System and method for leveling loudness variation in an audio signal
AssigneeDolby Laboratories Licensing Corporation
InventorsAndrew P. Reilly, Michael Smithers, Jeffrey Riedmiller
Life of this patent
Estimating the term…
Abstract
Systems and methods for leveling loudness variation in an audio signal are described. Embodiments use both a perceptual leveling algorithm and a standards-based loudness measure together to minimize audio process artifacts and ensure that the measured loudness of the processed audio is close to a required measure, according to a particular standard measurement of loudness. These systems and methods can be used either offline or in real-time.
Claims24
A method for leveling loudness variation in an audio signal, the method comprising:
- processing the audio signal for short term loudness comprising:
- receiving the audio signal and a desired loudness of the audio signal;
- and
- adjusting a short term loudness of the audio signal using a short term integration time and the received desired loudness of the audio signal, to yield an adjusted audio signal;
- wherein adjusting the short term loudness comprises using spectral analysis and models of human hearing to adjust the audio signal;
- processing for long term loudness comprising:
- measuring an actual loudness of the adjusted audio signal using a long term integration time;
- wherein the long term integration time is longer than the short term integration time;
- and
- output a single loudness number,
- calculating a gain value using a difference between the desired loudness and the actual loudness of the audio signal;
- and
- modifying the audio signal using the gain value.
A system for leveling loudness variation in an audio signal, the system comprising:
- a short term loudness leveling processor configured to receive the audio signal and a desired loudness of the audio signal, and configured to adjust a short term loudness of the audio signal using a short term integration time, to yield an adjusted audio signal;
- wherein adjusting the short term loudness comprises using spectral analysis and models of human hearing to adjust the audio signal;
- a long term loudness leveling processor configured to measure an actual loudness of the audio signal using a long term integration time;
- wherein the long term integration time is longer than the short term integration time;
- a loudness to gain processor configured to calculate a gain value using a difference between the desired loudness and the actual loudness of the audio signal;
- and
- an audio modification processor configured to modify the adjusted audio signal using the gain value.
A computer readable storage having computer executable instructions embedded thereon and executed by a processor for performing the steps of:
- processing a audio signal for short term loudness comprising:
- receiving the audio signal and a desired loudness of the audio signal;
- and
- adjusting a short term loudness of the audio signal using a short term integration time and the received desired loudness of the audio signal, to yield an adjusted audio signal;
- wherein adjusting the short term loudness comprises using spectral analysis and models of human hearing to adjust the audio signal;
- processing for long term loudness comprising:
- measuring an actual loudness of the adjusted audio signal using a long term integration time;
- wherein the long term integration time is longer than the short term integration time;
- and
- output a single loudness number,
- calculating a gain value using a difference between the desired loudness and the actual loudness of the audio signal;
- and
- modifying the audio signal using the gain value.
Dependencies are inferred from the claim text.