tor-browser

The Tor Browser
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bipbop-frag-cenc.xml (2197B)


      1 <?xml version="1.0" encoding="UTF-8"?>
      2 
      3 <!--
      4  This XML file describes the encryption applied to |bipbop-cenc*|. To
      5  generate the bipbop-cenc files, run the following commands:
      6 
      7  Encrypt bipbop-no-edts.mp4 with the keys specified in this file,
      8  and output to |bipbop-cenc-{video,audio}.mp4|
      9    MP4Box -crypt bipbop-frag-cenc.xml -rem 2 -out bipbop-cenc-video.mp4 bipbop-no-edts.mp4
     10    MP4Box -crypt bipbop-frag-cenc.xml -rem 1 -out bipbop-cenc-audio.mp4 bipbop-no-edts.mp4
     11 
     12  Fragment |bipbop-cenc-*.mp4| into 500ms segments:
     13    MP4Box -dash 500 -rap -segment-name bipbop-cenc-video -subsegs-per-sidx 5 bipbop-cenc-video.mp4
     14    MP4Box -dash 500 -rap -segment-name bipbop-cenc-audio -subsegs-per-sidx 5 bipbop-cenc-audio.mp4
     15 
     16  The above command will generate a set of fragments in |bipbop-cenc-{video,audio}*.m4s
     17  and |bipbop-cenc-{video,audio}init.mp4| containing just the init segment.
     18 
     19  To cut down the duration, we throw out all but the first 3 audio & 2 video segments:
     20    rm bipbop-cenc-audio{[^123],[123][^.]}.m4s
     21    rm bipbop-cenc-video{[^12],[12][^.]}.m4s
     22 
     23  MP4Box will also have generated some *.mpd files we don't need:
     24    rm bipbop-cenc-*.mpd
     25 
     26  Delete intermediate encrypted files:
     27    rm bipbop-cenc-{audio,video}.mp4
     28 -->
     29 
     30 <GPACDRM type="CENC AES-CTR">
     31 
     32  <DRMInfo type="pssh" version="1">
     33    <!--
     34    SystemID specified in
     35    https://dvcs.w3.org/hg/html-media/raw-file/tip/encrypted-media/cenc-format.html
     36    -->
     37    <BS ID128="1077efecc0b24d02ace33c1e52e2fb4b" />
     38    <!-- Number of KeyIDs = 2 -->
     39    <BS bits="32" value="2" />
     40    <!-- KeyID -->
     41    <BS ID128="0x7e571d037e571d037e571d037e571d03" />
     42    <BS ID128="0x7e571d047e571d047e571d047e571d04" />
     43  </DRMInfo>
     44 
     45  <CrypTrack trackID="1" isEncrypted="1" IV_size="16" saiSavedBox="senc"
     46    first_IV="0x00000000000000000000000000000000">
     47    <key KID="0x7e571d037e571d037e571d037e571d03"
     48      value="0x7e5733337e5733337e5733337e573333" />
     49  </CrypTrack>
     50 
     51  <CrypTrack trackID="2" isEncrypted="1" IV_size="16" saiSavedBox="senc"
     52    first_IV="0x00000000000000000000000000000000">
     53    <key KID="0x7e571d047e571d047e571d047e571d04"
     54      value="0x7e5744447e5744447e5744447e574444" />
     55  </CrypTrack>
     56 
     57 </GPACDRM>