Prior art — US Patent US8942252B2

Analysis of Prior Art for U.S. Patent No. 8,942,252

An analysis of the prior art cited during the examination of U.S. Patent No. 8,942,252 reveals several key documents that were considered by the USPTO patent examiner. This analysis details the most relevant of these references and their potential impact on the patentability of the claims under 35 U.S.C. § 102, which pertains to novelty and anticipation. The following references were cited by the examiner or the applicant and are listed in the patent's file wrapper.

U.S. Patent No. 6,233,609 B1

Full Citation: US Patent 6,233,609 B1, "Method and apparatus for providing temporal synchronization of data streams in a networked computer system," assigned to Intel Corporation.
Publication/Filing Date: Published May 15, 2001; Filed June 30, 1998.
Brief Description: This patent describes a system for synchronizing multiple data streams (e.g., audio and video) in a networked environment. It introduces the concept of a "master" clock and "slave" clocks. The master transmits its clock value to the slaves, which then adjust their own clocks to match the master's. This is intended to ensure that the playback of different data streams remains synchronized over time. The system calculates the network latency to improve the accuracy of the synchronization.
Potential Anticipation of Claims: This reference appears to be highly relevant to the core concepts of US8942252B2.
- Claim 1: The '609 patent discloses a master device that renders a content stream and sends timing information to slave devices to enable synchronous rendering. This aligns with the limitations of claim 1 concerning a master rendering device sending master rendering times to a slave device for the purpose of synchronous rendering.
- Claim 11: From the slave device's perspective, the '609 patent describes receiving timing information from a master and adjusting its clock, and therefore its rendering, to maintain synchronization. This corresponds to the steps outlined in claim 11, where a slave device receives master rendering times and uses them to render a content stream synchronously.

U.S. Patent No. 6,487,219 B1

Full Citation: US Patent 6,487,219 B1, "System and method for time-synchronizing clients in a packet-based network," assigned to Sony Corporation.
Publication/Filing Date: Published November 26, 2002; Filed November 29, 1999.
Brief Description: This patent details a method for synchronizing the clocks of multiple client devices in a packet-based network. A "time master" client sends out synchronization packets containing its local time. Other "slave" clients receive these packets and adjust their local clocks based on the master's time and the network transit time of the packets. The goal is to provide a common time base for all clients, which can be used for synchronized events.
Potential Anticipation of Claims: This reference also discloses a master/slave synchronization architecture.
- Claim 1: The '219 patent's "time master" sending its local time to "slave" clients for synchronization purposes is analogous to the master rendering device in claim 1 sending its rendering times. The purpose of enabling synchronous operations is also present.
- Claim 11: The '219 patent describes slave clients receiving time information from a master and using it to adjust their own timing. This is fundamentally similar to the process described in claim 11 for a slave device to achieve synchronous rendering.

U.S. Patent No. 6,831,911 B1

Full Citation: US Patent 6,831,911 B1, "Method for synchronizing the rendering of media streams," assigned to Microsoft Corporation.
Publication/Filing Date: Published December 14, 2004; Filed December 29, 2000.
Brief Description: This patent focuses on synchronizing the rendering of media streams by using timestamps embedded within the streams. A "master stream" is designated, and its timestamps are used as a reference. "Slave streams" compare their own timestamps to the master's and adjust their rendering rate (e.g., by skipping or duplicating frames) to stay in sync. The patent also discusses a "smoothing" mechanism to avoid abrupt changes in playback.
Potential Anticipation of Claims: This reference is particularly relevant due to its mention of a "smoothing" function.
- Claim 1: The '911 patent discloses a master stream whose timing is used as a reference for slave streams, which aligns with the concept of a master rendering device sending rendering times as recited in claim 1.
- Claim 11: This patent's description of a slave device adjusting its rendering rate based on a comparison with a master stream's timing and the use of a "smoothing" mechanism to make these adjustments less jarring to the user strongly relates to the limitations of claim 11. Claim 11 specifically recites determining a "smoothed rendering time differential."

U.S. Patent No. 7,092,416 B2

Full Citation: US Patent 7,092,416 B2, "System and method for distributed media rendering synchronization," assigned to Hewlett-Packard Development Company, L.P.
Publication/Filing Date: Published August 15, 2006; Filed June 14, 2001.
Brief Description: This patent describes a system for synchronizing media rendering across multiple devices without relying on a single master clock. Instead, it uses a distributed approach where devices exchange timing information and collaboratively establish a common timeline. This can involve one device being dynamically selected as a temporary master. The system aims to compensate for clock drift between devices.
Potential Anticipation of Claims: While this patent describes a more distributed system, the underlying principles of exchanging timing information for synchronization are present.
- Claim 1 & 11: Although the '416 patent focuses on a distributed model, it still involves the fundamental concepts of devices sending and receiving timing information to synchronize media rendering. In scenarios where one device acts as a temporary master, its operation would be similar to the master/slave relationship described in claims 1 and 11. The core idea of adjusting rendering based on received timing information is a central theme.

Disclaimer

This analysis is based on the cited prior art found in the public record for US Patent US8942252B2. A definitive determination of anticipation would require a more detailed claim construction and legal analysis. The term "potential anticipation" is used to indicate that the cited references disclose subject matter that appears to read on the claims of the patent in question.