KitPlus - The TV-Bay Magazine

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file-based content vs. live content are slightly different. File-based content allows multi-pass analysis of content offline, whereas that is not possible with live content. would encounter the original loudness problem. Different approaches can be taken for short-form and long-form content to achieve better results. Loudness control tools generally utilize metadata-based or audio normalization algorithms. Metadata- based control is primarily used with Dolby audio formats, where loudness- specific metadata such as dialnorm and dynamic range factors can be set per the user’s requirements. On the other hand, audio normalization algorithms modify the original PCM samples to achieve a target loudness profile. Good normalization algorithms should ensure that the correction process doesn’t lead to any kind of audio distortion. The correction cannot be a simple gain or attenuation process, as true peak and dynamic range are also vital parameters to be considered. Ignoring the dynamic range could lead to a situation where low audio levels become so low that audio is inaudible. Eventually, the viewer may increase the volume on the TV to hear the sound well, but The structural integrity of media files needs to be maintained during the correction process. After normalization of audio samples, audio will need to be re-encoded and rewrapped into the main media file. This step can potentially introduce encoding errors. If any media information is altered or lost during this step, it could adversely impact the content distribution chain. Obviously, broadcasters want a system that can monitor all aspects of loudness to ensure compliance with EBU-R128 and a superior audio experience for viewers. After performing comprehensive checks, the system should have the option to correct loudness issues and provide a report to broadcasters for identifying trends and eliminating loudness issues in the future. For a complete approach to audio loudness measurement, broadcasters should also add a live content monitoring solution to their workflow. Loudness monitoring and control systems are now quite mature and have been successfully deployed by broadcasters worldwide. KITPLUS - THE TV-BAY MAGAZINE: ISSUE 113 MAY 2016 | 59