<?xml version="1.0" encoding="utf-8"?>
<PRONOM-Report xmlns="http://pronom.nationalarchives.gov.uk">
  <report_format_detail>
    <FileFormat>
      <FormatID>1102</FormatID>
      <FormatName>Adaptive Multi-Rate Audio</FormatName>
      <FormatVersion>
      </FormatVersion>
      <FormatAliases>AMR-NB, GSM-AMR</FormatAliases>
      <FormatFamilies>
      </FormatFamilies>
      <FormatTypes>Audio</FormatTypes>
      <FormatDisclosure>
      </FormatDisclosure>
      <FormatDescription>The Adaptive Multi-Rate (AMR or AMR-NB or GSM-AMR) audio codec is an audio compression format optimized for speech coding. AMR speech codec consists of a multi-rate narrowband speech codec that encodes narrowband (200–3400 Hz) signals at variable bit rates ranging from 4.75 to 12.2 kbit/s with toll quality speech starting at 7.4 kbit/s.</FormatDescription>
      <BinaryFileFormat>Text</BinaryFileFormat>
      <ByteOrders>
      </ByteOrders>
      <ReleaseDate>
      </ReleaseDate>
      <WithdrawnDate>
      </WithdrawnDate>
      <ProvenanceSourceID>1</ProvenanceSourceID>
      <ProvenanceName>Digital Preservation Department / The National Archives</ProvenanceName>
      <ProvenanceSourceDate>17 Jun 2011</ProvenanceSourceDate>
      <ProvenanceDescription>
      </ProvenanceDescription>
      <LastUpdatedDate>17 Jun 2011</LastUpdatedDate>
      <FormatNote>
      </FormatNote>
      <FormatRisk>
      </FormatRisk>
      <TechnicalEnvironment>
      </TechnicalEnvironment>
      <FileFormatIdentifier>
        <Identifier>audio/amr</Identifier>
        <IdentifierType>MIME</IdentifierType>
      </FileFormatIdentifier>
      <FileFormatIdentifier>
        <Identifier>fmt/356</Identifier>
        <IdentifierType>PUID</IdentifierType>
      </FileFormatIdentifier>
      <ExternalSignature>
        <ExternalSignatureID>1124</ExternalSignatureID>
        <Signature>amr</Signature>
        <SignatureType>File extension</SignatureType>
      </ExternalSignature>
      <InternalSignature>
        <SignatureID>524</SignatureID>
        <SignatureName>Adaptive Multi-Rate Audio</SignatureName>
        <SignatureNote>Header (ASCII): #!AMR.</SignatureNote>
        <ByteSequence>
          <ByteSequenceID>646</ByteSequenceID>
          <PositionType>Absolute from BOF</PositionType>
          <Offset>0</Offset>
          <MaxOffset>
          </MaxOffset>
          <IndirectOffsetLocation>
          </IndirectOffsetLocation>
          <IndirectOffsetLength>
          </IndirectOffsetLength>
          <Endianness>
          </Endianness>
          <ByteSequenceValue>2321414D520A</ByteSequenceValue>
        </ByteSequence>
      </InternalSignature>
      <RelatedFormat>
        <RelationshipType>Can be contained by</RelationshipType>
        <RelatedFormatID>1103</RelatedFormatID>
        <RelatedFormatName>3GPP Audio/Video File</RelatedFormatName>
        <RelatedFormatVersion>
        </RelatedFormatVersion>
      </RelatedFormat>
    </FileFormat>
    <SearchCriteria>Criteria</SearchCriteria>
  </report_format_detail>
</PRONOM-Report>
