Audio Decoder DRC Metadata Selection for Real-Time Loudness Control

The patent applies preliminary action by calculating and storing loudness and dynamic range control parameters during the audio encoding phase. The encoder analyzes the audio program and determines DRC parameters in advance, storing them as metadata in the bitstream. This allows the decoder to retrieve pre-calculated parameters without performing time-consuming analysis during playback, thus resolving the contradiction between measurement accuracy and processing time.

The patent resolves this contradiction by performing the time-consuming loudness analysis and parameter calculation in advance during the encoding phase, rather than in real-time during playback. The encoder computes accurate loudness and DRC parameters from the complete audio program and stores them as metadata. During playback, the decoder simply retrieves these pre-calculated parameters, achieving both high encoding speed and accurate loudness management.

The patent applies local quality by providing different sets of DRC parameters optimized for specific playback conditions (e.g., different loudspeaker configurations, listening environments). The metadata includes multiple parameter sets with each set tailored to particular playback scenarios. The decoder selects the appropriate parameter set based on the actual playback conditions, thus achieving high adaptability without transmitting all possible parameter sets, thereby managing metadata volume efficiently.