Sling TV LLC 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 Coding a Digital Image
• Brief Description: The ’118 patent discloses a method for encoding digital video by intentionally dropping or excluding macroblocks from a binary data stream to reduce the bitrate. The method then inserts resynchronization markers, leveraging error concealment mechanisms in standard-compliant decoders to reconstruct the excluded 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 admits Zeng taught the core concept of dropping macroblocks based on an estimation of their capacity to be reconstructed via error concealment, thus meeting the "estimation step" and "decision step" limitations of independent claim 1. Brailean was asserted to teach the final element: inserting resynchronization markers into the bitstream after the intentional introduction of packet losses (i.e., after dropping data) to improve error resilience and localize errors. Dependent claims 2 and 3, related to bitrate reduction evaluation, were also argued to be taught by Zeng’s rate-distortion optimal strategy.
  • Motivation to Combine: A POSITA applying Zeng’s bitrate reduction technique would encounter the known problem of error propagation, as intentionally dropping macroblocks would appear as an error to a standard decoder. Petitioner argued a POSITA would be motivated to look for solutions and find Brailean, which explicitly addresses improving "error resilience" in bitstreams (including MPEG-4) where packet losses have been intentionally introduced. Combining Brailean’s solution with Zeng’s technique was presented as a straightforward application to improve the quality and robustness of Zeng's method.
  • Expectation of Success: Both Zeng and Brailean operate within the known field of video compression and address standards like MPEG. Brailean expressly taught that its technique is compatible with MPEG-4 syntax elements, including resynchronization markers, providing a clear path and a high expectation of success for the combination.

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 (a 1999 IEEE publication), Brailean (Patent 6,498,865), and Yoo (Patent 6,445,742).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination of Zeng and Brailean to address the specific limitation in claim 6 requiring a resynchronization marker to be "present in the binary data stream at the point where macroblocks are not coded." While the Zeng-Brailean combination taught inserting a marker after exclusion, Petitioner argued Yoo provided the explicit teaching for placing it precisely at the point of exclusion. Yoo taught inserting resynchronization markers into a bitstream at predetermined positions based on whether macroblocks are "skipped" to prevent error propagation.
  • Motivation to Combine: A POSITA implementing the Zeng-Brailean combination would seek to optimize marker placement to minimize data loss between the dropped block and the next marker. Petitioner asserted that Yoo directly addressed this problem, teaching that placing a marker at the point of a skipped block is advantageous for preventing error propagation. This would improve the overall quality and efficiency of the system, furthering the goals of both Zeng (bitrate reduction) and Brailean (error robustness).
  • Expectation of Success: The proposed modification was described as a simple application of Yoo’s teachings on marker placement to the established Zeng-Brailean combination. As all three references concerned the same technical field of video bitstream processing, a POSITA would have a high expectation of successfully implementing this optimization.

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

• Prior Art Relied Upon: Brailean (Patent 6,498,865).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented as an alternative based on a broader construction of "resynchronization marker" that Petitioner alleged the Patent Owner was asserting in district court litigation. If the term is construed to cover a simple flag indicating a macroblock is uncoded (akin to MPEG-4's "uncoded" flag), Petitioner argued Brailean anticipated claim 6. Brailean disclosed replacing dropped bits with "replacement tags," described as "short code words designed to preserve timing and spatial information." These tags, which indicate a block is "NOT CODED," were asserted to be present "at the point where macroblocks are not coded" and would therefore meet all limitations of claim 6 under this broader construction.

4. Key Claim Construction Positions

• "after the exclusion of one or more macroblocks" (Claims 1 & 4): Petitioner argued this phrase connoted a temporal relationship, meaning the insertion step must occur in time after the exclusion step is performed by the encoder. It was argued this construction does not require a specific spatial relationship in the resulting bitstream (e.g., the marker replacing the excluded block), which is a limitation recited separately in claim 6.
• "resynchronization marker" (Claims 1, 4, & 6): Petitioner proposed this term meant "a predetermined plurality of bits... which has a sufficient length such that the decoder can locate them in the event of an error." This construction was intended to distinguish a true resynchronization marker from a simple, single-bit "uncoded" or "skipped" flag, a distinction Petitioner argued was acknowledged in the ’118 patent specification itself.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under 35 U.S.C. §325(d), asserting that the petition raised new arguments not considered during prosecution. Although Zeng was cited on the face of the ’118 patent, it was never the basis for a rejection. The key secondary references, Brailean and Yoo, were not considered by the Examiner during prosecution. Therefore, Petitioner contended that the asserted grounds were not cumulative and that instituting review would not be redundant of the USPTO's prior work.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-6 and 9 of the ’118 patent as unpatentable.