Document:

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Exhibit 10.28

                   [LETTERHEAD OF PRINCETON VIDEO IMAGE, INC.]

February 27, 2001

Mr. James Crofton
Vice President & Chief Financial Officer
Sarnoff Corporation
201 Washington Road
CN5300
Princeton, NJ 08543-5300

         Re:      Amendment of Research Agreement, dated as of November 1, 1990
                  as amended as of December 31, 1993 and June 26, 1995, between
                  David Sarnoff Research Center ("Sarnoff") and Princeton
                  Electronic Billboard, now known as Princeton Video Image, Inc.
                  ("PEB" or "PVI")

Dear Jim:

This letter is to confirm our agreement to amend the above-referenced Research
Agreement to extend by three months the period during which minimum quarterly
royalty payments may be made either in cash or stock at the company's option.
Accordingly, the last paragraph of Article VII, paragraph 4(b) of the Agreement,
is hereby amended to read, in its entirety, as follows:

                  The minimum quarterly royalty payment to maintain the
                  licenses in the Sarnoff Property in effect beginning
                  one quarter after January 1, 1999 shall be One
                  Hundred Thousand Dollars ($100,000) for the Exclusive
                  Field defined in Article I, paragraph 1. For the
                  first two (2) years and three (3) months, PEB shall
                  have the option of paying the minimum royalty in cash
                  or in PEB stock at its last issue price. There shall
                  be no minimum royalties outside the Exclusive Field.

If you would kindly indicate your agreement to the amendment by signing the
acknowledgment below, we would be most appreciative.

Very truly yours.

/s/ Lawrence L. Epstein
-----------------------
Lawrence L. Epstein
Vice President and Chief Financial Officer

Agreed and Accepted

Sarnoff Corporation

By: /s/ James Crofton
   ---------------------
Its: Sr. VP & CFO
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EXHIBIT 10.31

NOTE: CERTAIN PORTIONS OF THIS DOCUMENT HAVE BEEN MARKED TO INDICATE THAT
CONFIDENTIALITY HAS BEEN REQUESTED FOR THIS CONFIDENTIAL INFORMATION. THE
CONFIDENTIAL PORTIONS HAVE BEEN OMITTED AND FILED SEPARATELY WITH THE SECURITIES
AND EXCHANGE COMMISSION.

                    Joint Collaboration and License Agreement

         This Agreement (this "Agreement") is made this 20th day of September
2001 by and between Princeton Video Image, Inc. ("PVI") and Cablevision Systems
Corporation ("Cablevision") (PVI and Cablevision, collectively, "we" or "us").

         We agree to collaborate to develop technology, including the computer
hardware, software and documentation, television set-top box interfaces,
equipment and related technology, to create virtual, in-content, interactive and
targeted advertising and enhancement products for downstream real-time insertion
of images into video at multiple distribution locations including, without
limitation, via a cable head-end, a satellite uplink facility, a neighborhood
distribution site, at individual homes, or individual receivers within a home
(such collaboration hereinafter referred to as the "Project(s)"). The Project's
primary goal will be to create such virtual, in-content, interactive and
targeted advertising and enhancement products specifically for use with
television distribution (the "Primary Goal").

         We further agree to collaborate to develop additional products and
applications relating to or flowing from the Project including, without
limitation, (i) instant replay and virtual camera angle applications similar to
the application and function of EyeVision, (ii) enhancements to provide viewer
control of actual or virtual camera angles, (iii) improvements to delivery of
multiple camera angles to set top boxes, and (iv) other products and
applications as may be mutually agreed upon (such additional collaboration
hereinafter referred to as the "Additional Project(s)"). With regard to PVI's
existing relationship with Revolution Co., LLC, PVI shall use its reasonable
efforts to obtain all necessary rights and permissions from Revolution Co., LLC
[CONFIDENTIAL TREATMENT REQUESTED] in support of and for use in connection with
the Additional Projects.

         We agree that the following terms shall govern our collaboration:
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Definitions                Capitalized terms herein not otherwise defined shall
                           have the meanings described under the L-VIS System
                           License Agreement dated February 4, 2001 between the
                           parties (the "L-VIS Agreement").

                           "Content Provider" shall mean an entity owning or
                           controlling video programming content.

                           "Network" shall mean a broadcast channel for the
                           dissemination of video programming content through a
                           television system, cable system, satellite system or
                           other such similar broadcasting system.

                           "Net Revenues" means Revenues received, net of any
                           payments Cablevision or its Licensed Affiliate makes
                           to non-Affiliate Networks or Content Providers to
                           obtain rights to insert Electronic Images in order to
                           obtain Revenue, provided that only Revenues obtained
                           for actual insertion of Electronic Images shall be
                           included, and that any other ancillary revenues,
                           including, without limitation, revenues related to
                           "e-Commerce" or "T-Commerce" transactions, shall be
                           excluded.

                           "System Operator" shall mean an entity providing a
                           system for distributing Networks to end users, such
                           as the Cablevision cable distribution system.

Collaboration              We will agree upon the specifics of our
                           collaboration, such as the stated goals, activities,
                           time lines, testing and benchmarks where we will each
                           commit to devote resources and personnel reasonably
                           available to us in a manner to be determined to
                           accomplish the goals of the collaboration. We will
                           negotiate and agree upon our respective commitment of
                           assets and resources to the collaboration.

Cross-Licenses             Each of us hereby grants to the other non-exclusive
                           licenses of intellectual property we own or control
                           to the extent necessary and appropriate to the
                           advancement and commercialization of the Project and
                           Additional Projects.

License to PVI             Cablevision hereby grants to PVI the exclusive
                           perpetual
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                           worldwide [CONFIDENTIAL TREATMENT REQUESTED] right to
                           use, sublicense or otherwise commercialize, for all
                           purposes, any technology and intellectual property
                           rights jointly developed under or as part of the
                           Project and Additional Projects, which Cablevision
                           jointly owns and controls with PVI, subject to
                           retained rights.

                           Cablevision hereby further grants to PVI a
                           non-exclusive perpetual worldwide [CONFIDENTIAL
                           TREATMENT REQUESTED] right to use, sublicense or
                           otherwise commercialize any technology and
                           intellectual property which Cablevision solely owns
                           or controls, to the extent necessary to allow PVI to
                           exploit the Projects and Additional Projects
                           developed in collaboration with Cablevision.

License to                 PVI hereby grants to Cablevision and each of its
Cablevision                Licensed Affiliates the non-exclusive perpetual
                           worldwide right to make, have made, use, and have
                           supplied products and services that use, any
                           technology, intellectual property and products
                           developed in collaboration with Cablevision under or
                           as part of the Project and Additional Projects, which
                           PVI owns or controls solely or jointly with
                           Cablevision, or which PVI is otherwise entitled to
                           license or sublicense, upon terms described below.

                           Unless otherwise specifically agreed, licenses to
                           technology and intellectual property developed under
                           or as part of, and products emanating from, the
                           Project or Additional Projects, and not directly
                           relating to the Primary Goal, [CONFIDENTIAL TREATMENT
                           REQUESTED].

                           Unless agreed to by PVI in advance, in writing, or
                           otherwise permitted in accordance with the other
                           terms of this Agreement, Cablevision and its Licensed
                           Affiliates shall not: (i) sublicense, lease, sell,
                           assign, rent or otherwise transfer to others,
                           otherwise dispose of, rights granted hereunder to use
                           technology licensed by PVI; or (ii) transfer, assign,
                           relicense or otherwise dispose of such license rights
                           under this Agreement.

                           Technology and intellectual property developed under
                           or as part of, and products emanating from, the
                           Project or Additional Projects, relating to the
                           Primary Goal, are hereby licensed upon the following
                           terms:
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                           With respect to Cablevision's and its Licensed
                           Affiliates' rights as a System Operator where
                           Cablevision or its Licensed Affiliate performs
                           downstream insertion of Electronic Images into
                           programming content owned or controlled by any
                           rightsholders (whether or not Affiliates of
                           Cablevision) the following terms shall apply:

                           (1)      Cablevision and its Licensed Affiliates
                                    shall pay PVI the royalty or revenue sharing
                                    rate set forth below multiplied by the
                                    amount of Net Revenues.

                           (2)      Cablevision and its Licensed Affiliates will
                                    have an initial 6-month grace period to use
                                    licensed technology for promotion of
                                    Cablevision and/or its Licensed Affiliates,
                                    before royalty obligations commence. The
                                    initial 6-month grace period shall commence,
                                    with respect to each product, from the time
                                    such product is first used by Cablevision or
                                    a Licensed Affiliate.

                           (3)      Subsequently, Cablevision shall have a
                                    perpetual [CONFIDENTIAL TREATMENT REQUESTED]
                                    right to use up to 25% of Electronic Image
                                    avails (rounded up to the nearest whole
                                    avail) for the benefit of Cablevision and/or
                                    its Licensed Affiliates.

                           (4)      PVI may not charge (and agrees to waive, if
                                    it charges generally) [CONFIDENTIAL
                                    TREATMENT REQUESTED], to any Network or
                                    Content Provider for the delivery of enabled
                                    programming content to Cablevision or its
                                    Licensed Affiliates for downstream insertion
                                    of Electronic Images.

                           (5)      At the request of Cablevision or any of its
                                    Licensed Affiliates, PVI shall convey a
                                    [CONFIDENTIAL TREATMENT REQUESTED] perpetual
                                    non-exclusive license to any Network or
                                    Content Provider solely for the delivery of
                                    enabled programming content to Cablevision
                                    or its Licensed Affiliates for downstream
                                    insertion of Electronic Images.

                           (6)      [CONFIDENTIAL TREATMENT REQUESTED].
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                           With respect to Cablevision's and its Licensed
                           Affiliates' rights as a Content Provider or Network,
                           where Cablevision or its Licensed Affiliate enables
                           programming content for downstream insertion of
                           Electronic Images by a System Operator (whether or
                           not an Affiliate of Cablevision):

                           (1)      PVI will provide all necessary equipment
                                    requested by Cablevision or any of the
                                    Licensed Affiliates at [CONFIDENTIAL
                                    TREATMENT REQUESTED].

                           (2)      PVI will provide any requested services to
                                    enable programming content [CONFIDENTIAL
                                    TREATMENT REQUESTED].

                           (3)      PVI shall not charge any System Operator a
                                    higher royalty or other fee for Electronic
                                    Image insertion based on the fact that
                                    Cablevision or its Licensed Affiliate is the
                                    Content Provider or Network being
                                    distributed over such System Operator's
                                    system than it charges for such insertion
                                    with respect to any other Content Provider
                                    or Network distributed over such system.
                                    [CONFIDENTIAL TREATMENT REQUESTED].

Royalty rate               The royalty or revenue sharing rate shall be

                           [CONFIDENTIAL TREATMENT REQUESTED]

                           Revenue from insertion of Electronic Images by
                           Cablevision or its Licensed Affiliates under the
                           L-VIS Agreement and under the joint collaboration and
                           licensing agreement contemplated hereby shall count
                           towards the amount of cumulative Revenues above, as
                           well as under the L-VIS Agreement.

                           Any license fees prepaid under Section 3.1 of the
                           L-VIS System License Agreement shall be creditable
                           against equipment costs, services costs, royalties,
                           and other monetary obligations incurred as set forth
                           herein.
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Limitation of              For the purposes hereof, the definition of Licensed
Licensed                   Affiliate shall not include any entity, in its role
System Operator            as System Operator, that Cablevision acquires, if,
Affiliates                 after giving effect to such acquisition and together
                           with all prior acquisitions of such entities after
                           the date of the definitive agreement, such
                           acquisition adds a net total of more than 10 million
                           acquired subscribers (after discounting for any
                           subscribers sold).

Inventions                 Each party (including the Licensed Affiliates) will
                           own intellectual property developed by its own
                           employees. Intellectual property developed jointly
                           will be owned jointly. Cablevision and PVI will
                           coordinate patent prosecution and maintenance of
                           joint inventions with the related technology owned
                           independently. All inventions and joint inventions
                           are cross-licensed as provided above.

We agree that the collaboration, licenses and all other terms and conditions
governing our relationship and the Project will be embodied in one or more
additional mutually acceptable definitive agreements or other documents with
other reasonable and customary terms and conditions similar to those contained
in the L-VIS Agreement, to the extent we agree that terms and conditions of the
L-VIS Agreement would be applicable. We agree to negotiate in good faith and
with reasonable diligence to implement such agreements and documents as may be
reasonably appropriate from time to time. Nevertheless, this Agreement
constitutes our binding agreement with respect to its subject matter and may be
enforced by either of us unless and until we sign another agreement that, by its
express terms, supercedes or supplements this Agreement. The licenses and
commitments described in this Agreement shall be enforceable whether or not any
additional agreements are executed by us.

ACCEPTED AND AGREED TO AS OF THE 20th DAY OF SEPTEMBER, 2001.

PRINCETON VIDEO IMAGE, INC.            CABLEVISION SYSTEMS CORPORATION

By:    /s/ Dennis P. Wilkinson         By:    /s/ Andrew B. Rosengard
Name:  Dennis P. Wilkinson             Name:  Andrew B. Rosengard
Title: President & CEO                 Title: Executive Vice President - Finance

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