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US 11,907,611 B2Granted
Deferred loudness adjustment for dynamic range control
AssigneeApple Inc.
InventorFrank Baumgarte
Life of this patent
Estimating the term…
Abstract
A bitstream is obtained by a decoder side, that contains an encoded version of an audio signal and an instantaneous loudness sequence of the audio signal. The instantaneous loudness sequence has not been loudness normalized. A dynamic range control, DRC, gain sequence is produced by applying the instantaneous loudness sequence to a DRC characteristic, with loudness normalization. The DRC gain sequence is applied to the decoded audio signal. Other aspects are also described and claimed.
Claims21
An audio decoder apparatus comprising:
- a processor;
- and
- memory having stored therein instructions that configure the processor to obtain a bitstream, the bitstream comprising:
- an encoded version of an audio signal,
- a first dynamic range control, DRC, gain sequence, that was determined by an encoder side process applying the audio signal to a first DRC characteristic,
- a loudness normalization gain that was applied by the encoder side process when determining the first DRC gain sequence,
- an index of the first DRC characteristic, wherein the index identifies or points to the first DRC characteristic, and
- a plurality of instances over time of an integrated loudness update.
5 more elements
An audio decoder apparatus comprising:
- a processor;
- and
- memory having stored therein instructions that configure the processor to obtain a bitstream, the bitstream comprising:
- an encoded version of an audio signal,
- a first dynamic range control, DRC, gain sequence, that was determined by an encoder side process applying the audio signal to a first DRC characteristic,
- an index of the first DRC characteristic, wherein the index identifies or points to the first DRC characteristic,
- a plurality of instances over time of an integrated loudness update, and
- a flag, wherein when the flag has a first value the bitstream contains an encoder side loudness normalization gain, or when the flag has a second value the bitstream does not contain the encoder side loudness normalization gain.
5 more elements
An audio decoder apparatus comprising:
- a processor;
- and
- memory having stored therein instructions that configure the processor to obtain a bitstream, the bitstream comprising:
- an encoded version of an audio signal,
- a first dynamic range control, DRC, gain sequence, that was determined by an encoder side process applying the audio signal to a first DRC characteristic,
- an index of the first DRC characteristic, wherein the index identifies or points to the first DRC characteristic,
- a plurality of instances over time of integrated loudness update, and
- an encoder side DRC normalization gain;
- wherein the processor compensates for the encoder side DRC normalization gain when applying a decoder side DRC loudness normalization.
6 more elements
A digital audio method comprising:
- obtaining a bitstream, the bitstream comprising an encoded version of an audio signal, a first dynamic range control, DRC, gain sequence, that was determined by an encoder side process applying the audio signal to a first DRC characteristic, an index of the first DRC characteristic, wherein the index identifies or points to the first DRC characteristic, and a plurality of instances over time of integrated loudness update;
- using the index to obtain an inverse DRC characteristic;
- performing loudness normalization after applying the inverse DRC characteristic to the first DRC gain sequence, to produce a normalized loudness sequence;
- applying the normalized loudness sequence to a second DRC characteristic to produce a second DRC gain sequence;
- and
- applying the second DRC gain sequence to the audio signal to produce compressed audio.
3 more elements
Dependencies are inferred from the claim text.