar lyckades algoritmen minska variationen i medel-loudness-nivå med smärre påverkan på dynamik inuti program.

How loud is todays movies? I have been investigating the differences between loudness in American and Swedish flm making. Also, what difference does variation depending on country of distribution, language spoken and audio formats make? I applied the loudness levelling standard EBU r128 as take-off point for my study as I believe it will be the standard for how future audio tracks will be played and mixed.

In order to investigate what work methods professional audio engineers use to comply with the EBU R 128 recommendation in live TV broadcasts, an interview study was conducted. The purpose of the study was to provide novice and professional engineers with information about what work methods to use when trying to comply with the current loudness standards in live situations. Furthermore, the study may also contribute with new perspectives to the already existing production guidelines developed by the European Broadcasting Union (EBU). Five professional audio engineers from the TV broadcasting industry were interviewed. The subjects in this study suggest another way of measuring the loudness of live broadcasted music shows. Instead of measuring the whole program, the subjects argue that loudness measurements of the dialogue may be a more appropriate measurement method. Furthermore, a widening of the tolerance window of the EBU R 128 recommendation is suggested for music shows. The current tolerance window of  1 LU needs to be expanded to  1.5-2 LU, according to the subjects in this study and for music shows in particular.