Sling TV L.L.C. v. Uniloc 2017 LLC

1. Case Identification

• Case #: IPR2019-01391
• Patent #: 6,895,118
• Filed: August 12, 2019
• Petitioner(s): Sling TV L.L.C.
• Patent Owner(s): Uniloc 2017 LLC
• Challenged Claims: 1-6 and 9

2. Patent Overview

• Title: Method of Encoding a Digital Image
• Brief Description: The ’118 patent discloses a method for video encoding that intentionally drops macroblocks from a data stream to reduce the bitrate. The method then inserts resynchronization markers to trigger standard error concealment mechanisms in decoders, enabling the reconstruction of the dropped macroblocks.

3. Grounds for Unpatentability

Ground 1: Obviousness over Zeng and Brailean - Claims 1-5 and 9 are obvious over Zeng in view of Brailean.

• Prior Art Relied Upon: Zeng (a 1999 IEEE publication) and Brailean (Patent 6,498,865).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the ’118 patent itself admits Zeng teaches the core method of excluding macroblocks based on their reconstructability via error concealment. Brailean was asserted to teach the improvement of inserting "resynchronization tags" into a bitstream after the intentional introduction of packet losses (i.e., dropped blocks) to enhance error resilience. Petitioner contended that combining Zeng's block-dropping with Brailean's subsequent insertion of resynchronization markers teaches every limitation of independent claim 1 and the corresponding dependent claims.
  • Motivation to Combine: A POSITA would combine Zeng with Brailean to improve the error resilience of Zeng’s bitrate reduction technique. Petitioner argued that dropping blocks per Zeng necessarily introduces errors that can propagate, and Brailean explicitly teaches inserting resynchronization markers as a solution to remedy such errors and improve video quality, particularly within standards-compliant frameworks like MPEG-4.
  • Expectation of Success: A POSITA would have an expectation of success because both references operate within standard video coding principles. Brailean expressly discloses that its technique is compatible with existing visual coding standards, including MPEG-4, and that the insertion of resync markers successfully mitigates errors in a robust decoder.

Ground 2: Obviousness over Zeng, Brailean, and Yoo - Claim 6 is obvious over Zeng in view of Brailean and Yoo.

• Prior Art Relied Upon: Zeng, Brailean, and Yoo (Patent 6,445,742).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built on the Zeng/Brailean combination to address the specific spatial limitation of claim 6, which requires the resynchronization marker to be present "at the point where macroblocks are not coded." While Brailean teaches inserting markers after exclusion, Petitioner asserted that Yoo teaches inserting resynchronization markers based on whether macroblocks are "skipped." Yoo was argued to teach that placing the marker precisely at the point of exclusion is the most effective way to prevent error propagation and minimize decoding errors.
  • Motivation to Combine: A POSITA would be motivated to incorporate Yoo’s teaching to optimize the placement of the resynchronization marker from the Zeng/Brailean combination. Yoo directly addresses the problem of error propagation by teaching precise marker placement relative to skipped blocks, which would be seen as a logical and beneficial improvement to a system that intentionally drops blocks.
  • Expectation of Success: The combination involves applying known error-handling techniques to a known bitrate reduction method within standard video codecs. Petitioner asserted this would be a predictable optimization of error handling with a high likelihood of success.

Ground 3: Anticipation by Brailean - Claim 6 is anticipated by Brailean under Patent Owner's apparent construction.

• Prior Art Relied Upon: Brailean (Patent 6,498,865).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner presented this ground as contingent on a broad construction of "resynchronization marker," which it alleged the Patent Owner advanced in parallel district court litigation. Under this broad construction, a simple flag indicating a macroblock is uncoded would qualify as a "resynchronization marker." Petitioner argued that Brailean discloses "replacement tags"—short codewords that indicate a block is not coded—which are inserted "at the point" where bits are dropped. Petitioner contended these tags are akin to the "uncoded" flag in MPEG-4 and would therefore anticipate claim 6 if the term "resynchronization marker" were construed so broadly.

4. Key Claim Construction Positions

• "after the exclusion of one or more macroblocks" (Claims 1, 4): Petitioner argued this phrase requires a temporal relationship, meaning the marker insertion step occurs subsequent in time to the macroblock exclusion step during the encoding process. This construction was presented to distinguish these claims from the more specific spatial relationship ("at the point") required by claim 6, making claims 1 and 4 broader.
• "resynchronization marker" (Claims 1, 4, 6): Petitioner proposed this term means a predetermined plurality of bits (e.g., at least 17 bits per the MPEG-4 standard) with sufficient length and uniqueness to be located by a decoder scanning the bitstream without context. This construction was argued to be critical for distinguishing a true marker from a simple 1-bit "uncoded" or "skip" flag, which Petitioner noted the ’118 patent itself disclaims as being the invention.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d) because the primary prior art references, Brailean and Yoo, were not considered by the Examiner during the original prosecution. The petition asserted that although related foreign articles were submitted in an Information Disclosure Statement, the record shows they were not substantively reviewed. Furthermore, because the application was allowed without any prior art rejections, Petitioner contended its invalidity grounds were being raised for the first time.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-6 and 9 of Patent 6,895,118 as unpatentable.