Hulu LLC v. DivX CF Investors LLC

1. Case Identification

• Case #: IPR2021-01418
• Patent #: 10,257,443
• Filed: September 3, 2021
• Petitioner(s): Hulu, LLC
• Patent Owner(s): DivX, LLC
• Challenged Claims: 1-2, 4, 7-8, 10, 13-16

2. Patent Overview

• Title: Multimedia Distribution System for Multimedia Files with Interleaved Media Chunks of Varying Types
• Brief Description: The ’443 patent discloses systems and methods for encrypting, encoding, decoding, and decrypting multimedia files, particularly for streaming. The invention involves a file structure with encoded video frames and metadata, allowing for the inclusion of Digital Rights Management (DRM) through partial encryption of video frames.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4, 7, 8, 10, 14, and 16 are obvious over Toma in view of Candelore-I and Candelore-II.

• Prior Art Relied Upon: Toma (WO 2004/0004334), Candelore-I (Application # 2003/0133570), and Candelore-II (Application # 2004/0049694).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Toma taught creating and playing back fragmented MP4 files for network distribution, including a file structure with interleaved header (moof) and media data (mdat) chunks. Candelore-I and Candelore-II collectively taught partial encryption of encoded video frames (e.g., using a "star pattern") and using DRM information, such as "video encryption pointers" with byte offsets, to identify the location and size of encrypted blocks within a frame. Petitioner asserted that placing Candelore's DRM pointers into Toma's moof header chunks to correspond with partially encrypted video data in the mdat chunks rendered the claims obvious.
  • Motivation to Combine: A POSITA would combine these references to protect the copyrighted video content distributed by Toma's streaming system from piracy, a well-known problem at the time. Applying Candelore's partial encryption techniques to Toma's MPEG-based system was a logical step to add security without the high overhead of full encryption.
  • Expectation of Success: Success was predictable because all references concerned techniques for modifying MPEG data for network distribution. The MP4 file format taught by Toma was known to be extensible, and combining it with Candelore's DRM methods was a straightforward modification to yield the predictable result of secure streaming.

Ground 2: Claims 4, 10, and 16 are obvious over Toma in combination with Candelore-I, Candelore-II, and Mowry.

• Prior Art Relied Upon: Toma (WO 2004/0004334), Candelore-I (Application # 2003/0133570), Candelore-II (Application # 2004/0049694), and Mowry (Application # 2004/0253942).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground added the teachings of Mowry to the combination in Ground 1 to explicitly address limitations requiring a "reference to a decryption key." Petitioner contended that Mowry disclosed a DRM system where a Uniform Resource Identifier (URI) located in a DRM package header serves as a reference that maps to a Content Encryption Key (CEK) used for decryption.
  • Motivation to Combine: A POSITA, having combined Toma and Candelore to create a partially encrypted streaming file, would be motivated to incorporate Mowry's method for referencing a decryption key. This would provide a complete and functional DRM system by enabling a decoder to retrieve the necessary key.
  • Expectation of Success: Integrating a key reference mechanism like Mowry's URI into the DRM chunk (moof box) of the base combination was a simple and predictable modification, as all references were directed to protecting and distributing multimedia files over a network.

Ground 3: Claims 1, 2, 4, 7, 8, 10, and 13-16 are obvious over Toma and Matsui in combination with Candelore-I and Candelore-II.

• Prior Art Relied Upon: Toma (WO 2004/0004334), Matsui (WO 03/101114), Candelore-I (Application # 2003/0133570), and Candelore-II (Application # 2004/0049694).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground added the teachings of Matsui to the base combination of Ground 1. Petitioner argued that Matsui taught an "index chunk" limitation by disclosing a Random Access ("RA") information table that could be added to a fragmented MP4 file. This RA table contained information on the starting positions of moof chunks and data, enabling quick random access playback.
  • Motivation to Combine: A POSITA would combine Matsui with the Toma/Candelore combination to improve performance. Toma acknowledged the problem of "poor data access efficiency during playback," and Matsui's RA table provided a known solution to enable faster random access. The shared inventors and similar fragmented MP4 technology between Toma and Matsui further motivated the combination.
  • Expectation of Success: A POSITA would expect success because both Toma and Matsui taught modifying standard MP4 files. Adding Matsui's RA table to the combined Toma/Candelore encrypted file structure was a compatible and predictable improvement to enhance playback functionality.
• Additional Grounds: Petitioner asserted an additional obviousness challenge (Ground IV) against claims 4, 10, and 16 based on the combination of all prior art references (Toma, Matsui, Candelore-I, Candelore-II, and Mowry), relying on similar combination rationales.

4. Key Technical Contentions (Beyond Claim Construction)

• Contested Priority Date: A central contention of the petition was that the ’443 patent was not entitled to its claimed priority date of December 8, 2003. Petitioner argued that the parent [’809](https://ai-lab.exparte.com/case/ptab/IPR2021-01418/doc/1023) application lacked written description support for two key limitations introduced later: "partial encryption of an encoded frame" and a "network interface." This alleged lack of support would make the effective filing date December 8, 2004, rendering Toma (published January 8, 2004) available as prior art under 35 U.S.C. §102(a).

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under Fintiv would be inappropriate for several reasons.
  • Petitioner stipulated that, if the IPR were instituted, it would not advance the same grounds or grounds that reasonably could have been raised in the co-pending district court proceeding.
  • The petition was filed well before the one-year statutory bar, the co-pending litigation was in its earliest stages with no significant investment of resources, and the district court trial date was uncertain.
  • The petition presented strong merits, and the specific prior art combinations had not been considered during the original prosecution.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-2, 4, 7-8, 10, and 13-16 of the ’443 patent as unpatentable.