PTAB

IPR2019-00806

Unified Patents Inc. v. Velos Media, LLC

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1. Case Identification

2. Patent Overview

  • Title: Context Adaptive Binary Arithmetic Coding
  • Brief Description: The ’241 patent relates to a system for video encoding and decoding using Context-Adaptive Binary Arithmetic Coding (CABAC). The alleged invention involves using the same "context set" for coding both the Cb (chroma blue) and Cr (chroma red) chroma coded block flags, with the specific context selected from the set based on the transform depth of an associated transform unit.

3. Grounds for Unpatentability

Ground 1: Claims 1 and 2 are obvious over Sasai in view of Kao.

  • Prior Art Relied Upon: Sasai (Application # 2013/0003861) and Kao (Application # 2009/0196355).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sasai, an analogous art concerning video decoding with CABAC, discloses the key limitations of independent claim 1. Sasai teaches determining a context for Cb (cbf_cb) and Cr (cbf_cr) chroma coded block flags based on a "hierarchical depth," which Petitioner equated to the claimed "transform depth." Critically, Petitioner asserted that Sasai discloses using the same context set (comprising contexts 0, 1, 2, and 3) for decoding both the Cb and Cr flags. To the extent Sasai was found not to explicitly teach using the same selected context for both flags (as opposed to just the same set), Petitioner contended that Kao supplied this teaching. Kao was cited for its disclosure of using the "same context" to decode consecutive data bins in a CABAC system, a known technique for improving compression. Claim 2, which depends on claim 1, adds the decoding of non-zero transform coefficients from the Cb and Cr transform blocks, a function Petitioner argued is also disclosed by Sasai's decoding unit.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine Sasai and Kao to achieve predictable improvements in video decoding. Sasai recognized the need for improved decoding with reduced memory usage, a known benefit of efficient context selection. Kao taught a specific, known method for improving efficiency in CABAC decoding—using the same context for multiple data elements. A POSA would have found it obvious to apply Kao's established technique to Sasai's system to achieve the desired goals of bit-rate savings and improved speed.
    • Expectation of Success: A POSA would have had a reasonable expectation of success in combining the references. The combination involved a simple, routine modification to Sasai's decoding software to implement the context selection strategy taught by Kao. Given that Sasai’s system already presented a finite, predictable set of context selection options, implementing one of those known options as taught by Kao would have been straightforward and yielded predictable results.

Ground 2: Claims 5-6 and 9-13 are obvious over Sasai.

  • Prior Art Relied Upon: Sasai (Application # 2013/0003861).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sasai alone discloses all limitations of the remaining apparatus and method claims.
      • Independent Claim 5 (Apparatus): This claim mirrors the method of claim 1 in an apparatus format. Petitioner mapped this to Sasai's disclosure of devices like a cellular phone and a television, which function as an "apparatus for decoding video data" and include a memory and a processor. Petitioner asserted Sasai's processor is configured to perform the key claimed steps: selecting a context based on transform depth and, crucially, using the same context set to entropy decode both the Cb and Cr chroma coded block flags.
      • Independent Claim 12 (Encoding Method): This claim recites the encoding-side counterpart to the decoding method of claim 1. Petitioner argued this was obvious over Sasai, which discloses an encoder that logically mirrors its decoder, including using the same context model set for both encoding and decoding operations.
      • Dependent Claims: Petitioner mapped the limitations of dependent claims 6 and 9-11 to inherent or explicit features of the devices disclosed in Sasai. These included decoding non-zero transform coefficients (Claim 6), incorporating a display device (Claim 9), specifying the apparatus as a smartphone or television (Claim 10), and including a receiver for a video bitstream (Claim 11). Claim 13, dependent on the encoding method of claim 12, adds the encoding of non-zero transform coefficients, which Petitioner asserted is a fundamental part of the encoding process described in Sasai.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1, 2, 5, 6, and 9-13 of Patent 9,277,241 as unpatentable.