US 6278387

Summary — U.S. Patent 6,278,387 (US6278387B1)

Search results note

I searched the USPTO/Google Patents records and CAFC 2026 docket indexes for the specific number 6278387. The patent database records are consistent across sources (Google Patents, FreePatentsOnline). No CAFC appeal docket entries for 2026 (or any year) referencing this patent were found — searches for "6278387" CAFC, "6,278,387" appeal, and Synaptics/Conexant litigation involving this number returned no matching docket records. The patent expired in 2019 (see status below), so any CAFC 2026 activity would be unexpected; I have no authoritative basis to assert any pending appeal exists.

Bibliographic data

Abstract (verbatim)

An audio codec having an encoder and a decoder is disclosed. The encoder enables the compression of an audio signal for transmission or storage while the decoder receives a compressed audio signal for playback. A time scaling module within the decoder allows variation of the playback rate of the compressed audio signal. Further, no significant depreciation in the quality of pitch occurs as a result of varying the playback rate. The codec features a control for independently varying the playback rate and a module for delivering pitch compensation. The encoder utilizes a sub-band coding scheme (e.g., MPEG-1 and MPEG-2) wherein an audio signal is split into at least two frequency sub-bands for compression. ... The time scaling module time stretches or compresses an audio signal as desired using a synchronized overlap and add (SOLA) algorithm.

Plain-language overview of independent claims

Claim 1 — Audio codec (system). An audio codec that receives a first audio signal for encoding and a second audio signal for decoding, comprising: an encoder (with a memory and a processor that, in response to receiving the first audio signal, directs encoding of it into a digital code word); a decoder (with a memory and a processor that directs decoding of the second audio signal to enable playback); and a rate adjust module that permits variable playback of the second audio signal. In short: a combined encode/decode device whose playback speed is user-adjustable.

Claim 9 — Audio decoder (system). A decoder that receives a compressed audio bit stream having at least first and second frequency sub-bands, comprising: an input interface; an unformatter that unpacks the bit stream from its frame structure; an inverse bit allocate decoder that inversely allocates/de-quantizes the stream to recover input samples per sub-band; and a time scaling module that time-stretches the input samples in the time domain for each sub-band separately to enable variable playback. In short: a compressed-audio (e.g., MPEG sub-band) decoder that changes playback rate in the time domain, per sub-band, preserving pitch.

Claim 16 — Method of time-scaling (process). A method for manipulating audio samples having first and second sub-band frequencies: (1) receiving the samples; (2) forming, for each sub-band, an input frame and a first output frame; (3) computing a best averaging point within a search range for overlapping the input and first output frames; (4) overlapping the frames at that point; and (5) averaging the overlapped portions for each sub-band to form a second output frame. In short: the SOLA-style frame-overlap-and-average procedure — find the best alignment point, cross-fade, and average — applied per frequency sub-band.

The dependent claims add detail such as: MPEG-2/32-sub-band compliance (claims 7, 11, 17); the sub-band-dependent search range (Kmin–Kmax) based on sampling frequency (claims 13, 18); fade-in/fade-out averaging (claim 19); time compression or expansion (claims 14–15); and fixed vs. user-selectable input frame size (claims 20–23).

Uncertainty / caveats

• CAFC 2026 docket: No entries found for this patent number. I cannot confirm any appeal; given the patent expired in 2019, it is unlikely to be the subject of new 2026 appellate litigation, but I have no authoritative source confirming its absence from every docket listing.
• Current assignee: The Google Patents assignment chain lists Conexant Systems, Inc. → Lakestar Semi Inc. → Conexant Systems, LLC → Synaptics Incorporated (2017). I did not independently verify Synaptics' current recordal at the USPTO for this specific patent.
• The patent text provided (Google Patents) is authoritative for title, dates, claims, and abstract and is consistent with all search results returned; I found no conflicts requiring me to prefer search results over the supplied text.

Litigation Search Results — U.S. Patent 6,278,387 (US6278387B1)

No litigation involving U.S. Patent 6,278,387 was found.

I searched across multiple litigation-oriented sources and query formulations for the exact patent number 6278387 (and equivalents "6,278,387," "US6278387"):

Consistent with prior analysis

This result is consistent with the earlier patent-summary work: no CAFC (or any appellate) docket entries referencing this patent were found for any year, including 2026. The patent's assignment history shows only routine security-interest and ownership transfers (Conexant → Lakestar Semi → Conexant Systems, LLC → Synaptics Inc.), with no assignment event tied to litigation (e.g., no "litigation release," judgment, or settlement conveyance).

Assessment

• Known litigation: None. I have no authoritative basis to identify any plaintiff(s), defendant(s), jurisdiction, case number, filing date, or status for any case involving this patent.
• Why this is plausible: The patent expired (lapsed) on September 28, 2019 (20 years from filing, "Expired – Lifetime" status). Post-expiration, the patent cannot be enforced for damages or injunctive relief for acts after expiration, and past-damages claims would have had to be filed before the statute of limitations ran (6 years under 35 U.S.C. § 286), i.e., by roughly September 2019 for pre-expiration acts. This significantly reduces the likelihood of new litigation in 2026.
• Caveat (stated explicitly): Web/database searches returning no results is not an absolute negative proof. It is possible that an older district court case (e.g., a 2001–2019 case) exists that is not well-indexed in the free sources I queried (CourtListener, Google Patents, Unified Patents portal). If you need a definitive answer, I would recommend a paid docket search (PACER full-text search, Docket Navigator, or LexisNexis/RPX) across 2001–2019.

Conclusion: No litigation is known involving U.S. Patent 6,278,387 based on the available search results.