Invalidity dossier
US 8315398
System for adjusting perceived loudness of audio signals
Current assignee: DTS Inc
Added 9/23/2026, 8:43:41 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US8315398B2
Title: System for adjusting perceived loudness of audio signals
Patent number / application: US8315398B2; Application US12/340,364
Inventor: Themis Katsianos
Assignee: Original assignee DTS LLC; current assignee listed as DTS Inc. (the source cautions that listed assignees may be inaccurate and that no legal analysis was performed).
Key dates (as listed, and characterized by the source as assumptions): Priority date 2007-12-21; filing date 2008-12-19; publication of US20090161883A1 on 2009-06-25; grant/publication of US8315398B2 on 2012-11-20. Status is listed as active with an adjusted expiration of 2030-11-01.
Purpose and plain-language scope: The patent addresses adjusting an audio signal's loudness so it stays at a desired level. Loudness is described as a subjective auditory quantity, measured in "phon," that varies with frequency—unlike sound pressure in dB. Modeling the human ear with complex, high-order filters can consume significant computing resources, limiting use in devices such as televisions and car audio systems. The disclosed approach estimates loudness using processing-efficient techniques: lower-order filters approximating the ear's filter bank, decimating the signal to reduce samples processed, processing fewer than all channels, and smoothing gain coefficients rather than the output signal. This can let lower-capability processors dynamically adjust loudness.
The described subject matter includes: receiving an electronic audio signal and determining loudness of a portion using approximation filters that approximate auditory filters; computing at least one gain so loudness remains substantially constant for a period; and applying that gain. Multi-channel variants include selecting a dominant channel, and gains may be computed for a selected channel then applied to each channel. A phase-analysis method for distinguishing background noise is also described, as is a system using IIR band-pass filters approximating human hearing. Drawings include FIGS. 1A–11, with example C-weighting and inverted weighting curves.
What the excerpt does not establish: It is expressly marked as an excerpt with omitted text ("consult the source for omitted text"). It does not provide the full claims, the detailed description, or complete figure content, so the precise claim scope cannot be confirmed from this text alone. It does not establish validity, enforceability, litigation history, or prior-art relationships.
Source: https://patents.google.com/patent/[US8315398](/patent/US8315398)/en
Generated 10/1/2026, 9:41:14 PM
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Assignment history
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Prior art
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