video

package
v0.2.1-0...-ac2cde4 Latest Latest
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Published: Jul 6, 2021 License: MIT Imports: 11 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source
var (
	ScalerNearestNeighbor = Scaler(draw.NearestNeighbor)
	ScalerApproxBiLinear  = Scaler(draw.ApproxBiLinear)
	ScalerBiLinear        = Scaler(draw.BiLinear)
	ScalerCatmullRom      = Scaler(draw.CatmullRom)
)

List of scaling algorithms

View Source
var (
	// ScalerFastNearestNeighbor is a CGO version of NearestNeighbor scaler.
	// This is roughly 4-times faster than draw.NearestNeighbor.
	ScalerFastNearestNeighbor = Scaler(&FastNearestNeighbor{})
	// ScalerFastBoxSampling is a CGO implementation of BoxSampling scaler.
	// This is heavyer than NearestNeighbor but keeps detail on down scaling.
	ScalerFastBoxSampling = Scaler(&FastBoxSampling{})
)

List of scaling algorithms

Functions

This section is empty.

Types

type Broadcaster

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

Broadcaster is a specialized video broadcaster.

func NewBroadcaster

func NewBroadcaster(source Reader, config *BroadcasterConfig) *Broadcaster

NewBroadcaster creates a new broadcaster. Source is expected to drop frames when any of the readers is slower than the source.

func (*Broadcaster) NewReader

func (broadcaster *Broadcaster) NewReader(copyFrame bool) Reader

NewReader creates a new reader. Each reader will retrieve the same data from the source. copyFn is used to copy the data from the source to individual readers. Broadcaster uses a small ring buffer, this means that slow readers might miss some data if they're really late and the data is no longer in the ring buffer.

func (*Broadcaster) ReplaceSource

func (broadcaster *Broadcaster) ReplaceSource(source Reader) error

ReplaceSource replaces the underlying source. This operation is thread safe.

func (*Broadcaster) Source

func (broadcaster *Broadcaster) Source() Reader

Source retrieves the underlying source. This operation is thread safe.

type BroadcasterConfig

type BroadcasterConfig struct {
	Core *io.BroadcasterConfig
}

type FastBoxSampling

type FastBoxSampling struct {
}

FastBoxSampling is a CGO version of Box sampling scaler.

func (*FastBoxSampling) Scale

func (f *FastBoxSampling) Scale(dst draw.Image, dr image.Rectangle, src image.Image, sr image.Rectangle, op draw.Op, opts *draw.Options)

Scale implements the draw.Scaler interface.

type FastNearestNeighbor

type FastNearestNeighbor struct {
}

FastNearestNeighbor is a CGO version of NearestNeighbor scaler.

func (*FastNearestNeighbor) Scale

func (f *FastNearestNeighbor) Scale(dst draw.Image, dr image.Rectangle, src image.Image, sr image.Rectangle, op draw.Op, opts *draw.Options)

Scale implements the draw.Scaler interface.

type FrameBuffer

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

FrameBuffer is a buffer that can store any image format.

func NewFrameBuffer

func NewFrameBuffer(initialSize int) *FrameBuffer

NewFrameBuffer creates a new FrameBuffer instance and initialize internal buffer with initialSize

func (*FrameBuffer) Load

func (buff *FrameBuffer) Load() image.Image

Load loads the current owned image

func (*FrameBuffer) StoreCopy

func (buff *FrameBuffer) StoreCopy(src image.Image)

StoreCopy makes a copy of src and store its copy. StoreCopy will reuse as much memory as it can from the previous copies. For example, if StoreCopy is given an image that has the same resolution and format from the previous call, StoreCopy will not allocate extra memory and only copy the content from src to the previous buffer.

type Reader

type Reader interface {
	// Read reads data from the source. The caller is responsible to release the memory that's associated
	// with data by calling the given release function. When err is not nil, the caller MUST NOT call release
	// as data is going to be nil (no memory was given). Otherwise, the caller SHOULD call release after
	// using the data. The caller is NOT REQUIRED to call release, as this is only a part of memory management
	// optimization. If release is not called, the source is forced to allocate a new memory, which also means
	// there will be new allocations during streaming, and old unused memory will become garbage. As a consequence,
	// these garbage will put a lot of pressure to the garbage collector and makes it to run more often and finish
	// slower as the heap memory usage increases and more garbage to collect.
	Read() (img image.Image, release func(), err error)
}

func ToI420

func ToI420(r Reader) Reader

ToI420 converts r to a new reader that will output images in I420 format

func ToRGBA

func ToRGBA(r Reader) Reader

ToRGBA converts r to a new reader that will output images in RGBA format

type ReaderFunc

type ReaderFunc func() (img image.Image, release func(), err error)

func (ReaderFunc) Read

func (rf ReaderFunc) Read() (img image.Image, release func(), err error)

type Scaler

type Scaler draw.Scaler

Scaler represents scaling algorithm

type TransformFunc

type TransformFunc func(r Reader) Reader

TransformFunc produces a new Reader that will produces a transformed video

func DetectChanges

func DetectChanges(interval time.Duration, fpsDiffTolerance float64, onChange func(prop.Media)) TransformFunc

DetectChanges will detect frame and video property changes. For video property detection, since it's time related, interval will be used to determine the sample rate.

func Merge

func Merge(transforms ...TransformFunc) TransformFunc

Merge merges transforms and produces a new TransformFunc that will execute transforms in order

func Scale

func Scale(width, height int, scaler Scaler) TransformFunc

Scale returns video scaling transform. Setting scaler=nil to use default scaler. (ScalerNearestNeighbor) Negative width or height value will keep the aspect ratio of incoming image.

Note: computation cost to scale YCbCr format is 10 times higher than RGB due to the implementation in x/image/draw package.

func Throttle

func Throttle(rate float32) TransformFunc

Throttle returns video throttling transform. This transform drops some of the incoming frames to achieve given framerate in fps.

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