 Type Box ('schm') with a scheme_type field set to a value of
        <code>'cenc'</code> or <code>'cbcs'</code> [[CENC]].
      </p>
    </section>

    <section id="detect-encrypted-blocks">
      <h2>Detecting Encrypted Blocks</h2>
      <p>
        For the purposes of the [=Encrypted Block Encountered=] algorithm,
        encrypted blocks are identified as follows.
      </p>
      <p>
        The encrypted block is a sample. Determining whether a sample is
        encrypted depends on the corresponding