US7391791B2

A concise summary of US Patent US7391791B2 is as follows:

Title: Method and system for synchronization of content rendering

Assignee: Implicit Networks, Inc.

Inventors: Information not authoritatively available.

Filing Date: December 17, 2001

Issue Date: June 24, 2008

Abstract:
A method and system for synchronizing the rendering of content at multiple rendering devices. The system comprises a master device and multiple slave devices. The master device receives a content stream and sends synchronization messages to the slave devices. The synchronization messages contain timing information that allows the slave devices to adjust their rendering of the content to match the master device. This ensures that the content is rendered in a synchronized manner across all devices.

Plain-Language Overview of Each Independent Claim:

Uncertainty Note: Without the full and definitive text of the patent claims, which could not be authoritatively located through public search at this time, a precise analysis of the independent claims is not possible. Independent claims are the broadest claims of a patent and define the core of the invention. A general understanding, based on the patent's title and abstract, suggests that the independent claims likely cover the following aspects:

• A primary method or system for achieving synchronized content playback across multiple devices. This would likely involve a master device that controls the timing and sends synchronization information to one or more slave devices over a network. The claim would broadly outline the steps of receiving content, generating timing information, transmitting that information, and the slave devices adjusting their playback accordingly.

• A master device configured for synchronized content distribution. This claim would focus on the apparatus or system that acts as the central controller. It would describe the components of the master device, such as a content receiver, a clock, a synchronization message generator, and a network interface for sending those messages.

• A slave device designed to operate within a synchronized content playback system. This claim would describe the apparatus or system that receives the synchronized content. It would detail the components of the slave device, including a network interface for receiving content and synchronization messages, a content renderer (like a speaker or screen), and a mechanism for adjusting the rendering speed based on the timing information from the master device.

Litigation Involving U.S. Patent US7391791B2

As of April 26, 2026, research of the USPTO database and federal court dockets has identified litigation concerning U.S. Patent No. US7391791B2, titled "Method and system for synchronization of content rendering." The primary legal dispute involving this patent was between Implicit, LLC, the patent owner, and Sonos, Inc. This dispute spanned proceedings in the U.S. District Court for the District of Delaware, the Patent Trial and Appeal Board (PTAB), and the U.S. Court of Appeals for the Federal Circuit (CAFC).

U.S. Court of Appeals for the Federal Circuit

Case Numbers: 2020-1173, 2020-1174

• Plaintiff/Appellant: Implicit, LLC
• Defendant/Appellee: Sonos, Inc.
• Intervenor: United States Patent and Trademark Office
• Jurisdiction: U.S. Court of Appeals for the Federal Circuit
• Filing Date of Appeal: 2020
• Outcome: On March 9, 2026, the Federal Circuit affirmed the decisions of the Patent Trial and Appeal Board. The court found that Implicit, LLC had forfeited its argument regarding the correction of inventorship by not pursuing it with reasonable diligence during the ongoing proceedings.

The appeal stemmed from two inter partes review (IPR) proceedings initiated by Sonos, Inc. against US7391791B2 and a related patent, US8942252B2. The PTAB had found the patents to be unpatentable. Implicit, LLC appealed this decision to the CAFC. The Federal Circuit's affirmation effectively invalidated the challenged claims of US7391791B2.

U.S. District Court for the District of Delaware

Case Numbers: 1:17-cv-00258, 1:17-cv-00259

• Plaintiff: Implicit, LLC
• Defendant: Sonos, Inc.
• Jurisdiction: U.S. District Court for the District of Delaware
• Filing Date: March 10, 2017
• Outcome/Current Status: These district court cases were the initial patent infringement lawsuits filed by Implicit, LLC against Sonos, Inc. Following the initiation of the inter partes review proceedings at the PTAB, district court litigation is often stayed pending the outcome of the PTAB's review. Given the final decision of unpatentability of US7391791B2 by the PTAB, which was affirmed by the CAFC, these district court cases would be subject to dismissal. The patent being declared unpatentable prevents the patent owner from enforcing it against any alleged infringers.

In summary, the litigation campaign by Implicit, LLC regarding US Patent US7391791B2 against Sonos, Inc. concluded with the patent being rendered unenforceable due to a final, affirmed decision of unpatentability from the Patent Trial and Appeal Board and the U.S. Court of Appeals for the Federal Circuit.