Metadata for loudness and dynamic range control

摘要

An audio normalization gain value is applied to an audio signal to produce a normalized signal. The normalized signal is processed to compute dynamic range control (DRC) gain values in accordance with a selected one of several pre-defined DRC characteristics. The audio signal is encoded, and the DRC gain values are provided as metadata associated with the encoded audio signal. Several other embodiments are also described and claimed.

主权项

1. A method for decoding audio during playback processing, comprising:
receiving an encoded audio signal; receiving metadata associated with the encoded audio signal, the metadata including a plurality of dynamic range control (DRC) gain values and an index of a previously selected DRC characteristic in accordance with which the DRC gain values were computed when the encoded audio signal was being generated; decoding the encoded audio signal to produce a decoded audio signal; selecting a current DRC characteristic from amongst a plurality of available DRC characteristics, wherein the selected current DRC characteristic is associated with the index; producing modified DRC gain values by i) applying the plurality of DRC gain values from the metadata to the current DRC characteristic to obtain a plurality of input levels, ii) selecting a target DRC characteristic from amongst the plurality of available DRC characteristics, and iii) applying the plurality of input levels obtained in i) to the target DRC characteristic; and applying the modified DRC gain values to the decoded audio signal to produce a DRC adjusted audio signal during playback processing.