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.

Proceedings overview

Total AIA trial proceedings on U.S. Patent 6,278,387: 0 — zero IPRs, zero PGRs, zero CBMs, by every source checked. The USPTO Open Data Portal (PTAB proceedings on file) returns no AIA trial proceedings for this patent as of the most recent ingest, and web searches across multiple query formulations ("6278387" IPR, "US6278387" PTAB, "6,278,387" inter partes review, "6278387" Rayskiy, ptab.uspto.gov trial search 6278387) returned no proceeding numbers, dockets, decisions, or appeals referencing this patent. The only near-miss hits were unrelated: U.S. Patent 6,690,387 (a Koninklijke Philips IPR, not this patent) and U.S. Patent 6,278,387A in an unrelated heating-cable application identifier string.

Bottom-line defensive posture: This patent has never been challenged at the PTAB. It is untested, not hardened — but it is also expired (status: "Expired – Lifetime"; 20-year term ran 1999-09-28 → 2019-09-28), which is the dominant defensive fact. No claims have been canceled by the Board because no petition was ever filed; conversely, no claims have been sustained by the Board either. There is no PTAB estoppel of any kind against any party, because § 315(e)(2) estoppel attaches only after a final written decision (or § 315(e)(1) after a petition is granted).

No per-proceeding sections follow because there are no proceedings to report — I will not fabricate proceeding numbers, panels, grounds, or dispositions.

Strategic summary

Claim status: all 23 claims (independent claims 1, 9, 16; dependent claims 2–8, 10–15, 17–23) are UNTESTED at the PTAB. No AIA petition has been filed, instituted, or decided against this patent. The patent's claims are therefore neither CANCELED nor SUSTAINED by any Board decision — they simply have never been the subject of an IPR/PGR/CBM. The only relevant "status" is the patent's expiry on 2019-09-28, which means the claims cannot be enforced against any act occurring after that date, and any damages claim for pre-expiry acts would have had to satisfy 35 U.S.C. § 286's six-year lookback (i.e., a complaint filed by roughly 2019-09-28 at the latest for pre-expiry infringement).

Estoppel landscape — clean slate. Because no IPR was ever instituted, no party is barred by § 315(e)(1) or § 315(e)(2). A defendant facing assertion today has the full universe of prior art available: every § 102 and § 103 ground that could have been raised in an IPR (including art never presented to the examiner, e.g., the SOLA literature, MPEG-1/MPEG-2 sub-band filter-bank references, and time-scale-modification papers predating the 1999-09-28 priority date) remains fully available in district court. There is no risk of an "IPR estoppel" trap here because there is no IPR.

Pattern signals — none. No petitioner has filed anything, so there is no repeated-petitioner pattern (no General Plastic / Fintiv issues). The patent owner (Conexant → Lakestar Semi → Conexant Systems, LLC → Synaptics Incorporated) has never litigated this patent at the PTAB, and — per the prior litigation search — has no known district court enforcement history on it either. No defensive aggregator (Unified Patents, OpenSky, etc.) appears in any chain for this patent. The absence of PTAB activity, combined with the patent's quiet post-issuance history (only routine security-interest assignments) and its 2019 expiry, strongly suggests this patent was never commercially asserted in a way that would attract an IPR.

Recommended next steps

• There is no PTAB activity — say so plainly, and use the expiry, not the IPR absence, as the primary lever. If a demand letter or complaint cites US 6,278,387, the threshold response is: the patent expired on 2019-09-28; it cannot be enforced against any accused activity after that date (no injunction, no ongoing royalties), and any alleged pre-expiry damages require pleading and proof of infringement within the § 286 six-year window, which closed in 2019. A post-expiry demand letter asserting this patent is close to sanction-bait on its face.
• If you want belt-and-suspenders verification before relying on "no PTAB proceedings": run the patent number directly in the USPTO's PTAB E2E / PTAB Trial Search (https://ptab.uspto.gov) and the PTAB Bulk Data Search tool (patent-number quick lookup), and pull the USPTO Patent Center file wrapper for US09/407,465 to confirm there is no inter partes reexamination (the pre-AIA analog) lurking either. My searches found none, but a direct E2E lookup by patent number is the authoritative confirmation.
• Preserve the invalidity arsenal. Because there is no estoppel, every § 102/§ 103 ground remains open. If you litigate, the strongest art will be the pre-1999 time-scale-modification and MPEG sub-band literature (e.g., the SOLA algorithm publications from the 1980s–1990s; ISO-IEC/ITC1 SC29/WG11 DIS 11172, April 1992 — which the specification itself cites as the basis for the 32-sub-band filter bank; and the "Kmin–Kmax per-sub-band search range" table, which is a strong § 103 target given the specification admits the ranges are merely derived from each sub-band's lowest-frequency period).
• One honest caveat: web and ODP searches returning nothing is not absolute negative proof. There is no PTAB proceeding on file per the USPTO Open Data Portal, and no web-visible proceeding exists, but if you need a formal certification for litigation, obtain a PTAB E2E docket search and a PRD (Patent Review Data) download filtered on this patent number, and have counsel confirm the absence before representing it to a court.

I attempted to query the USPTO Assignment Center and run supplementary web searches for correspondent-of-record data (reel/frame-specific queries for 010427/0863, 043786/0267, 038777/0885, etc.). All searches returned empty results and the tool session limit was reached before the Assignment Center could be accessed. The full assignment record below therefore comes from the USPTO-derived legal-events data embedded in the authoritative Google Patents record supplied with the task (reel/frame, conveyance type, parties, and effective dates are all present there). Correspondent-of-record attorney names could not be retrieved and are NOT inferred or fabricated below; signal 3 is accordingly marked unclear.

Inventors

• Maksim Y. Rayskiy — sole named inventor. Employer at filing: Conexant Systems, Inc. (per the 1999-11-26 recorded assignment of rights from Rayskiy to Conexant, reel 010427/0863, effective 1999-09-29 — one day after the filing date).

Unusual-pattern check: not present. There is a single inventor (not a team), and there is no record of the inventor departing Conexant within 12 months of filing — he assigned his rights to Conexant at filing, which is the ordinary course. Nothing here suggests a portfolio fire-sale precursor.

Original assignee

• Conexant Systems, Inc. (issuing entity; the Nov 1999 inventor assignment names "CONEXANT SYSTEMS, INC." as assignee). Google Patents normalizes the original assignee to the current name "Conexant Systems LLC," which is the product of the 2017 name change — the entity of record at issue was Conexant Systems, Inc.
• Line of business: Fabless semiconductor company — PC audio codecs (including AC'97-class audio), modem/DSP chipsets, and later IoT and voice-processing silicon. An MPEG-compliant audio codec with variable-rate playback (the claimed subject matter) is squarely within Conexant's product space, so it is plausible but not confirmed that a shipped product embodied the claims; I have no verified product teardown or datasheet tie to the specific SOLA-per-sub-band claims.
• Current status: Not an independent operating company. The record shows Conexant Systems, Inc. → Conexant Systems, LLC (name change, effective 2017-03-20) → Synaptics Incorporated (assignment effective 2017-09-01, recorded 2017-09-07), matching Synaptics' public acquisition of Conexant's audio/voice business in 2017. Synaptics (NASDAQ: SYNA) is a public operating company.

Assignment timeline

All 12 recorded conveyances below are taken from the USPTO-derived legal-events table in the supplied patent record. Execution dates and correspondent names are not separately retrievable from the supplied data (the "effective date" shown is the date the instrument states; the recording date is the USPTO-verified date). Correspondent fields are marked not retrieved rather than guessed.

• 1999-09-29 (effective) / recorded 1999-11-26 — Reel 010427 / Frame 0863

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Maksim Y. Rayskiy (inventor)
  • Assignee: Conexant Systems, Inc.
  • Correspondent: not retrieved
  • Context: Original inventor-to-company assignment at filing; standard.

• 1998-12-21 (effective) / recorded 2000-01-03 — Reel 010450 / Frame 0899

  • Conveyance: Security Interest
  • Assignor: Conexant Systems, Inc.
  • Assignee: Credit Suisse First Boston
  • Correspondent: not retrieved
  • Context: Lender collateral grant (debt financing), not an ownership transfer.

• 2001-10-18 (effective) / recorded 2001-11-05 — Reel 012252 / Frame 0865

  • Conveyance: Release of Security Interest
  • Assignor: Credit Suisse First Boston
  • Assignee: Conexant Systems, Inc.; Brooktree Corporation; Brooktree Worldwide Sales Corporation; Conexant Systems Worldwide, Inc.
  • Correspondent: not retrieved
  • Context: Release of the 2000 lien; routine.

• 2006-11-13 (effective) / recorded 2006-11-22 — Reel 018711 / Frame 0818

  • Conveyance: Security Agreement
  • Assignor: Conexant Systems, Inc.
  • Assignee: Bank of New York Trust Company, N.A.
  • Correspondent: not retrieved
  • Context: New lender collateral grant (BNY as indenture trustee); routine debt financing.

• 2010-01-28 (effective) / recorded 2010-03-01 — Reel 023998 / Frame 0838

  • Conveyance: Release by Secured Party
  • Assignor: The Bank of New York Mellon Trust Company, N.A. (formerly The Bank of New York Trust Company, N.A.)
  • Assignee: Conexant Systems, Inc.
  • Correspondent: not retrieved
  • Context: Release of the 2006 security agreement.

• 2010-03-10 (effective) / recorded 2010-03-11 — Reel 024066 / Frame 0075

  • Conveyance: Security Agreement
  • Assignor: Conexant Systems, Inc.; Conexant Systems Worldwide, Inc.; Conexant, Inc.; Brooktree Broadband Holding, Inc.; and others
  • Assignee: The Bank of New York, Mellon Trust Company, N.A.
  • Correspondent: not retrieved
  • Context: Re-filed consolidated lender security agreement across the Conexant group.

• 2014-03-10 (effective) / recorded 2016-05-06 — Reel 038631 / Frame 0452

  • Conveyance: Release by Secured Party
  • Assignor: The Bank of New York Mellon Trust Company, N.A.
  • Assignee: Conexant Systems, Inc.; Conexant Systems Worldwide, Inc.; Conexant, Inc.; Brooktree Broadband Holding, Inc.
  • Correspondent: not retrieved
  • Context: Release of the 2010 security agreement, recorded ~2 years late.

• 2013-07-12 (effective) / recorded 2016-05-20 — Reel 038777 / Frame 0885

  • Conveyance: Change of Name
  • Assignor: Conexant Systems, Inc.
  • Assignee: Lakestar Semi Inc.
  • Correspondent: not retrieved
  • Context: Corporate rename of Conexant Systems, Inc. to Lakestar Semi Inc., recorded nearly three years late (2016).

• 2013-07-12 (effective) / recorded 2016-05-23 — Reel 038803 / Frame 0693

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Lakestar Semi Inc.
  • Assignee: Conexant Systems, Inc.
  • Correspondent: not retrieved
  • Context: Immediate reassignment back from Lakestar Semi Inc. to Conexant Systems, Inc., same effective date as the rename — a corrective/cleanup pair (name-change loop reversed), not a transfer to a distinct entity.

• 2017-03-20 (effective) / recorded 2017-06-26 — Reel 042986 / Frame 0613

  • Conveyance: Change of Name
  • Assignor: Conexant Systems, Inc.
  • Assignee: Conexant Systems, LLC
  • Correspondent: not retrieved
  • Context: Corporate rename to LLC form ahead of the Synaptics acquisition.

• 2017-09-01 (effective) / recorded 2017-09-07 — Reel 043786 / Frame 0267

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Conexant Systems, LLC
  • Assignee: Synaptics Incorporated
  • Correspondent: not retrieved
  • Context: Operating-business acquisition — Synaptics buys Conexant's audio/voice business; patent moves to the acquiring public operating company.

• 2017-09-27 (effective) / recorded 2017-09-27 — Reel 044037 / Frame 0896

  • Conveyance: Security Interest
  • Assignor: Synaptics Incorporated
  • Assignee: Wells Fargo Bank, National Association
  • Correspondent: not retrieved
  • Context: Synaptics grants lender security interest (credit-facility collateral); not an ownership transfer.

Net result: ownership never left the operating-company sphere. The patent issued to Conexant, was encumbered/released by lenders, passed through two name-change/reverse recordings (Lakestar loop), and ended at Synaptics.

Timeline diagram

timeline
    title Ownership of US 6278387
    1999 : Filed by Conexant
         : Inventor assignment recorded
    2000 : Credit Suisse security interest
    2001 : Patent issued
         : Credit Suisse lien released
    2006 : BNY Mellon security agreement
    2010 : BNY Mellon lien released
         : New BNY Mellon agreement
    2016 : Lakestar Semi name change
         : Reassignment to Conexant
    2017 : Renamed Conexant Systems LLC
         : Acquired by Synaptics
         : Wells Fargo security interest

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The only LLC/Inc. entities appearing as assignees are corporate renames of the operating company itself: Lakestar Semi Inc. (reel 038777/0885) and Conexant Systems, LLC (reel 042986/0613). No "IP / Patents / Licensing / Holdings / Ventures" LLC, no registered-agent-only address, and no single-purpose Delaware/Texas licensing LLC appears anywhere in the chain. Ownership stayed inside Conexant/Synaptics the entire time.

2. Known asserter in the chain — not present. Assignees across all 12 conveyances are: Conexant Systems, Inc.; Credit Suisse First Boston (lender); Bank of New York Trust Company, N.A. / BNY Mellon Trust (lender); Lakestar Semi Inc. (Conexant rename); Conexant Systems, LLC (rename); Synaptics Incorporated (public operating company, NASDAQ: SYNA); Wells Fargo Bank (lender). None match Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp., or Spangenberg entities.

3. Repeat correspondent across the chain — unclear. Correspondent-of-record names could not be retrieved in this session (USPTO Assignment Center unreachable via available tools; reel/frame web searches returned no results). Per the constraint against fabrication, this signal is left unmarked rather than guessed. It is the one gap in this analysis.

4. Cascading transfers — not present. The only back-to-back recordings — reels 038777/0885 (Change of Name to Lakestar Semi Inc.) and 038803/0693 (Assignment back to Conexant), both effective 2013-07-12 and recorded within three days in May 2016 — are a same-day name-change-and-reverse corrective pair, not chained transfers through distinct LLCs with shifting ownership.

5. Pre-litigation transfer — not present. No litigation involving this patent was found in the prior analysis (no district-court or CAFC docket entries). The 2017 transfer to Synaptics (reel 043786/0267, effective 2017-09-01) corresponds to a public business acquisition, not a standing-arrangement filing timed to a complaint.

6. Bankruptcy fire-sale — not present in the assignment record. No trustee, receiver, or § 363 sale conveyance appears. The security agreements (reels 010450/0899, 018711/0818, 024066/0075) and releases (reels 012252/0865, 023998/0838, 038631/0452) are ordinary lender collateral filings. Whether Conexant's underlying restructuring involved a bankruptcy proceeding is outside this assignment record and I cannot confirm it either way.

7. Privateering — not present. The final transfer runs to an operating company (Conexant Systems, LLC → Synaptics Incorporated, reel 043786/0267), not from one to a third-party NPE. No SEC or press evidence of a privateering arrangement surfaced.

8. Defensive aggregator (anti-NPE) — not present. The chain terminates at Synaptics Incorporated, a public operating company, not at RPX, AST, LOT Network, Unified Patents, or OIN.

Verdict

Operating-company assertion — with the explicit caveat that this characterization rests on assignee identity rather than observed enforcement.

The chain is fully documented (12 recorded conveyances) and never touches an NPE: ownership runs Conexant Systems, Inc. → (lender liens/releases) → name-change loop → Conexant Systems, LLC → Synaptics Incorporated (reel 043786/0267, recorded 2017-09-07), a public operating company that acquired Conexant's audio business. No shell LLC, known asserter, cascading LLC chain, pre-litigation transfer, bankruptcy-sale conveyance, privateering, or defensive-aggregator terminus appears in the record. However, no litigation involving this patent was found and the patent expired 2019-09-28 (20 years from filing), so there is no evidence Synaptics ever asserted it — the "assertion" label is inferred from Synaptics being an operating company whose product space overlaps the claims, not from any observed suit.

Verify at the USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent number 6278387; indexed copy at https://assignment.uspto.gov/patent/index.html). The one unresolved item is correspondent-of-record attorney data (signal 3), which requires direct Assignment Center access to close.

I'll search for the specific patent 6278387 and each of its cited references to build the prior art analysis.

Let me search for the remaining three cited references.

I have gathered the available data. Note: I reached the search step limit before completing dedicated lookups for US5786778 and US5896099; for those two, I rely on the authoritative citation data in the patent's own bibliographic record (titles, dates, assignees) plus general knowledge, and I flag that explicitly below.

Prior Art Analysis — U.S. Patent 6,278,387 (US6278387B1)

0. Target-patent confirmation (identifier check)

I searched for the literal number 6278387 (and US6278387B1). All results returned the same patent — "Audio encoder and decoder utilizing time scaling for variable playback," inventor Maksim Y. Rayskiy, assignee Conexant Systems, Inc., filed 1999-09-28 (US09/407,465), issued 2001-08-21, now expired (2019-09-28). Sources: Google Patents (patents.google.com/patent/US6278387), FreePatentsOnline (6278387.html), Justia (patents.justia.com/patent/6278387), and the USPTO-mirrored PDF (patentimages.storage.googleapis.com/.../US6278387.pdf). No similar-number results (e.g., 627838, 6,278,837 variants) were substituted. I did not run a direct USPTO Patent Center/Public Search query in this session; the Google Patents/FreePatentsOnline records mirror USPTO bibliographic data and are consistent with the authoritative patent text provided.

1. Scope of the citation record

US6278387B1 lists six U.S. patent citations (all examiner-cited, marked "*" in the record). All six published before the 1999-09-28 filing date, so each is available as prior art under pre-AIA 35 U.S.C. § 102(a); all but US5896099 also qualify under § 102(b) (published more than one year before filing, i.e., before 1998-09-28); US5896099 additionally qualifies under § 102(e) (U.S. application by another filed 1995-06-30, before the invention date).

Headline assessment: None of the six references discloses the invention's core — a per-sub-band, time-domain time-scaling module (SOLA) with best-averaging-point search — so none appears to fully anticipate any independent claim (1, 9, or 16). Their relevance is concentrated on the conventional codec/decode-conversion elements (sub-band splitting, psycho-acoustic bit allocation, decoding, D/A conversion) that the specification itself describes as background. Below, each reference is analyzed for which claim elements it could potentially read on.

2. Reference-by-reference analysis

2.1 US4862168A — "Audio digital/analog encoding and decoding"

2.2 US4933675A — "Audio digital/analog encoding and decoding"

2.3 US5451954A — "Quantization noise suppression for encoder/decoder system"

2.4 US5712635A — "Digital to analog conversion using nonuniform sample rates"

2.5 US5786778A — "Variable sample-rate DAC/ADC/converter system"

2.6 US5896099A — "Audio decoder with buffer fullness control"

3. Consolidated § 102 assessment

Key takeaway. Every independent claim of US6278387B1 (1, 9, 16) requires the variable-playback/time-scaling feature: claim 1's rate adjust module, claim 9's time scaling module time-stretching per sub-band, and claim 16's best-averaging-point overlap-and-average method (SOLA). None of the six cited references — all of which are conventional sub-band codec, quantization-noise, or sample-rate-conversion art — discloses that feature. None is a realistic § 102 anticipation reference for the independent claims; the strongest would be US5451954 for the sub-band codec structure of claims 6–8 and the decoder sub-elements of claim 9 if combined with the SOLA literature (a § 103 argument, not § 102). The specification's own internal citation — ISO-IEC/ITC1 SC29/WG11 DIS 11172 (MPEG-1 audio, April 1992) — and the 1980s–1990s SOLA publications (Roucos & Wilgus, 1985; Moulines & Laroche, 1999 and predecessors) would be the more promising § 102/§ 103 art, but those are not among the six USPTO citations of record.

Honest caveats: (1) Direct USPTO Patent Center/Public Search confirmation was not run this session; Google Patents/FreePatentsOnline/Justia all match the supplied authoritative record, so identifier risk is minimal. (2) Functional descriptions of US5786778 and US5896099 are unverified beyond their bibliographic data due to the search step limit. (3) "Cited by examiner" marks on all six indicate the examiner considered them background; none was relied on as primary anticipation art on the face of the record.