<?xml version="1.0" encoding="utf-8"?>
<PRONOM-Report xmlns="http://pronom.nationalarchives.gov.uk">
  <report_format_detail>
    <FileFormat>
      <FormatID>1740</FormatID>
      <FormatName>Animated Portable Network Graphics</FormatName>
      <FormatVersion>
      </FormatVersion>
      <FormatAliases>APNG</FormatAliases>
      <FormatFamilies>
      </FormatFamilies>
      <FormatTypes>Image (Raster)</FormatTypes>
      <FormatDisclosure>
      </FormatDisclosure>
      <FormatDescription>APNG is an extension of the PNG format, adding support for animated images. It is intended to be a replacement for simple animated images that have traditionally used the GIF format, while adding support for 24-bit images and 8-bit transparency. APNG is intended as a simpler alternative to MNG.

APNG is backwards-compatible with PNG; any PNG decoder should be able to ignore the APNG-specific chunks and display a single image.</FormatDescription>
      <BinaryFileFormat>
      </BinaryFileFormat>
      <ByteOrders>
      </ByteOrders>
      <ReleaseDate>
      </ReleaseDate>
      <WithdrawnDate>
      </WithdrawnDate>
      <ProvenanceSourceID>1</ProvenanceSourceID>
      <ProvenanceName>Digital Preservation Department / The National Archives</ProvenanceName>
      <ProvenanceSourceDate>11 Jul 2016</ProvenanceSourceDate>
      <ProvenanceDescription>
      </ProvenanceDescription>
      <LastUpdatedDate>11 Jul 2016</LastUpdatedDate>
      <FormatNote>
      </FormatNote>
      <FormatRisk>
      </FormatRisk>
      <TechnicalEnvironment>
      </TechnicalEnvironment>
      <FileFormatIdentifier>
        <Identifier>fmt/935</Identifier>
        <IdentifierType>PUID</IdentifierType>
      </FileFormatIdentifier>
      <FileFormatIdentifier>
        <Identifier>image/vnd.mozilla.apng</Identifier>
        <IdentifierType>MIME</IdentifierType>
      </FileFormatIdentifier>
      <ExternalSignature>
        <ExternalSignatureID>1890</ExternalSignatureID>
        <Signature>png</Signature>
        <SignatureType>File extension</SignatureType>
      </ExternalSignature>
      <ExternalSignature>
        <ExternalSignatureID>1891</ExternalSignatureID>
        <Signature>apng</Signature>
        <SignatureType>File extension</SignatureType>
      </ExternalSignature>
      <InternalSignature>
        <SignatureID>1279</SignatureID>
        <SignatureName>APNG</SignatureName>
        <SignatureNote>Signature + IHDR and acTL chunks at BOF, IEND chunk at EOF
Specification: https://wiki.mozilla.org/APNG_Specification</SignatureNote>
        <ByteSequence>
          <ByteSequenceID>1551</ByteSequenceID>
          <PositionType>Absolute from BOF</PositionType>
          <Offset>0</Offset>
          <MaxOffset>0</MaxOffset>
          <IndirectOffsetLocation>
          </IndirectOffsetLocation>
          <IndirectOffsetLength>
          </IndirectOffsetLength>
          <Endianness>
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          <ByteSequenceValue>89504E470D0A1A0A0000000D49484452*6163544C</ByteSequenceValue>
        </ByteSequence>
        <ByteSequence>
          <ByteSequenceID>1552</ByteSequenceID>
          <PositionType>Absolute from EOF</PositionType>
          <Offset>0</Offset>
          <MaxOffset>0</MaxOffset>
          <IndirectOffsetLocation>
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          <IndirectOffsetLength>
          </IndirectOffsetLength>
          <Endianness>
          </Endianness>
          <ByteSequenceValue>0000000049454E44AE426082</ByteSequenceValue>
        </ByteSequence>
      </InternalSignature>
      <RelatedFormat>
        <RelationshipType>Has priority over</RelationshipType>
        <RelatedFormatID>664</RelatedFormatID>
        <RelatedFormatName>Portable Network Graphics</RelatedFormatName>
        <RelatedFormatVersion>1.0</RelatedFormatVersion>
      </RelatedFormat>
    </FileFormat>
    <SearchCriteria>Criteria</SearchCriteria>
  </report_format_detail>
</PRONOM-Report>
