DCT

6:20-cv-00490

WSOU Investments LLC v. ZTE Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:20-cv-00490, W.D. Tex., 11/06/2020
  • Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because Defendants have committed acts of infringement in the district and maintain regular and established places of business, including offices and a research-and-development center in Austin, Texas.
  • Core Dispute: Plaintiff alleges that Defendant’s smartphones supporting modern video codecs, such as AV1, infringe a patent related to video compression methods that use non-displayable virtual reference data.
  • Technical Context: The technology concerns advanced video compression techniques designed to improve coding efficiency for applications like video streaming, which is critical for delivering high-quality video over networks with limited bandwidth.
  • Key Procedural History: The complaint was filed on November 6, 2020. Subsequent to the filing, the asserted patent was subject to two Inter Partes Review (IPR) proceedings before the Patent Trial and Appeal Board. IPR2021-00378 resulted in the cancellation of claims 9-11 and 23-25. IPR2021-00696 resulted in the cancellation of claims 1-8, 12-22, and 26-28. Together, these IPRs have resulted in the cancellation of all claims of the asserted '960 patent.

Case Timeline

Date Event
2008-11-12 U.S. Patent No. 8,179,960 Priority Date
2012-05-15 U.S. Patent No. 8,179,960 Issued
2019-10-15 Defendant announces Blade Vantage 2 Accused Product
2019-11-20 Defendant advertises Axon 10 Pro Accused Product
2020-11-06 Complaint Filed
2020-12-30 IPR2021-00378 Filed against '960 Patent
2021-03-26 IPR2021-00696 Filed against '960 Patent
2022-12-16 IPR Certificate Issued Cancelling Claims 9-11, 23-25
2023-01-24 IPR Certificate Issued Cancelling Claims 1-8, 12-22, 26-28

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 8,179,960 - "METHOD AND APPARATUS FOR PERFORMING VIDEO CODING AND DECODING WITH USE OF VIRTUAL REFERENCE DATA"

  • Patent Identification: U.S. Patent No. 8,179,960, "METHOD AND APPARATUS FOR PERFORMING VIDEO CODING AND DECODING WITH USE OF VIRTUAL REFERENCE DATA," issued May 15, 2012.

The Invention Explained

  • Problem Addressed: The patent describes limitations in conventional block-based video codecs, noting that their efficiency is constrained because reference blocks used for prediction must be based on an actual part of a previously displayed video frame. (’960 Patent, col. 1:63-col. 2:4).
  • The Patented Solution: The invention introduces the concept of "virtual reference data," which is defined as a block of pixels used as a reference for encoding or decoding but which "does not comprise or represent any portion of the actual video sequence to be displayed." (’960 Patent, Abstract; col. 2:19-25). A coder can generate this optimized virtual data, encode it, and transmit it along with an indication that it is not for display. A decoder then uses this virtual data to more efficiently reconstruct the actual video frames that are intended for display. (’960 Patent, col. 2:29-54).
  • Technical Importance: This method allows for the creation of reference data that is algorithmically optimized for compression, rather than being limited to using actual, previously-seen frames, which can lead to significant data compression gains. (’960 Patent, col. 2:15-18).

Key Claims at a Glance

  • The complaint asserts at least independent claim 9. (’960 Patent, Compl. ¶45).
  • The essential elements of Claim 9, a decoding method, are:
    • Identifying in an encoded video signal an "indication" that "encoded virtual reference data" has been incorporated, where this virtual data does not represent any portion of any individual frame to be displayed.
    • Decoding the incorporated "encoded virtual reference data."
    • Decoding one or more displayable portions of the original video signal, where these portions are "based on and specifically reference a portion of said encoded virtual reference data."
  • The prayer for relief more broadly seeks judgment on "one or more claims" of the patent. (Compl. p. 18).

III. The Accused Instrumentality

Product Identification

  • The complaint identifies "video display products, including phones," with a specific focus on the ZTE Axon 10 Pro. (Compl. ¶¶26-27).

Functionality and Market Context

  • The infringement allegation centers on the accused products running the Android 10 operating system, which supports modern video codecs such as AV1 and its predecessors, VP9/VP8. (Compl. ¶¶28-29). The complaint alleges that the functionality of these codecs, particularly AV1, aligns with the patented method. (Compl. ¶29). Specifically, it is alleged that the codecs generate and use special non-displayable reference frames, such as "Alternate Reference Frames" (ALTREF), for the sole purpose of improving compression of the frames that are actually displayed. (Compl. ¶¶32, 34, 40). A screenshot from a technical paper included in the complaint describes AV1's use of an "ALTREF(temporal filtered future) frame." (Compl. ¶32, p. 9). These codecs are fundamental to streaming high-quality video on mobile devices. (Compl. ¶29).

IV. Analysis of Infringement Allegations

'960 Patent Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
A method for decoding an encoded video signal...comprising the steps of: identifying in said encoded video signal an indication that encoded virtual reference data has been incorporated therein, wherein said encoded virtual reference data does not represent any portion of any individual frame...which is to be displayed... The complaint alleges the AV1 codec used by the Accused Products incorporates non-displayable "Alternate Reference Frames" (ALTREF) into the encoded video signal. An "invisible flag" allegedly serves as the "indication" that informs the decoder that this frame is not for display. ¶¶39, 41 col. 13:11-18
decoding, using a processor, from said encoded video signal said encoded virtual reference data incorporated therein; and It is alleged that the decoder in the Accused Products decodes the ALTREF frames. A diagram provided in the complaint illustrates a decoding order where the ALTREF frame is decoded before the displayable frames that depend on it. This diagram depicts the "ALTREF" frame as part of the decoding sequence. (Compl. ¶38, p. 13). ¶¶38, 44 col. 13:19-22
decoding, using a processor, from said encoded video signal one or more encoded portions of the original video signal which are to be displayed...wherein said encoded portions...are based on and specifically reference a portion of said encoded virtual reference data. The complaint alleges that the displayable video frames are decoded using the previously decoded ALTREF frames as a reference. The ALTREF frames are described as being "utilized for the encoding of other frames but are not to be displayed in the output of the video signal," implying a reference relationship. ¶¶40, 43, 44 col. 13:23-29
  • Identified Points of Contention:
    • Scope Questions: The patent requires "virtual reference data" to not "represent any portion of the actual video sequence to be displayed." (’960 Patent, col. 2:23-25). The complaint describes the accused ALTREF as a "no-show reference obtained through temporal filtering of a look-ahead frame." (Compl. ¶40). This raises the question of whether a filtered version of an actual future frame still "represents" a portion of the video sequence, which could be a central point of claim construction and infringement analysis.
    • Technical Questions: What is the specific mechanism of the "indication" required by claim 9? The complaint alleges an "invisible flag" (Compl. ¶41), but it is unclear if this is a distinct data bit or if the indication is inherent in the frame being designated as an ALTREF type in the bitstream header. The evidence required to prove the "identifying" step will depend on this technical detail.

V. Key Claim Terms for Construction

  • The Term: "virtual reference data"

    • Context and Importance: This term is the core of the invention. The infringement case hinges on whether the "Alternate Reference Frames" (ALTREF) used in the accused AV1 codec fall within this definition.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent defines the term as data that "does not comprise or represent any portion of the actual video sequence to be displayed." (’960 Patent, col. 2:23-25). Plaintiff may argue that "represent" implies a direct pixel-for-pixel copy, and that any data that has been algorithmically generated or filtered, like an ALTREF, no longer "represents" the original source frame.
      • Evidence for a Narrower Interpretation: The abstract and summary suggest the data is "generated by the video coder based on the blocks being predicted but not based on any actual blocks in any of the actual video frames." (’960 Patent, Abstract). Defendant may argue this implies the data must be synthesized and not merely a filtered or modified version of an existing future frame, as the ALTREF is alleged to be.

  • The Term: "indication"

    • Context and Importance: Claim 9 requires the decoder to "identify" an "indication" that virtual reference data is present. Practitioners may focus on this term because the nature of this "indication" will determine what evidence is needed to prove infringement of this step.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent specification refers to writing a "reference-only frame header" (see FIG. 1, step 101) and an "indication that said encoded virtual reference data incorporated therein comprises data which does not represent any portion of any individual frame" (’960 Patent, col. 2:40-44). This could support an interpretation where the frame type itself, as defined in a header, serves as the "indication."
      • Evidence for a Narrower Interpretation: The act of "identifying" an "indication" could be argued to require a discrete flag or signal separate from the general frame-type data, consistent with the complaint's allegation of an "invisible flag." (Compl. ¶41). A defendant might argue that simply processing a frame known to be an ALTREF type does not constitute "identifying" a separate "indication."

VI. Other Allegations

  • Indirect Infringement: The complaint alleges inducement based on Defendant’s advertising, product descriptions, and operating manuals that allegedly instruct on the use of the infringing functionality. (Compl. ¶48).
  • Willful Infringement: The complaint alleges willful infringement based on knowledge of the '960 patent obtained "since at least the date of service of this Complaint," which constitutes an allegation of post-suit willfulness. (Compl. ¶47).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A dispositive threshold issue will be one of case viability: given that all claims of the '960 patent were cancelled in IPR proceedings that concluded after the complaint was filed, on what legal grounds can the lawsuit proceed? The patent is, for all practical purposes, no longer enforceable.
  • Assuming the case were not moot, a core issue would be one of definitional scope: can the term "virtual reference data", which the patent suggests is generated without being based on any actual blocks, be construed to cover the accused "ALTREF" frames, which the complaint itself describes as being derived from "temporal filtering of a look-ahead frame"?
  • Finally, a key evidentiary question would be one of functional mapping: does the complaint provide sufficient factual support to show that the accused codecs contain a specific "indication" that is "identified" by the decoder, as required by the claim, or is the non-display of ALTREF frames simply an inherent property of their type, without a discrete "indication" being identified?