Dicom.TransferSyntax (Dicom v0.9.1)

Transfer Syntax definitions and properties.

A Transfer Syntax specifies how DICOM data is encoded: byte order, whether VR is explicit or implicit, and pixel data compression.

Registers 49 DICOM transfer syntaxes currently tracked by this library (34 active + 15 retired). Unknown transfer syntaxes are rejected by default — use encoding/2 with lenient: true to fall back to Explicit VR Little Endian for unrecognized UIDs.

Reference: DICOM PS3.5 Section 10, PS3.6 Table A-1.

Summary

Types

endianness()

t()

vr_encoding()

Functions

active()

Returns only active (non-retired) transfer syntaxes.

all()

Returns all registered transfer syntaxes.

compressed?(uid)

Returns true if the transfer syntax uses compressed pixel data.

encoding(uid, opts \\ [])

Returns the VR encoding and endianness for a given transfer syntax UID.

extract_uid(file_meta)

Extracts the transfer syntax UID from a file meta elements map.

fragmentable?(uid)

Returns true if the transfer syntax uses fragmentable encapsulation.

from_uid(uid)

Returns the transfer syntax definition for the given UID.

implicit_vr?(uid)

Returns true if the transfer syntax uses implicit VR encoding.

known?(uid)

Returns true if the given UID is a known transfer syntax.

retired?(uid)

Returns true if the transfer syntax is retired.

Types

endianness()

@type endianness() :: :little | :big

t()

@type t() :: %Dicom.TransferSyntax{
  compressed: boolean(),
  endianness: endianness(),
  fragmentable: boolean(),
  name: String.t(),
  retired: boolean(),
  uid: String.t(),
  vr_encoding: vr_encoding()
}

vr_encoding()

@type vr_encoding() :: :implicit | :explicit

Functions

active()

@spec active() :: [t()]

Returns only active (non-retired) transfer syntaxes.

all()

@spec all() :: [t()]

Returns all registered transfer syntaxes.

compressed?(uid)

@spec compressed?(String.t()) :: boolean()

Returns true if the transfer syntax uses compressed pixel data.

encoding(uid, opts \\ [])

@spec encoding(
  String.t(),
  keyword()
) :: {:ok, {vr_encoding(), endianness()}} | {:error, :unknown_transfer_syntax}

Returns the VR encoding and endianness for a given transfer syntax UID.

Returns {:ok, {vr_encoding, endianness}} for known transfer syntaxes, or {:error, :unknown_transfer_syntax} for unknown UIDs.

Options

lenient: true — falls back to {:ok, {:explicit, :little}} for unknown UIDs instead of returning an error. Use this only when you need to attempt parsing files with unrecognized private or future transfer syntaxes.

extract_uid(file_meta)

@spec extract_uid(%{required(Dicom.Tag.t()) => Dicom.DataElement.t()}) :: String.t()

Extracts the transfer syntax UID from a file meta elements map.

Falls back to Implicit VR Little Endian if the tag is absent.

fragmentable?(uid)

@spec fragmentable?(String.t()) :: boolean()

Returns true if the transfer syntax uses fragmentable encapsulation.

Fragmentable transfer syntaxes (MPEG, HEVC) may have pixel data fragments that do not correspond one-to-one with frames.

from_uid(uid)

@spec from_uid(String.t()) :: {:ok, t()} | {:error, :unknown_transfer_syntax}

Returns the transfer syntax definition for the given UID.

implicit_vr?(uid)

@spec implicit_vr?(String.t()) :: boolean()

Returns true if the transfer syntax uses implicit VR encoding.

known?(uid)

@spec known?(String.t()) :: boolean()

Returns true if the given UID is a known transfer syntax.

retired?(uid)

@spec retired?(String.t()) :: boolean()

Returns true if the transfer syntax is retired.