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IPR2024-01175

Amazon.com Inc v. Nokia Technologies Oy

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1. Case Identification

2. Patent Overview

  • Title: Context-Based Arithmetic Coding for Image Compression
  • Brief Description: The ’701 patent discloses methods and systems for improving image and video compression efficiency using Context-Based Adaptive Binary Arithmetic Coding (CABAC). The invention purports to improve upon prior art CABAC methods by constructing enhanced context models for coding run-level data pairs, which represent quantized transform coefficients, by leveraging the statistical dependencies between a current number pair and a preceding one.

3. Grounds for Unpatentability

Ground 1: Obviousness over Tsai and VCEG-L28 - Claims 1-14, 17-31, and 34-40 are obvious over Tsai in view of VCEG-L28.

  • Prior Art Relied Upon: Tsai (Patent 5,818,877) and VCEG-L28 (an ITU-T standards proposal document titled "VLC concatenation for Intra coding").
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Tsai taught a context-based arithmetic coding system for compressing run/level data that utilized two distinct contexts: one for "run" information and one for "level" information. Tsai's system partitioned a symbol stream into a "location list" (containing run data) and a "level list," each coded with a separate adaptive context model. However, Petitioner asserted Tsai did not teach making this context assignment dependent on a value from a preceding run/level pair. This limitation was allegedly supplied by VCEG-L28, a proposal for the H.26L video coding standard, which explicitly taught switching between two different coding tables based on the value of the previous_level—the level value of a preceding coefficient—to achieve better compression.
    • Motivation to Combine: A POSITA would combine these complementary references to pursue their shared goal of improved coding efficiency. Petitioner contended that a POSITA would recognize VCEG-L28's previous_level criterion as a known technique to improve an existing system. Applying this specific, data-dependent switching logic to Tsai's more general two-context framework was presented as a predictable design choice to enhance compression performance by better adapting to local data statistics.
    • Expectation of Success: A POSITA would have had a high expectation of success because Tsai's system, which already employed a two-table/two-context architecture (e.g., Symbol Map 1 and Symbol Map 2), was structurally well-suited to incorporate the specific two-table switching logic taught by VCEG-L28.
    • Key Aspects: The core of this argument is that VCEG-L28 provides a specific, data-driven rule for switching contexts that was a known, efficiency-improving technique readily applicable to Tsai's more general context-based coding framework.

Ground 2: Obviousness over AAPA and Savatier - Claims 1-9, 18-26, 35, 37, and 39 are obvious over AAPA in view of Savatier.

  • Prior Art Relied Upon: Applicant Admitted Prior Art (AAPA) from the ’701 patent's specification and Savatier (Patent 5,400,075).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that the AAPA, describing the then-current H.26L video coding standard, disclosed the foundational elements of the challenged claims, including a CABAC encoder that performs block-based processing, transform coding, and context assignment for binarized run/level values based on factors like bin position. This baseline system was allegedly rendered obvious by Savatier, which taught an adaptive Variable-Length Coding (VLC) system. Savatier's system dynamically selected between two VLC tables based on the characteristics of the immediately preceding codeword, specifically its RUN and LEVEL values. Petitioner argued that incorporating Savatier's teaching of making the coding choice for a current symbol dependent on the LEVEL of the prior symbol into the AAPA's CABAC framework would meet the claim limitations.
    • Motivation to Combine: A POSITA would have been motivated to integrate Savatier's adaptive selection method into the H.26L system described in the AAPA to realize known benefits. Savatier explicitly stated that switching tables based on prior run/level data "tends to enhance overall system coding efficiency," providing a clear reason to apply this known technique to the well-known H.26L system.
    • Expectation of Success: A POSITA would have reasonably expected success because the H.26L framework is already a statistically adaptive coding scheme. Savatier's method of using a prior codeword's properties to inform the coding of a subsequent codeword was a compatible and logical extension of the adaptive principles already present in the H.26L standard.
    • Key Aspects: This ground leverages the patentee's own description of the H.26L standard as the baseline system, arguing it was an obvious step to incorporate Savatier's well-understood method of adaptive table selection based on immediately preceding data.

  • Additional Grounds: Petitioner asserted further obviousness challenges, including: (1) combining Tsai, VCEG-L28, and VCEG-L13 (a proposal on adaptive codes for H.26L) for claims 15-16 and 32-33, which involve specific binarization and context modeling for run values; and (2) combining the AAPA with VCEG-L13 for claims 10-17, 27-34, 36, 38, and 40 to argue that making run value coding dependent on the level value was obvious.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under the Fintiv factors is unwarranted. The parallel district court litigation has no set schedule, and its expected trial date of July 2026 is anticipated to occur after the statutory deadline for a Final Written Decision (FWD) in this IPR, which is likely March 2026.
  • Petitioner also contended that denial under 35 U.S.C. §325(d) is inappropriate because the primary prior art references asserted in the petition—Tsai, VCEG-L28, Savatier, and VCEG-L13—were not considered by the patent examiner during the original prosecution of the ’701 patent.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review (IPR) and the cancellation of claims 1-40 of Patent 6,856,701 as unpatentable.