SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549




                                  SCHEDULE 13G
                    Under the Securities Exchange Act of 1934
                                (Amendment No. 1)



                                  RENTRAK CORP.
                       ----------------------------------
                                (Name of Issuer)

                Class A Common Stock, $0.001 Par Value Per Share
               --------------------------------------------------
                         (Title of Class of Securities)

                                   760174 102
                              --------------------
                                 (CUSIP Number)


         Check the  appropriate  box to  designate  the rule  pursuant to which
this Schedule is filed:
                         / / Rule 13d-1(b)
                         /X/ Rule 13d-1(c)
                         / /Rule 13d-1(d)

         Check the following box if a fee is being paid with this statement |_|.
(A fee is not required only if the filing person:  (1) has a previous  statement
on file reporting beneficial ownership of more than five percent of the class of
securities  described  in Item 1;  and (2) has  filed  no  amendment  subsequent
thereto reporting  beneficial  ownership of five percent or less of such class.)
(See Rule 13d-7.)

         *The  remainder  of this cover page shall be filled out for a reporting
person's  initial  filing on this  form with  respect  to the  subject  class of
securities,  and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

         The information  required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise  subject to the  liabilities of that section of
the Act but shall be subject to all other  provisions of the Act  (however,  see
the Notes).

                       (Continued on the following pages)




                                   Page 1 of 7





CUSIP NO.  760174 102

(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                    Blockbuster Inc.
         -----------------------------------------------------------------------
                    I.R.S. Identification No. 52-1655102
         -----------------------------------------------------------------------

(2)      Check the Appropriate Box if a Member of Group (See Instructions)

          /  /     (a) ---------------------------------------------------------

          /  /     (b) ---------------------------------------------------------


(3)      SEC Use Only ----------------------------------------------------------

(4)      Citizenship or Place of Organization                Delaware
                                                  ------------------------------

- --------------
Number of           (5)      Sole Voting Power                     0
                                                        ------------------------
  Shares
Beneficially        (6)      Shared Voting Power               1,000,000*
                                                        ------------------------
 Owned by
   Each             (7)      Sole Dispositive Power                0
                                                        ------------------------
Reporting
Person With         (8)      Shared Dispositive Power          1,000,000*
- --------------                                          ---------------------


(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                    1,000,000*
         -----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain Shares
         (See Instructions)
                           -----------------------------------------------------

(11)     Percent of Class Represented by Amount in Row (9)
                    9.37%
         -----------------------------------------------------------------------

(12)     Type of Reporting Person (See Instructions)                 CO
                                                            --------------------


             (*All shares underlie currently exercisable warrants)




                                   Page 2 of 7






CUSIP NO.  760174 102

(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                    VIACOM INC.
         -----------------------------------------------------------------------
                    I.R.S. Identification No. 04-2949533
         -----------------------------------------------------------------------

(2)      Check the Appropriate Box if a Member of Group (See Instructions)

         /  /     (a)-----------------------------------------------------------

         /  /     (b)-----------------------------------------------------------


(3)      SEC Use Only
                      ----------------------------------------------------------

(4)      Citizenship or Place of Organization                   Delaware
                                                       -------------------------


- --------------
Number of           (5)      Sole Voting Power                     0
                                                        ------------------------
  Shares
Beneficially        (6)      Shared Voting Power               1,000,000*
                                                        ------------------------
 Owned by
   Each             (7)      Sole Dispositive Power                0
                                                        ------------------------
Reporting
Person With         (8)      Shared Dispositive Power          1,000,000*
- --------------                                          ---------------------


(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                    1,000,000*
         -----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain Shares
         (See Instructions)
                           -----------------------------------------------------

(11)     Percent of Class Represented by Amount in Row (9)
                    9.37%
         -----------------------------------------------------------------------

(12)     Type of Reporting Person (See Instructions)                 CO
                                                            --------------------



             (*All shares underlie currently exercisable warrants)





                                  Page 3 of 7





CUSIP NO.  760174 102

(1)      Name of Reporting Person
         S.S. or I.R.S. Identification No. of Above Person
                    SUMNER M. REDSTONE
         -----------------------------------------------------------------------
                    S.S. No.
         -----------------------------------------------------------------------

(2)      Check the Appropriate Box if a Member of Group (See Instructions)

         /  /     (a)-----------------------------------------------------------

         /  /     (b)-----------------------------------------------------------


(3)      SEC Use Only
                      ----------------------------------------------------------

(4)      Citizenship or Place of Organization               United States
                                                       -------------------------


- --------------
Number of           (5)      Sole Voting Power                     0
                                                        ------------------------
  Shares
Beneficially        (6)      Shared Voting Power               1,000,000*
                                                        ------------------------
 Owned by
   Each             (7)      Sole Dispositive Power                0
                                                        ------------------------
Reporting
Person With         (8)      Shared Dispositive Power          1,000,000*
- --------------                                          ---------------------


(9)      Aggregate Amount Beneficially Owned by Each Reporting Person
                    1,000,000*
         -----------------------------------------------------------------------

(10)     Check if the Aggregate Amount in Row (9) Excludes Certain Shares
         (See Instructions)
                           -----------------------------------------------------

(11)     Percent of Class Represented by Amount in Row (9)
                    9.37%
         -----------------------------------------------------------------------

(12)     Type of Reporting Person (See Instructions)                 IN
                                                            --------------------


             (*All shares underlie currently exercisable warrants)





                                   Page 4 of 7






Item 1.   Identity of Issuer

     This  Amendment  No. 1 amends the  Statement on Schedule 13G filed with the
Securities  and Exchange  Commission on March 16, 1998 by the  undersigned  with
respect to the Common Stock, par value $0.001 per share (the "Common Stock"), of
Rentrak Corp.  (the  "Issuer").  The Issuer's  principal  executive  offices are
located at One Airport Center, 7700 NE Ambassador Place, Portland, Oregon 97220.



Item 2.   Identity of Reporting Persons and Background

          This Item 2 is amended as follows:

     This  Amendment  No. 1 is filed on behalf of  Blockbuster  Inc., a Delaware
corporation ("BI"), with a principal address of 1201 Elm Street,  Dallas,  Texas
75270,  Viacom  International  Inc.,  a  Delaware  corporation  ("VII"),  with a
principal  address of 1515 Broadway,  New York,  New York 10036,  Viacom Inc., a
Delaware  corporation  ("VI"),  with a principal  address of 1515 Broadway,  New
York, New York 10036, National Amusements, Inc., a Maryland corporation ("NAI"),
with a principal address of 200 Elm Street, Dedham, Massachusetts 02026, and Mr.
Sumner M. Redstone (collectively, the "Reporting Persons").

     BI,  successor-in-interest  to  Blockbuster  Videos,  Inc. and  Blockbuster
Entertainment  Inc.,  is a wholly owned  subsidiary  of VII,  which in turn is a
wholly owned subsidiary of VI.  Approximately  67% of VI's voting stock is owned
by NAI; Mr. Sumner M. Redstone, a U.S. citizen, is the controlling  shareholder,
Chairman,  Chief Executive  Officer and President of NAI, the Chairman and Chief
Executive Officer of VI and President and Chief Executive Officer of VII.



Item 3.   If this Statement  is filed  pursuant  to  ss.240.13d-1(c)
          check this box /X/.



Item 4.   Ownership.

          This Item 4 is amended and restated in its entirety as follows:

     Each of BI, VII, VI, NAI and Mr.  Sumner M. Redstone  beneficially  own the
one million (1,000,000) shares of Common Stock underlying currently  exercisable
warrants,  representing  approximately 9.37% of the outstanding shares of Common
Stock (based on the number of shares of Common Stock  outstanding  as of October
31, 1998 as reported by the Issuer).

     Due to the  relationship  of the  Reporting  Persons  described  in  Item 2
hereof,  each of the  Reporting  Persons may be deemed to share with each of the
other Reporting Persons power (i) to vote or direct the vote and (ii) to dispose
or to direct  the  disposition  of the  shares of Common  Stock  covered by this
Statement.





                                   Page 5 of 7





Item 5.   Ownership of Five Percent or Less of a Class.

          Not Applicable



Item 6.   Ownership of Five Percent on Behalf of Another Person.

          See Items 2 and 4 hereof



Item 7.   Identification and Classification of the Subsidiary Which Acquired
          the Security Being Reported on By the Parent Holding Company.

          Not Applicable



Item 8.   Identification and Classification of Members of the Group.

          Not Applicable



Item 9.   Notice of Dissolution of Group.

          Not Applicable






                                   Page 6 of 7





Item 10.  Certifications.

     By signing  below we certify that, to the best of our knowledge and belief,
the  securities  referred  to above were not  acquired  and are not held for the
purpose of or with the effect of  changing  or  influencing  the  control of the
issuer of the  securities  and were not acquired and are not held in  connection
with or as a participant in any transaction having that purpose or effect.

     After  reasonable  inquiry and to the best of our knowledge and belief,  we
certify that the information  set forth in this statement is true,  complete and
correct. Pursuant to Rule 13d-1(f)(1),  we agree that this statement is filed on
behalf of each of us.


Date:  February 11, 1999           BLOCKBUSTER INC.


                                   By: /s/Michael D. Fricklas
                                      ----------------------------
                                        Michael D. Fricklas
                                        Senior Vice President




                                   VIACOM INC.


                                   By: /s/Michael D. Fricklas
                                      ----------------------------
                                        Michael D. Fricklas
                                        Senior Vice President and
                                        General Counsel




                                        /s/Sumner M. Redstone
                                   -------------------------------
                                        Sumner M. Redstone,
                                        Individually





                                  Page 7 of 7