Prior art

The following analysis identifies potential prior art for US Patent 8542705, titled "Key frame detection and synchronization," based on the patent's own citations. The priority date for US8542705 is January 23, 2007.

US Patent 8542705: Core Innovation

US Patent 8542705 describes a streaming server that efficiently provides media streams to client devices by identifying key frames. Upon receiving a connection request (e.g., a channel change), the server provides the earliest available key frame of the requested stream, skipping any preceding predictive frames. This aims to reduce delay and improve user experience by ensuring the client receives a displayable frame immediately. Claims 1, 8, and 15 (method, system, and non-transitory computer readable medium, respectively) all center around this mechanism, including steps for identifying key frames (e.g., by GOP size, frame size, partial decoding) and buffering media streams on a per-GOP basis.

Prior Art Analysis (Cited Patents)

For each cited patent, a brief description and an assessment of its potential to anticipate the claims of US8542705 under 35 U.S.C. § 102 are provided. All cited patents have a priority or publication date before January 23, 2007, making them potential prior art.

1. US6023553A: Method and apparatus for achieving video data reduction through the use of re-encoding

   • Full Citation: US6023553A, Hitachi America, Ltd., "Method and apparatus for achieving video data reduction through the use of re-encoding," published February 8, 2000.
   • Publication/Filing Date: Priority date: January 13, 1993; Publication date: February 8, 2000.
   • Brief Description: This patent generally relates to video data compression and re-encoding techniques, focusing on reducing data size, potentially by optimizing the use of different frame types (I, P, B frames).
   • Potential Anticipation (35 U.S.C. § 102): This patent appears to address video encoding efficiency rather than the specific problem of starting a stream with a key frame upon a client request from a streaming server's buffer. While it deals with video frames, it likely does not disclose the unique combination of features in claim 1, such as buffering on a per-GOP basis, identifying a next available key frame in response to a channel change request, and explicitly not transmitting predictive frames at the beginning of the request. Therefore, it is unlikely to anticipate Claim 1 directly, though it provides context on video encoding techniques.

2. US20030005455A1: Aggregation of streaming media to improve network performance

   • Full Citation: US20030005455A1, Bowers J. Rob, "Aggregation of streaming media to improve network performance," published January 2, 2003.
   • Publication/Filing Date: Priority date: June 29, 2001; Publication date: January 2, 2003.
   • Brief Description: This application generally discusses improving network performance for streaming media, possibly through aggregation or efficient delivery mechanisms.
   • Potential Anticipation (35 U.S.C. § 102): This reference is broad and focuses on network performance improvement, which could involve various techniques. It is not clear from the title or general description if it specifically discloses identifying key frames in buffers and selectively transmitting them to new clients on connection requests while explicitly omitting predictive frames. Thus, it is unlikely to anticipate Claim 1, particularly the "identifying a next available key frame" and "no predictive frames are transmitted" limitations.

3. EP1523190A1: Fast channel change

   • Full Citation: EP1523190A1, Microsoft Corporation, "Fast channel change," published April 13, 2005.
   • Publication/Filing Date: Priority date: October 10, 2003; Publication date: April 13, 2005.
   • Brief Description: This European patent application specifically addresses "fast channel change" in media delivery systems. This is directly relevant to the problem US8542705 aims to solve. It likely involves mechanisms to reduce the delay experienced when switching channels.
   • Potential Anticipation (35 U.S.C. § 102): This patent is highly relevant. Fast channel change mechanisms often rely on sending an I-frame or a point of synchronization to the client quickly. It could potentially anticipate Claim 1, especially the core idea of responding to a channel change request by providing a key frame. The extent of anticipation would depend on whether it discloses the specific details of "determining positions of a plurality of key frames... by determining a GOP size N and identifying Nth frames following the first key frame as subsequent key frames," buffering on a "per GOP basis," and explicitly stating "no predictive frames are transmitted at the beginning of the channel change request." If it teaches sending the earliest available key frame and explicitly skipping preceding predictive frames, it would anticipate key aspects of Claim 1. Further review of its claims and detailed description would be necessary for a definitive conclusion, but it certainly appears to address the same problem space and a similar solution.

4. US20050081244A1: Fast channel change

   • Full Citation: US20050081244A1, Barrett Peter T., "Fast channel change," published April 14, 2005.
   • Publication/Filing Date: Priority date: October 10, 2003; Publication date: April 14, 2005.
   • Brief Description: This US patent application also explicitly addresses "fast channel change," indicating a focus on reducing latency during channel switching in media systems. It shares the same priority date as EP1523190A1, suggesting it might be a related or equivalent filing.
   • Potential Anticipation (35 U.S.C. § 102): Similar to EP1523190A1, this is a highly relevant reference. Given the identical priority date, it likely discloses similar concepts for achieving fast channel changes. If it teaches identifying key frames in a buffer and selectively transmitting the earliest available key frame upon a channel change request, while ensuring no predictive frames are transmitted initially, it could anticipate Claim 1. Detailed analysis of its specification would be required. It potentially anticipates Claim 1 and its dependent claims related to faster channel switching (e.g., Claim 7).

5. US20050190781A1: Media stream splicer

   • Full Citation: US20050190781A1, Microsoft Corporation, "Media stream splicer," published September 1, 2005.
   • Publication/Filing Date: Priority date: February 27, 2004; Publication date: September 1, 2005.
   • Brief Description: This application describes a media stream splicer, which is a component used to combine or insert different media segments into a stream, such as for advertisement insertion or personalized content.
   • Potential Anticipation (35 U.S.C. § 102): While related to media streams, a media stream splicer primarily deals with modifying the content of a stream, not necessarily with the initial synchronization for a new client connection. Although splicing often happens at key frame boundaries, the core problem and solution in US8542705 (providing the earliest available key frame for a new connection) are distinct. It's unlikely to anticipate Claim 1 directly, as it focuses on splicing operations rather than initial stream delivery optimization for new connections.

6. WO2006041784A2: Minimizing channel change time for IP video

   • Full Citation: WO2006041784A2, Wave7 Optics, Inc., "Minimizing channel change time for IP video," published April 20, 2006.
   • Publication/Filing Date: Priority date: October 4, 2004; Publication date: April 20, 2006.
   • Brief Description: This international application explicitly targets "minimizing channel change time for IP video," indicating a direct relevance to the problem addressed by US8542705 in the context of IP video delivery.
   • Potential Anticipation (35 U.S.C. § 102): This reference is very highly relevant due to its explicit focus on minimizing channel change time for IP video. It is highly probable that it discloses mechanisms involving key frames to achieve this. If it teaches identifying key frames in buffered media streams and providing the earliest one to a client upon a channel change request, while deliberately omitting preceding predictive frames, it would significantly anticipate Claim 1. Further investigation of its claims and detailed description would be crucial. It also potentially anticipates dependent claims regarding the nature of the media stream (video) and the goal of faster channel switching.

7. US20070044128A1: Video compression system

   • Full Citation: US20070044128A1, Daniel Witt, "Video compression system," published February 22, 2007.
   • Publication/Filing Date: Priority date: October 5, 2004; Publication date: February 22, 2007. (Note: Publication date is after US8542705's priority date, but its priority date is before).
   • Brief Description: This application describes a video compression system. While related to video encoding, it focuses on the compression algorithm itself rather than the streaming server's behavior upon a client connection.
   • Potential Anticipation (35 U.S.C. § 102): This patent primarily addresses video compression techniques. While it would inherently involve key frames and predictive frames, it is unlikely to disclose the specific streaming server logic of identifying key frames in buffers and selectively transmitting the earliest available one upon a new client connection or channel change, specifically omitting predictive frames. Therefore, it is unlikely to anticipate Claim 1 directly.

8. US20060136581A1: Strategies for configuring a server-based information-transmission infrastructure

   • Full Citation: US20060136581A1, Microsoft Corporation, "Strategies for configuring a server-based information-transmission infrastructure," published June 22, 2006.
   • Publication/Filing Date: Priority date: November 20, 2004; Publication date: June 22, 2006.
   • Brief Description: This application describes general strategies for configuring server infrastructure for information transmission. This is a broad topic related to network architecture and server management.
   • Potential Anticipation (35 U.S.C. § 102): This reference is too general to directly anticipate Claim 1 of US8542705. While it deals with server infrastructure, it does not appear to delve into the specific media stream handling logic concerning key frames and client connection requests as defined in Claim 1.

9. US20060143669A1: Fast channel switching for digital TV

   • Full Citation: US20060143669A1, Bitband Technologies Ltd., "Fast channel switching for digital TV," published June 29, 2006.
   • Publication/Filing Date: Priority date: December 23, 2004; Publication date: June 29, 2006.
   • Brief Description: This application specifically addresses "fast channel switching for digital TV," again indicating a direct relevance to the problem of reducing delay during channel changes.
   • Potential Anticipation (35 U.S.C. § 102): This patent is another highly relevant piece of prior art, explicitly tackling fast channel switching. It is highly likely to describe mechanisms that leverage key frames or similar synchronization points to enable quick display of a new channel. If it teaches identifying key frames in buffered media streams and providing the earliest one to a client upon a channel change request, specifically bypassing preceding predictive frames, it would substantially anticipate Claim 1 and its dependent claims related to video streams and channel changes. Further review of its claims and specification would be necessary.

10. US20070107026A1: Fast channel change with conditional return to multicasting

    • Full Citation: US20070107026A1, Sherer W P, "Fast channel change with conditional return to multicasting," published May 10, 2007.
    • Publication/Filing Date: Priority date: February 23, 2005; Publication date: May 10, 2007. (Note: Publication date is after US8542705's priority date, but its priority date is before).
    • Brief Description: This application combines "fast channel change" with "conditional return to multicasting," suggesting a system that quickly delivers a unicast stream for a channel change and then potentially switches back to a multicast stream for efficiency once synchronization is achieved.
    • Potential Anticipation (35 U.S.C. § 102): This is another highly relevant reference focusing on fast channel change, and it further elaborates on network efficiency (multicasting). A fast channel change often involves sending an I-frame or a new GOP. If this patent teaches identifying the earliest available key frame in a server-side buffer and immediately sending it to a client upon a channel change request, without transmitting intervening predictive frames, it would anticipate Claim 1. The "conditional return to multicasting" aspect is an additional layer of optimization, but the underlying fast channel change mechanism could still anticipate Claim 1.

11. US20070116437A1: Region-based processing of predicted pixels

    • Full Citation: US20070116437A1, Apple Computer, Inc., "Region-based processing of predicted pixels," published May 24, 2007.
    • Publication/Filing Date: Priority date: November 18, 2005; Publication date: May 24, 2007. (Note: Publication date is after US8542705's priority date, but its priority date is before).
    • Brief Description: This application describes techniques for processing predicted pixels within regions of video frames, likely to improve encoding/decoding efficiency or quality.
    • Potential Anticipation (35 U.S.C. § 102): This patent is focused on low-level video processing and prediction within frames, rather than the streaming server's behavior for new client connections or channel changes. It's unlikely to disclose the specific method of selecting and transmitting an initial key frame from a buffer, skipping predictive frames, as described in Claim 1 of US8542705.

12. US20110131622A1: Method and apparatus for immediate display of multicast IPTV over a bandwidth constrained network

    • Full Citation: US20110131622A1, Cisco Technology, Inc., "Method and apparatus for immediate display of multicast IPTV over a bandwidth constrained network," published June 2, 2011.
    • Publication/Filing Date: Priority date: February 27, 2006; Publication date: June 2, 2011. (Note: Publication date is after US8542705's priority date, but its priority date is before).
    • Brief Description: This application addresses the "immediate display" of multicast IPTV, especially in bandwidth-constrained environments, which strongly implies a focus on reducing initial display latency.
    • Potential Anticipation (35 U.S.C. § 102): This is another highly relevant reference, explicitly addressing "immediate display." For IPTV, especially multicast, quickly displaying content often involves mechanisms similar to those in US8542705, such as immediately starting with an I-frame or a suitable synchronization point. If this patent teaches identifying key frames in buffered streams and providing the earliest one to a client upon a connection request (e.g., tuning into a multicast channel), while ensuring no non-key frames are initially transmitted, it would anticipate Claim 1.

13. US20070242666A1: Apparatus for managing requests for data in a communication network

    • Full Citation: US20070242666A1, Alcatel, "Apparatus for managing requests for data in a communication network," published October 18, 2007.
    • Publication/Filing Date: Priority date: April 13, 2006; Publication date: October 18, 2007. (Note: Publication date is after US8542705's priority date, but its priority date is before).
    • Brief Description: This application describes an apparatus for managing data requests in a communication network, a broad topic concerning network resource management.
    • Potential Anticipation (35 U.S.C. § 102): This reference is too general to directly anticipate the specific method of handling media stream frames, key frame identification, and selective transmission upon client connection requests as defined in Claim 1 of US8542705.

14. US20070277219A1: Methods and systems to reduce channel selection transition delay in a digital network

    • Full Citation: US20070277219A1, John Toebes, "Methods and systems to reduce channel selection transition delay in a digital network," published November 29, 2007.
    • Publication/Filing Date: Priority date: May 26, 2006; Publication date: November 29, 2007. (Note: Publication date is after US8542705's priority date, but its priority date is before).
    • Brief Description: This application explicitly focuses on "reducing channel selection transition delay in a digital network," which is precisely the problem that US8542705 seeks to solve.
    • Potential Anticipation (35 U.S.C. § 102): This is another highly relevant piece of prior art. It is highly likely to disclose mechanisms for quickly displaying new content after a channel change. Such mechanisms would very often involve the rapid delivery of key frames or synchronization points. If it details identifying key frames in buffered media streams and providing the earliest one to a client upon a channel change, specifically omitting preceding predictive frames, it would strongly anticipate Claim 1 and its related dependent claims (e.g., Claim 7).

Summary of Most Relevant Prior Art:

Based on the titles and problem statements, the most relevant prior art references that potentially anticipate key aspects of US8542705's claims (especially Claim 1) are those explicitly mentioning "fast channel change," "minimizing channel change time," or "immediate display" in the context of streaming media/video:

• EP1523190A1 (Microsoft Corporation): Fast channel change
• US20050081244A1 (Barrett Peter T.): Fast channel change
• WO2006041784A2 (Wave7 Optics, Inc.): Minimizing channel change time for IP video
• US20060143669A1 (Bitband Technologies Ltd.): Fast channel switching for digital TV
• US20070107026A1 (Sherer W P): Fast channel change with conditional return to multicasting
• US20110131622A1 (Cisco Technology, Inc.): Method and apparatus for immediate display of multicast IPTV over a bandwidth constrained network
• US20070277219A1 (John Toebes): Methods and systems to reduce channel selection transition delay in a digital network

These references directly address the problem of reducing latency during channel changes or initial stream display, which is the primary objective of US8542705. While the precise details of their implementation (e.g., buffering on a per-GOP basis, specific key frame identification methods, explicit statement of not transmitting predictive frames initially) would require a full review of their specifications and claims, they represent the closest prior art in terms of the problem being solved and the general technical area. All of these would likely anticipate the broad concept of immediately providing a displayable frame upon a channel change to reduce delay. The novelty of US8542705 would then lie in the specific combination of features or the explicit details of how the key frame is identified and delivered, and the explicit exclusion of predictive frames.