encaps

Documentation

Overview

Package encaps parses DICOM encapsulated (compressed) pixel data. Behaviour aligns with pydicom.encaps.

Index

• func CountFragments(fragmentData []byte, littleEndian bool) (int, error)
• func Encapsulate(frames [][]byte, fragmentsPerFrame int, hasBOT bool) ([]byte, error)
• func EncapsulateExtended(frames [][]byte) (pixelData, offsets, lengths []byte, err error)
• func FragmentFrame(frame []byte, nrFragments int) ([][]byte, error)
• func GenerateFragmentedFrames(pixelData []byte, opts FramesOptions) ([][][]byte, error)
• func GenerateFrames(pixelData []byte, opts FramesOptions) ([][]byte, error)
• func GetFrame(pixelData []byte, index int, opts FramesOptions) ([]byte, error)
• func ItemizeFragment(fragment []byte) []byte
• func ParseBasicOffsets(buf []byte, littleEndian bool) (offsets []uint32, rest []byte, err error)
• type ExtendedOffsetTable
• type FramesOptions

Functions

func CountFragments

func CountFragments(fragmentData []byte, littleEndian bool) (int, error)

CountFragments returns the number of fragment items in encapsulated pixel data starting at the first fragment item (after the Basic Offset Table, if any).

func Encapsulate

func Encapsulate(frames [][]byte, fragmentsPerFrame int, hasBOT bool) ([]byte, error)

Encapsulate returns encapsulated pixel data for compressed frames. Mirrors pydicom.encaps.encapsulate. Does not append the sequence delimiter; writers emit that for undefined-length OB.

fragmentsPerFrame defaults to 1 when <= 0.

func EncapsulateExtended

func EncapsulateExtended(frames [][]byte) (pixelData, offsets, lengths []byte, err error)

EncapsulateExtended returns encapsulated frames (empty BOT) plus Extended Offset Table and Lengths element values. Mirrors pydicom.encaps.encapsulate_extended.

func FragmentFrame

func FragmentFrame(frame []byte, nrFragments int) ([][]byte, error)

FragmentFrame splits frame into nrFragments even-sized pieces. The last fragment is padded with 0x00 when needed. Mirrors pydicom fragment_frame.

func GenerateFragmentedFrames

func GenerateFragmentedFrames(pixelData []byte, opts FramesOptions) ([][][]byte, error)

GenerateFragmentedFrames splits encapsulated pixel data into per-frame fragment groups.

func GenerateFrames

func GenerateFrames(pixelData []byte, opts FramesOptions) ([][]byte, error)

GenerateFrames returns one concatenated encoded frame per logical image frame.

func GetFrame

func GetFrame(pixelData []byte, index int, opts FramesOptions) ([]byte, error)

GetFrame returns the encoded data for the frame at index.

func ItemizeFragment

func ItemizeFragment(fragment []byte) []byte

ItemizeFragment wraps a fragment as a DICOM Item (FFFE,E000) + length + data.

func ParseBasicOffsets

func ParseBasicOffsets(buf []byte, littleEndian bool) (offsets []uint32, rest []byte, err error)

ParseBasicOffsets reads the Basic Offset Table at the start of encapsulated pixel data. The buffer is consumed through the end of the BOT item; remaining data begins at the first fragment item tag.

Types

type ExtendedOffsetTable

type ExtendedOffsetTable struct {
	Offsets []uint64
	Lengths []uint64
}

ExtendedOffsetTable holds (7FE0,0001) and (7FE0,0002) values.

type FramesOptions

type FramesOptions struct {
	NumberOfFrames  int
	ExtendedOffsets *ExtendedOffsetTable
	LittleEndian    bool // encapsulated item tags use little endian (DICOM default)
}

FramesOptions configures frame generation from encapsulated pixel data.