Loudness Measurement and Adjustment for Automated, File-Based Environments

AudioTools Loudness Control Server

The AudioTools Loudness Control Server is an enterprise-level software suite for faster–than–real-time automated processing, measurement, and control of loudness in video and audio programs. AudioTools Loudness Control Server is a smart choice for streamlining PCM, Dolby E, or Dolby Digital and Dolby Digital Plus operations in a file-based environment

Running on Microsoft Windows, AudioTools Server gathers all of the functions needed to maintain consistent volume into one, software-based system that seamlessly integrates with existing service-oriented architectures without need for additional hardware.

Measure and Maintain Loudness

AudioTools Loudness Control Server is a purpose-built configuration of the AudioTools Server platform that performs measurement and adjustment of loudness based on ITU-R BS.1770 and according to European EBU R 128 recommendations, enabling compliance with the CALM Act in the US and other international loudness regulations.

AudioTools Loudness Control Server Provides:

  • Loudness measurement & adjustment according to all international standards & recommended practices
  • PCM, Dolby E, Dolby Digital & Dolby Digital Plus encoding & decoding
  • Loudness control driven by Program Loudness or Dolby Dialogue Intelligence™
  • Seamlessly handles mixed PCM & Dolby content, in parallel
  • Integration through Web Services or Watched Folders
  • MXF & QuickTime® audio essence extraction/rewrapping
  • Faster than realtime operation

The Recommended Practice

A compliant Program Loudness algorithm must analyze an entire show before it can be processed and sent on its way. An offline or file–based processor can measure and process mutilple programs at faster–than–realtime speeds. In contrast to the fully manual and realtime strategies, a file–based approach can also change the program playout level without changing the original loudness level by manipulating loudness metadata.

For true compliance, without the loss of fidelity and dynamic range inherent in compression and limiting, R 128 and the ATSC recommend a file-based scaling device, which offers several advantages over realtime operation. These include higher fidelity, along with preservation of the creators’ artistic intent. Improved fidelity is possible because of the absence of multiple and/or drastic dynamic range reduction and peak limiting that is required when there is no foreknowledge of what are the amplitude and dynamic range characteristics of incoming material.

R 128 provides well defined measurement recommendations, in conjunction with circumscribed workflow guidance and specific best practices, The overwhelming value of file–based workflows are throughput and consistency, offloading tedious repetitive loudness adjustment chores to an automated process that produces uniform output. This is especially applicable for legacy content that requires adjustment.

Content producers are sensitive about broadcasters modifying their content. Since file–based Program Loudness Adjustment is only a simple gain change, dynamic range and mix balance is maintained. In addition, since objective measurement precludes any bias, broadcasters are able to “reject with respect” any material that falls outside of established norms.

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