how to convert binarystring to base64

i have this binarystring in this format:

%PDF-1.3
%âãÏÓ
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<</Linearized 1/L 7945/O 9/E 3524/N 1/T 7656/H [ 451 137]>>
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13 0 obj
<</DecodeParms<</Columns 4/Predictor 12>>/Filter/FlateDecode/ID[<4DC91A1875A6D707AEC203BB021C93A0><F6C92B368A8A13408457A1D395A37EB9>]/Index[7 21]/Info 6 0 R/Length 52/Prev 7657/Root 8 0 R/Size 28/Type/XRef/W[1 2 1]>>stream
hÞbbd``b`² ±H0§ 6G ñå#Ã4,#¹ÄÆ_L¤ð
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startxref
0
%%EOF

27 0 obj
<</Filter/FlateDecode/I 69/Length 58/S 38>>stream
hÞb```a``üÏÜ6¨¬$ËѬ,ÆÅ
ÜÜÓt&¬8ÌZ-R,¿â
endstream
endobj
8 0 obj
<</Metadata 1 0 R/Pages 5 0 R/Type/Catalog>>
endobj
9 0 obj
<</Contents 11 0 R/CropBox[0 0 595 842]/MediaBox[0 0 595 842]/Parent 5 0 R/Resources 14 0 R/Rotate 0/Type/Page>>
endobj
10 0 obj
<</Filter/FlateDecode/First 94/Length 773/N 13/Type/ObjStm>>stream
hÞ¼TmoÚ0þ+þàØq"UHÐ}®ÒZ¡&[?DùBW£ÿ~w  .µ+¥ÒÆÌùåî|¾ç¹ã0Âá~&Ü'"¬"&~Æç0`FTÈÆà$ &gZá­æDH°b!à(°Æ$¹¸ UQÕÑ&:\4
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CÅTJV¹5³*/mÒmxá!DBÑÜ<eEcht9¦Æ÷ôfaJ:Û¿lÌ>?£è_åOO¦6åÜ4    §ÏEalºS,çÕ"/­Þ$k&F/ëǪx=DX1UÑó£E#´ä4®~9(ÂwIÅ3´o:9DDB¦ :ï&_®,aôÊtûÁ9ٲƴVIµM>Ðgài$Ì`2HÛÓ»lmè¸Î³b0©`ÅmLolVäóq¹,ø¬Yÿ*zû0ðª:ßت>|Ý÷Fúã²É_×Ó¼nìå*«]|{wHl|ðl§Á¹¿ONýlb¥Ö\/ìªIFJ~íkiò*}ÎßÐñ}ý¡¥üÖº/»¥î/[-ÏóÒ>ÀAÈßØwËÀÊG¬"¬±S0¦{ÇùÚ4wæ÷}µÎÊYôÊìcRÿvtЭå)@«ÃdCcÚÚѦVíÿO&Aíf{¨}uÐ;ÈB)ßа«Ø¡ÄÈp}£O
Ãíãؽ¨ z'»¸#ÿëÓ>K¿Ôe|$ÊÐÓÇ]æ|ê9óóç4Nj,x-É0è¤Ô]IrÁ|Ì x¿$Û¾Ùeæ(E®>Ó&ÿé÷¼Ü©£büRbݧè©=÷}Ì\qºÿ®¨û1îô`
Ñ£9bWÒ@Æ?>Ð`ñ
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<</Filter/FlateDecode/Length 1530>>stream
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z(}ÕçË­kxPëðåäq.µú³ÞâS]á4oC!DI!£lè¹Aqz¤Ò+í9lÞa{gß,ù~ Ê.Ö.îC¬ypd+    ­L½£0
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12 0 obj
<</Filter/FlateDecode/Length 208>>stream
H0T½Â0÷>&GCÚÎUX:ð#
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endstream
endobj
1 0 obj
<</Length 3656/Subtype/XML/Type/Metadata>>stream
<?xpacket begin="" id="W5M0MpCehiHzreSzNTczkc9d"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 4.2.1-c043 52.372728, 2009/01/18-15:08:04        ">
   <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
      <rdf:Description rdf:about=""
            xmlns:dc="http://purl.org/dc/elements/1.1/">
         <dc:format>application/pdf</dc:format>
         <dc:creator>
            <rdf:Seq>
               <rdf:li>cdaily</rdf:li>
            </rdf:Seq>
         </dc:creator>
         <dc:title>
            <rdf:Alt>
               <rdf:li xml:lang="x-default">This is a test PDF file</rdf:li>
            </rdf:Alt>
         </dc:title>
      </rdf:Description>
      <rdf:Description rdf:about=""
            xmlns:xmp="http://ns.adobe.com/xap/1.0/">
         <xmp:CreateDate>2000-06-29T10:21:08+11:00</xmp:CreateDate>
         <xmp:CreatorTool>Microsoft Word 8.0</xmp:CreatorTool>
         <xmp:ModifyDate>2013-10-28T15:24:13-04:00</xmp:ModifyDate>
         <xmp:MetadataDate>2013-10-28T15:24:13-04:00</xmp:MetadataDate>
      </rdf:Description>
      <rdf:Description rdf:about=""
            xmlns:pdf="http://ns.adobe.com/pdf/1.3/">
         <pdf:Producer>Acrobat Distiller 4.0 for Windows</pdf:Producer>
      </rdf:Description>
      <rdf:Description rdf:about=""
            xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/">
         <xmpMM:DocumentID>uuid:0805e221-80a8-459e-a522-635ed5c1e2e6</xmpMM:DocumentID>
         <xmpMM:InstanceID>uuid:62d6ae6d-43c4-472d-9b28-7c4add8f9e46</xmpMM:InstanceID>
      </rdf:Description>
   </rdf:RDF>
</x:xmpmeta>





















<?xpacket end="w"?>
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<</Filter/FlateDecode/First 4/Length 48/N 1/Type/ObjStm>>stream
hÞ2U0P°±ÑwÎ/Í+Q0Ô÷ÎL)}¶`Åê!T¤ê$¦§ÛÙÖw¬
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<</Filter/FlateDecode/First 4/Length 167/N 1/Type/ObjStm>>stream
hÞ<ËÁ
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<</DecodeParms<</Columns 3/Predictor 12>>/Filter/FlateDecode/ID[<4DC91A1875A6D707AEC203BB021C93A0><F6C92B368A8A13408457A1D395A37EB9>]/Info 6 0 R/Length 37/Root 8 0 R/Size 7/Type/XRef/W[1 2 0]>>stream
hÞbb```bä=ÂÄÀ?"0¡!0&0ñ±$Í`*Y
endstream
endobj
startxref
116
%%EOF

and i would like to convert it to base64. However i am not able to use btoa(BINARYSTRING) to convert, not sure why. Is there any way i could convert it? i have tried many different methods including btoa(unescape(BINARYSTRING)) and btoa(unescape(encodeURIComponent(BINARYSTRING))). both doesnt seem to give a encoded base64 result back.