video

package
v0.0.0-...-e78e2ff Latest Latest
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Published: Jul 28, 2018 License: BSD-3-Clause Imports: 3 Imported by: 1

Documentation

Index

Constants

View Source
const (

	// TileSideLength is the number of pixel per side of a square frame tile
	TileSideLength = 4
	// PixelPerTile is the number of pixel within one frame tile
	PixelPerTile = TileSideLength * TileSideLength
)
View Source
const (
	CtrlColorTile2ColorsStatic  = ControlType(0)
	CtrlColorTile2ColorsMasked  = ControlType(1)
	CtrlColorTile4ColorsMasked  = ControlType(2)
	CtrlColorTile8ColorsMasked  = ControlType(3)
	CtrlColorTile16ColorsMasked = ControlType(4)

	CtrlSkip = ControlType(5)

	CtrlRepeatPrevious = ControlType(6)
	CtrlUnknown        = ControlType(7)
)

Variables

View Source
var FormatError = fmt.Errorf("Format Error")

Functions

func PackControlWords

func PackControlWords(words []ControlWord) []byte

PackControlWords packs and encodes the given words into a byte stream.

Types

type BitstreamReader

type BitstreamReader struct {
	// contains filtered or unexported fields
}

BitstreamReader is a utility to read big-endian integer values of arbitrary bit size from a bitstream.

func NewBitstreamReader

func NewBitstreamReader(data []byte) *BitstreamReader

NewBitsreamReader returns a new instance of a bistream reader using the provided byte slice as source.

func (*BitstreamReader) Advance

func (reader *BitstreamReader) Advance(bits int)

Advance skips the provided amount of bits and puts the current position there. Successive read operations will return values from the new position. It is possible to advance beyond the available length.

This function panics when advancing with negative values.

func (*BitstreamReader) Exhausted

func (reader *BitstreamReader) Exhausted() bool

Exhausted returns true if the current position is at or beyond the possible length. Reading an exhausted stream yields only zeroes.

func (*BitstreamReader) Read

func (reader *BitstreamReader) Read(bits int) (result uint32)

Read returns a value with the requested bit size, right aligned, as a uint32. Reading does not advance the current position. A successful read of a certain size will return the same value when called repeatedly with the same parameter. Reading is possible beyond the available size. For the missing bits, a value of 0 is provided.

The function panics when reading more than 32 bits.

type ControlType

type ControlType byte

ControlType defines how to interpret a ControlWord

type ControlWord

type ControlWord uint32

ControlWord describes the current compression action.

func UnpackControlWords

func UnpackControlWords(data []byte) (words []ControlWord, err error)

UnpackControlWords reads from an encoded string of bytes a series of packed control words. If all is OK, the control words are returned. If the function returns an error, something could not be read/decoded properly.

func (ControlWord) Count

func (word ControlWord) Count() int

Count returns the count value of the control

func (ControlWord) IsLongOffset

func (word ControlWord) IsLongOffset() bool

IsLongOffset returns true if Count() returns 0.

func (ControlWord) LongOffset

func (word ControlWord) LongOffset() uint32

LongOffset returns the long offset value. Only relevant if IsLongOffset() returns true.

func (ControlWord) Packed

func (word ControlWord) Packed(times int) PackedControlWord

Packed returns the control word packed in a PackedControlWord with the given number of times.

func (ControlWord) Parameter

func (word ControlWord) Parameter() uint32

Parameter returns the type specific parameter value.

func (ControlWord) Type

func (word ControlWord) Type() ControlType

Type returns the type of the control. Only relevant if IsLongOffset() returns false.

type FrameDecoder

type FrameDecoder struct {
	// contains filtered or unexported fields
}

FrameDecoder is for decoding compressed frames with the help of data streams. A new instance of a decoder is created with a FrameDecoderBuilder.

func (*FrameDecoder) Decode

func (decoder *FrameDecoder) Decode(bitstreamData []byte, maskstreamData []byte)

Decode reads the provided streams to paint a frame.

type FrameDecoderBuilder

type FrameDecoderBuilder struct {
	// contains filtered or unexported fields
}

FrameDecoderBuilder implements the builder pattern for creating new instances of FrameDecoder. This builder can be reused during the processing of a movie. Every Build() call creates a new instance.

func NewFrameDecoderBuilder

func NewFrameDecoderBuilder(width, height int) *FrameDecoderBuilder

NewFrameDecoderBuilder returns a new instance of a builder with given initial values.

func (*FrameDecoderBuilder) Build

func (builder *FrameDecoderBuilder) Build() *FrameDecoder

Build creates a new instance of a decoder with the most recent parameters.

func (*FrameDecoderBuilder) ForStandardFrame

func (builder *FrameDecoderBuilder) ForStandardFrame(frame []byte, stride int)

ForStandardFrame registers the frame buffer and sets the standard coloring method.

func (*FrameDecoderBuilder) WithControlWords

func (builder *FrameDecoderBuilder) WithControlWords(words []ControlWord)

WithControlWords registers the new word dictionary.

func (*FrameDecoderBuilder) WithPaletteLookupList

func (builder *FrameDecoderBuilder) WithPaletteLookupList(list []byte)

WithPaletteLookupList registers the new list.

type MaskstreamReader

type MaskstreamReader struct {
	// contains filtered or unexported fields
}

MaskstreamReader reads mask integers from a byte array.

func NewMaskstreamReader

func NewMaskstreamReader(source []byte) *MaskstreamReader

NewMaskstreamReader returns a new reader instance for given source.

func (*MaskstreamReader) Read

func (reader *MaskstreamReader) Read(bytes int) (value uint64)

Read returns a mask integer of given byte length from the current position. If the current position is at or beyond the available size, 0x00 is assumed for the missing bytes.

Reading more than 8, or less than 0, bytes panics.

type PackedControlWord

type PackedControlWord uint32

PackedControlWord contains a ControlWord together with a count value of occurrences.

func (PackedControlWord) Times

func (packed PackedControlWord) Times() int

Times returns the amount of occurrences of the contained control word.

func (PackedControlWord) Value

func (packed PackedControlWord) Value() ControlWord

Value returns the control word value.

type TileColorFunction

type TileColorFunction func(hTile int, vTile int, lookupArray []byte, mask uint64, indexBitSize uint64)

TileColorFunction is one which shall color the pixel of a video frame tile using the provided values. mask is a packed field of 16 indices, each with a length of indexBitSize. These indices point into a value of lookupArray.

func StandardTileColorer

func StandardTileColorer(frame []byte, stride int) TileColorFunction

StandardTileColorer returns a TileColorFunction for given frame buffer.

This colorer iterates over all pixel of a tile. It sets the pixel value if the corresponding palette value is > 0x00.

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