Document:

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                                                                  EXHIBIT 4.12.2

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                   CHANCELLOR MEDIA CORPORATION OF LOS ANGELES

                                   as Obligor

                                       AND

                           the Guarantors named herein

                                       AND

                              THE BANK OF NEW YORK,

                                   as Trustee

                            -------------------------

                          FIRST SUPPLEMENTAL INDENTURE

                           Dated as of August 23, 1999

                                       to

                                    Indenture

                          Dated as of November 17, 1998

                           --------------------------

                                  $750,000,000

                                 8% Senior Notes

                                    due 2008

================================================================================

<PAGE>   2

         FIRST SUPPLEMENTAL INDENTURE dated as of August 23, 1999, among
CHANCELLOR MEDIA CORPORATION OF LOS ANGELES, a Delaware corporation (the
"Company"), the current subsidiary guarantors listed on Schedule I hereto
(collectively, the "Current Subsidiary Guarantors"), the new subsidiary
guarantors listed on Schedule II hereto (collectively, the "New Subsidiary
Guarantors") and THE BANK OF NEW YORK, a New York banking corporation, as
Trustee (the "Trustee").

         WHEREAS, the Company and the Current Subsidiary Guarantors have
heretofore executed and delivered to the Trustee an Indenture dated as of
November 17, 1998 (the "Indenture"), providing for the issuance of $750,000,000
aggregate principal amount 8% Senior Notes due 2008 (the "Notes"); and

         WHEREAS, the Company, the Current Subsidiary Guarantors, the New
Subsidiary Guarantors and the Trustee desire by this First Supplemental
Indenture (i) to cure an ambiguity, defect or inconsistency in the Indenture
without the consent of the Holders of the Securities pursuant to section 9.01
thereof and (ii) to add the New Subsidiary Guarantors as guarantors pursuant to
the terms of the Indenture, including Sections 4.19, 9.01 and 11.03 thereof; and

         WHEREAS, the execution and delivery of this First Supplemental
Indenture has been authorized by resolutions of the Boards of Directors of the
Company, each of the Current Subsidiary Guarantors, and each of the New
Subsidiary Guarantors; and

         WHEREAS, all conditions and requirements necessary to make this First
Supplemental Indenture a valid, binding legal instrument in accordance with its
terms have been performed and fulfilled by the parties hereto and the execution
and delivery thereof have been in all respects duly authorized by the parties
hereto.

         NOW, THEREFORE, in consideration of the above premises, each party
agrees, for the benefit of the others and for the equal and ratable benefit of
the holders of the Notes, as follows:

                                   ARTICLE I.

                     ASSUMPTION OF OBLIGATIONS AS GUARANTOR

     Section 1.01. Assumption. Each of the New Subsidiary Guarantors hereby
expressly and unconditionally assumes each and every covenant, agreement and
undertaking of a Guarantor in the Indenture as of the date of this First
Supplemental Indenture, and also hereby expressly and unconditionally assumes
each and every covenant, agreement and undertaking of a Guarantor in each Note
outstanding on the date of this First Supplemental Indenture.

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                                   ARTICLE IA.

                                   AMENDMENTS

     Section 1A.01. Amendments. The first paragraph of Section 6(a) of the Form
of Global Security attached to the Indenture as Exhibit A-1 is hereby amended
and restated in its entirety as follows:

                  "The Securities will be redeemable, at the Company's option,
in whole at any time or in part from time to time, at a redemption price equal
to 100% of the principal amount thereof plus the Applicable Premium (as defined
below), if greater than zero, as of, and accrued and unpaid interest, if any, to
the date of redemption (the "Redemption Date") (subject to the right of holders
of record on the relevant record date to receive interest due on the relevant
interest payment date in respect of then outstanding Securities)."

                                   ARTICLE II.

                            MISCELLANEOUS PROVISIONS

     Section 2.01. Terms Defined. For all purposes of this First Supplemental
Indenture, except as otherwise defined or unless the context otherwise requires,
terms used in capitalized form in this First Supplemental Indenture and defined
in the Indenture have the meanings specified in the Indenture.

     Section 2.02. Indenture. Except as amended hereby, the Indenture and the
Notes are in all respects ratified and confirmed and all the terms shall remain
in full force and effect.

     Section 2.03. Governing Law. THIS FIRST SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK,
AS APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT
REGARD TO PRINCIPLES OF CONFLICT OF LAWS.

     Section 2.04. Successors. All agreements of the Company, the Current
Subsidiary Guarantors and the New Subsidiary Guarantors in this First
Supplemental Indenture and the Notes shall bind their successors. All agreements
of the Trustee in this First Supplemental Indenture shall bind its successors.

     Section 2.05. Duplicate Originals. All parties may sign any number of
copies of this First Supplemental Indenture. Each signed copy shall be an
original, but all of them together shall represent the same agreement.

     Section 2.06. Severability. In case any one or more of the provisions in
this First Supplemental Indenture or in the Notes shall be held invalid, illegal
or unenforceable, in any respect for any reason, the validity, legality and
enforceability of any such provision in every other respect and

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of the remaining provisions shall not in any way be affected or impaired
thereby, it being intended that all of the provisions hereof shall be
enforceable to the full extent permitted by law.

     Section 2.07. Trustee Disclaimer. The Trustee accepts the amendment of the
Indenture effected by this First Supplemental Indenture and agrees to execute
the trust created by the Indenture as hereby amended, but on the terms and
conditions set forth in the Indenture, including the terms and provisions
defining and limiting the liabilities and responsibilities of the Trustee, which
terms and provisions shall in like manner define and limit its liabilities and
responsibilities in the performance of the trust created by the Indenture as
hereby amended, and without limiting the generality of the foregoing, the
Trustee shall not be responsible in any manner whatsoever for or with respect to
any of the recitals or statements contained herein, all of which recitals or
statements are made solely by the Company, the Current Subsidiary Guarantors and
the New Subsidiary Guarantors, or for or with respect to (i) the validity or
sufficiency of this First Supplemental Indenture or any of the terms or
provisions hereof, (ii) the proper authorization hereof by the Company, the
Current Subsidiary Guarantors and the New Subsidiary Guarantors by corporate
action or otherwise, (iii) the due execution hereof by the Company, the Current
Subsidiary Guarantors and the New Subsidiary Guarantors or (iv) the consequences
(direct or indirect and whether deliberate or inadvertent) of any amendment
herein provided for, and the Trustee makes no representation with respect to any
such matters.

     Section 2.08. Effectiveness. This First Supplemental Indenture shall become
effective, once executed, upon receipt by the Trustee of a certificate of an
appropriate officer of the Company; and an opinion of Weil, Gotshal & Manges
LLP, counsel to the Company, each of which shall be dated no earlier than the
date hereof.

            (THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK)

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         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the day and year written above.

                                     CHANCELLOR MEDIA CORPORATION OF
                                     LOS ANGELES, as Obligor

                                     /s/ William S. Banowsky, Jr.
                                     -------------------------------------------
                                     By:      William S. Banowsky, Jr.
                                     Title:   Executive Vice President

Attest:  /s/
         ----------------------------

                                     On Behalf of Each of the Current Subsidiary
                                     Guarantors Listed on Schedule I hereto

                                     /s/ William S. Banowsky, Jr.
                                     -------------------------------------------
                                     By:      William S. Banowsky, Jr.
                                     Title:   Executive Vice President

Attest:  /s/
         ----------------------------

                                     On Behalf of Each of the New Subsidiary
                                     Guarantors Listed on Schedule II hereto

                                     /s/ William S. Banowsky, Jr.
                                     -------------------------------------------
                                     By:      William S. Banowsky, Jr.
                                     Title:   Executive Vice President

Attest:  /s/
         ----------------------------

                                     THE BANK OF NEW YORK,
                                     as Trustee

                                     /s/ Remo J. Reale
                                     -------------------------------------------
                                     By:      Remo J. Reale
                                     Title:   Vice President

Attest:  /s/
         ----------------------------

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                                   SCHEDULE I

                          CURRENT SUBSIDIARY GUARANTORS
                     (ALL SUBSIDIARY GUARANTORS ARE DELAWARE
                  CORPORATIONS EXCEPT AS EXPRESSLY INDICATED)

Amcast Radio Sales, Inc.
The AMFM Radio Networks, Inc.
Broadcast Architecture, Inc. (a Massachusetts corporation)
Chancellor Media Air Services Corporation
Chancellor Media Corporation of California
Chancellor Media Corporation of Charlotte
Chancellor Media Corporation of Houston
Chancellor Media Corporation of Illinois
Chancellor Media Corporation of Massachusetts
Chancellor Media Corporation of Miami
Chancellor Media Corporation of Michigan
Chancellor Media Corporation of New York
Chancellor Media Corporation of St. Louis
Chancellor Media Corporation of the Keystone State
Chancellor Media Corporation of The Lone Star State
Chancellor Media Corporation of Washington, D.C.
Chancellor Media Licensee Company
Chancellor Media Martin Corporation
Chancellor Media MW Sign Corporation
Chancellor Media Nevada Sign Corporation
Chancellor Media of Houston Limited Partnership (a Delaware limited partnership)
Chancellor Media Outdoor Corporation
Chancellor Media Pennsylvania License Corp.
Chancellor Media Radio Licenses, LLC (a Delaware limited liability company)
Chancellor Media/Riverside Broadcasting Co., Inc.
Chancellor Media/Shamrock Broadcasting, Inc.
Chancellor Media/Shamrock Broadcasting of Texas, Inc. (a Texas corporation)
Chancellor Media/Shamrock Radio Licenses, LLC (a Delaware limited
 liability company)
Chancellor Media/WAXQ, Inc.
Chancellor Media Whiteco Outdoor Corporation
Christal Radio Sales, Inc.
Dowling Company Incorporated (a Virginia corporation)
Eastman Radio Sales, Inc.
Hardin Development Corporation (a Florida corporation)
Katz Cable Corporation
Katz Communications, Inc.
Katz Media Corporation
Katz Millennium Marketing, Inc.
KIOI License Corp.
KLOL License Limited Partnership (a Delaware limited partnership)

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KZPS/KDGE License Corp.
Martin Media (a California limited partnership)
The National Payroll Company, Inc.
Parsons Development Company  (a Florida corporation)
Radio 100, L.L.C. (a Delaware limited liability company)
Revolution Outdoor Advertising, Inc. (a Florida corporation)
Seltel Inc.
WAXQ License Corp.
Western Poster Service, Inc. (a Texas corporation)
WIOQ License Corp.
WLTW License Corp.
WTOP License Limited Partnership (a Delaware limited partnership)

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                                   SCHEDULE II

                            NEW SUBSIDIARY GUARANTORS
       (ALL SUBSIDIARY GUARANTORS ARE DELAWARE LIMITED LIABILITY COMPANIES
                         EXCEPT AS EXPRESSLY INDICATED)

Chancellor Media Corporation of Ohio (a Delaware corporation)
Cleveland Radio Licenses, LLC
Outdoor Promotions West, LLC
Transit America Las Vegas, LLC
Triumph Outdoor Holdings, LLC
Triumph Outdoor Louisiana, LLC
Triumph Outdoor Rhode Island, LLC
Zebra Broadcasting Corporation (an Ohio corporation)

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                                                                  EXHIBIT 4.12.3

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                               AMFM OPERATING INC.

                                   AS OBLIGOR

                                       AND

                           THE GUARANTORS NAMED HEREIN

                                       AND

                              THE BANK OF NEW YORK,

                                   AS TRUSTEE

                  --------------------------------------------

                          SECOND SUPPLEMENTAL INDENTURE

                          DATED AS OF NOVEMBER 19, 1999

                                       TO

                                    INDENTURE

                          DATED AS OF NOVEMBER 17, 1998

                  --------------------------------------------

                                  $750,000,000

                            8% SENIOR NOTES DUE 2008

================================================================================

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         SECOND SUPPLEMENTAL INDENTURE dated as of November 19, 1999, among AMFM
OPERATING INC., a Delaware corporation (formerly Capstar Communications, Inc.,
the "Company"), the subsidiaries listed on Schedule I hereto (collectively, the
"New Subsidiary Guarantors") and THE BANK OF NEW YORK, a New York banking
corporation, as Trustee (the "Trustee").

         WHEREAS, Chancellor Media Corporation of Los Angeles, a Delaware
corporation "CMCLA") and certain subsidiary guarantors have heretofore executed
and delivered to the Trustee an Indenture dated as of November 17, 1998, as
amended by that certain First Supplemental Indenture dated as of August 23, 1999
by and among CMCLA, the guarantors named therein and the Trustee (as amended,
the "Indenture"), providing for the issuance of $750,000,000 aggregate principal
amount of 8% Senior Notes due 2008 (the "Notes");

         WHEREAS, pursuant to that certain Agreement and Plan of Merger by and
among CMCLA, Capstar Radio Broadcasting Partners, Inc., a Delaware corporation
("Capstar Radio"), SBI Holding Corporation, a Delaware corporation ("SBI"), and
the Company, dated as of November 19, 1999 (the "Merger Agreement"), among other
things, CMCLA, Capstar Radio, and SBI merged with and into the Company (the
"Merger");

         WHEREAS, the Company, the New Subsidiary Guarantors and the Trustee
desire by this Second Supplemental Indenture (i) pursuant to and as contemplated
by Section 5.01(a)(1)(B) of the Indenture, that the Company expressly assume all
of the obligations under the Notes and the Indenture, and (ii) pursuant to and
as contemplated by the provisions of the Indenture relating to the addition of
guarantors, including Sections 4.19, 9.01 and 11.03, to add the New Subsidiary
Guarantors as guarantors pursuant to the terms of the Indenture;

         WHEREAS, the execution and delivery of this Second Supplemental
Indenture has been authorized by resolutions of the Boards of Directors of the
Company and each of the New Subsidiary Guarantors; and

         WHEREAS, all conditions and requirements necessary to make this Second
Supplemental Indenture a valid, binding legal instrument in accordance with its
terms have been performed and fulfilled by the parties hereto and the execution
and delivery thereof have been in all respects duly authorized by the parties
hereto.

         NOW, THEREFORE, in consideration of the above premises, each party
agrees, for the benefit of the others and for the equal and ratable benefit of
the holders of the Notes, as follows:

                                    ARTICLE I

                       ASSUMPTION OF OBLIGATIONS AS ISSUER

         Section 1.01 ASSUMPTION. The Company hereby expressly and
unconditionally assumes each and every covenant, agreement and undertaking of
CMCLA under the Indenture as of the date of this Second Supplemental Indenture,
and also hereby expressly and unconditionally assumes each

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and every covenant, agreement and undertaking of CMCLA under each Note
outstanding on the date of this Second Supplemental Indenture.

                                   ARTICLE II

                     ASSUMPTION OF OBLIGATIONS AS GUARANTOR

         Section 2.01 ASSUMPTION. Each of the New Subsidiary Guarantors hereby
expressly and unconditionally assumes each and every covenant, agreement and
undertaking of a Guarantor in the Indenture as of the date of this Second
Supplemental Indenture, and also hereby expressly and unconditionally assumes
each and every covenant, agreement and undertaking of a Guarantor in each Note
outstanding on the date of this Second Supplemental Indenture.

                                   ARTICLE III

                            MISCELLANEOUS PROVISIONS

         Section 3.01 DEFINED TERMS. For all purposes of this Second
Supplemental Indenture, except as otherwise defined or unless the context
otherwise requires, terms used in capitalized form in this Second Supplemental
Indenture and defined in the Indenture have the meanings specified in the
Indenture.

         Section 3.02 INDENTURE. Except as amended hereby, the Indenture and the
Notes are in all respects ratified and confirmed and all the terms shall remain
in full force and effect.

         Section 3.03 GOVERNING LAW. THIS SECOND SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK,
AS APPLIED TO CONTRACTS MADE AND PERFORMED WITHIN THE STATE OF NEW YORK, WITHOUT
REGARD TO PRINCIPLES OF CONFLICT OF LAWS.

         Section 3.04 SUCCESSORS. All agreements of the Company and the New
Subsidiary Guarantors in this Second Supplemental Indenture and the Notes shall
bind their successors. All agreements of the Trustee in this Second Supplemental
Indenture shall bind its successors.

         Section 3.05 DUPLICATE ORIGINALS. All parties may sign any number of
copies of this Second Supplemental Indenture. Each signed copy shall be an
original, but all of them together shall represent the same agreement.

         Section 3.06 SEVERABILITY. In case any one or more of the provisions in
this Second Supplemental Indenture or in the Notes shall be held invalid,
illegal or unenforceable, in any respect for any reason, the validity, legality
and enforceability of any such provision in every other respect and of the
remaining provisions shall not in any way be affected or impaired thereby, it
being intended that all of the provisions hereof shall be enforceable to the
full extent permitted by law.

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         Section 3.07 TRUSTEE DISCLAIMER. The Trustee accepts the amendment of
the Indenture effected by this Second Supplemental Indenture and agrees to
execute the trust created by the Indenture as hereby amended, but on the terms
and conditions set forth in the Indenture, including the terms and provisions
defining and limiting the liabilities and responsibilities of the Trustee, which
terms and provisions shall in like manner define and limit its liabilities and
responsibilities in the performance of the trust created by the Indenture as
hereby amended, and without limiting the generality of the foregoing, the
Trustee shall not be responsible in any manner whatsoever for or with respect to
any of the recitals or statements contained herein, all of which recitals or
statements are made solely by the Company and the New Subsidiary Guarantors, or
for or with respect to (i) the validity or sufficiency of this Second
Supplemental Indenture or any of the terms or provisions hereof, (ii) the proper
authorization hereof by the Company and the New Subsidiary Guarantors by
corporate action or otherwise, (iii) the due execution hereof by the Company and
the New Subsidiary Guarantors or (iv) the consequences (direct or indirect and
whether deliberate or inadvertent) of any amendment herein provided for, and the
Trustee makes no representation with respect to any such matters.

         Section 3.08 EFFECTIVENESS. This Second Supplemental Indenture shall
become effective, once executed, upon receipt by the Trustee of a certificate of
the appropriate officers of the Company; and an opinion of Vinson & Elkins
L.L.P., counsel to the Company, each of which shall be dated no earlier than the
date hereof.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK]

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         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the day and year written above.

                                  AMFM OPERATING INC.,
                                  as Obligor

                                  By:  /s/ W. Schuyler Hansen
                                     ------------------------------------------
                                     W. Schuyler Hansen
                                     Senior Vice President and Chief Accounting
                                        Officer

                                  ON BEHALF OF EACH OF THE NEW SUBSIDIARY
                                  GUARANTORS LISTED ON SCHEDULE I HERETO*

                                  By:  /s/ Kathy Archer
                                     ------------------------------------------
                                     Kathy Archer
                                     Senior Vice President

                                  THE BANK OF NEW YORK,
                                  as Trustee

                                   /s/ Remo J. Reale
                                  ---------------------------------------------
                                  By:     Remo J. Reale
                                     ------------------------------------------
                                  Title:  Vice President
                                        ---------------------------------------

---------------------------

*For Capstar TX Limited Partnership, by Capstar Radio Operating Company, its
general partner.

<PAGE>   6

                                     CAPSTAR ROYALTY I CORPORATION
                                     CAPSTAR ROYALTY II CORPORATION
                                     CAPSTAR COMMUNICATIONS OF
                                       CALIFORNIA, INC.,
                                     as New Subsidiary Guarantors

                                  By:  /s/ Kathy Archer
                                     ------------------------------------------
                                     Kathy Archer
                                     President

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                                   SCHEDULE I

                            NEW SUBSIDIARY GUARANTORS
            (ALL NEW SUBSIDIARY GUARANTORS ARE DELAWARE CORPORATIONS
                         EXCEPT AS EXPRESSLY INDICATED)

Chancellor Marketing Group, Inc. (a Virginia corporation)
CBC Acquisition Company, Inc.
Capstar Acquisition Company, Inc.
Capstar Operating Corporation
Capstar Royalty II Corporation
Osborn Entertainment Enterprises Corporation
Music Hall Club, Inc. (a West Virginia corporation)
Jamboree in the Hills
Capstar Royalty I Corporation
Triathlon Broadcasting Company
Capstar Communications California, Inc.
Capstar Radio Operating Company
WPYX, Inc. (a New York corporation)
Capstar TX Limited Partnership (a Delaware limited partnership)

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