swscale

package
v0.0.5 Latest Latest
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 Go to latest Published: Jan 21, 2024 License: LGPL-2.1 Imports: 4 Imported by: 0

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Index

Constants

View Source 
const (
	SWS_FAST_BILINEAR = C.SWS_FAST_BILINEAR
	SWS_BILINEAR      = C.SWS_BILINEAR
	SWS_BICUBIC       = C.SWS_BICUBIC
	SWS_X             = C.SWS_X
	SWS_POINT         = C.SWS_POINT
	SWS_AREA          = C.SWS_AREA
	SWS_BICUBLIN      = C.SWS_BICUBLIN
	SWS_GAUSS         = C.SWS_GAUSS
	SWS_SINC          = C.SWS_SINC
	SWS_LANCZOS       = C.SWS_LANCZOS
	SWS_SPLINE        = C.SWS_SPLINE
)

values for the flags, the stuff on the command line is different

View Source 
const (
	SWS_SRC_V_CHR_DROP_MASK  = C.SWS_SRC_V_CHR_DROP_MASK
	SWS_SRC_V_CHR_DROP_SHIFT = C.SWS_SRC_V_CHR_DROP_SHIFT
)
View Source 
const (
	SWS_FULL_CHR_H_INP  = C.SWS_FULL_CHR_H_INP
	SWS_DIRECT_BGR      = C.SWS_DIRECT_BGR
	SWS_ACCURATE_RND    = C.SWS_ACCURATE_RND
	SWS_BITEXACT        = C.SWS_BITEXACT
	SWS_ERROR_DIFFUSION = C.SWS_ERROR_DIFFUSION
)

input subsampling info

View Source 
const (
	SWS_CS_ITU709    = C.SWS_CS_ITU709
	SWS_CS_FCC       = C.SWS_CS_FCC
	SWS_CS_ITU601    = C.SWS_CS_ITU601
	SWS_CS_ITU624    = C.SWS_CS_ITU624
	SWS_CS_SMPTE170M = C.SWS_CS_SMPTE170M
	SWS_CS_SMPTE240M = C.SWS_CS_SMPTE240M
	SWS_CS_DEFAULT   = C.SWS_CS_DEFAULT
	SWS_CS_BT2020    = C.SWS_CS_BT2020
)
View Source 
const LIBSWSCALE_BUILD = C.LIBSWSCALE_BUILD
View Source 
const LIBSWSCALE_IDENT = C.LIBSWSCALE_IDENT
View Source 
const LIBSWSCALE_VERSION_INT = C.LIBSWSCALE_VERSION_INT
View Source 
const LIBSWSCALE_VERSION_MAJOR = C.LIBSWSCALE_VERSION_MAJOR
View Source 
const LIBSWSCALE_VERSION_MICRO = C.LIBSWSCALE_VERSION_MICRO
View Source 
const LIBSWSCALE_VERSION_MINOR = C.LIBSWSCALE_VERSION_MINOR
View Source 
const SWS_FULL_CHR_H_INT = C.SWS_FULL_CHR_H_INT

the following 3 flags are not completely implemented internal chrominance subsampling info

View Source 
const SWS_MAX_REDUCE_CUTOFF = C.SWS_MAX_REDUCE_CUTOFF
View Source 
const SWS_PARAM_DEFAULT = C.SWS_PARAM_DEFAULT
View Source 
const SWS_PRINT_INFO = C.SWS_PRINT_INFO

Variables

This section is empty.

Functions

func SwsConvertPalette8ToPacked24 

func SwsConvertPalette8ToPacked24(src unsafe.Pointer, dst unsafe.Pointer, numPixels int, palette *ctypes.UInt8)

*

  • Convert an 8-bit paletted frame into a frame with a color depth of 24 bits. *
  • With the palette format "ABCD", the destination frame ends up with the format "ABC". *
  • @param src source frame buffer
  • @param dst destination frame buffer
  • @param num_pixels number of pixels to convert
  • @param palette array with [256] entries, which must match color arrangement (RGB or BGR) of src

func SwsConvertPalette8ToPacked32 

func SwsConvertPalette8ToPacked32(src unsafe.Pointer, dst unsafe.Pointer, numPixels int, palette *ctypes.UInt8)

*

  • Convert an 8-bit paletted frame into a frame with a color depth of 32 bits. *
  • The output frame will have the same packed format as the palette. *
  • @param src source frame buffer
  • @param dst destination frame buffer
  • @param num_pixels number of pixels to convert
  • @param palette array with [256] entries, which must match color arrangement (RGB or BGR) of src

func SwsFrameEnd 

func SwsFrameEnd(c *CSwsContext)

*

  • Finish the scaling process for a pair of source/destination frames previously
  • submitted with sws_frame_start(). Must be called after all sws_send_slice()
  • and sws_receive_slice() calls are done, before any new sws_frame_start()
  • calls. *
  • @param c The scaling context

func SwsFrameStart 

func SwsFrameStart(c *CSwsContext, dst *avutil.CAVFrame, src *avutil.CAVFrame) int

*

  • Initialize the scaling process for a given pair of source/destination frames.
  • Must be called before any calls to sws_send_slice() and sws_receive_slice(). *
  • This function will retain references to src and dst, so they must both use
  • refcounted buffers (if allocated by the caller, in case of dst). *
  • @param c The scaling context
  • @param dst The destination frame. *
  • The data buffers may either be already allocated by the caller or
  • left clear, in which case they will be allocated by the scaler.
  • The latter may have performance advantages - e.g. in certain cases
  • some output planes may be references to input planes, rather than
  • copies. *
  • Output data will be written into this frame in successful
  • sws_receive_slice() calls.
  • @param src The source frame. The data buffers must be allocated, but the
  • frame data does not have to be ready at this point. Data
  • availability is then signalled by sws_send_slice().
  • @return 0 on success, a negative AVERROR code on failure *
  • @see sws_frame_end()

func SwsFreeContext 

func SwsFreeContext(swsContext *CSwsContext)

*

  • Free the swscaler context swsContext.
  • If swsContext is NULL, then does nothing.

func SwsFreeFilter 

func SwsFreeFilter(filter *CSwsFilter)

func SwsFreeVec 

func SwsFreeVec(a *CSwsVector)

func SwsGetClass 

func SwsGetClass() *avutil.CAVClass

*

  • Get the AVClass for swsContext. It can be used in combination with
  • AV_OPT_SEARCH_FAKE_OBJ for examining options. *
  • @see av_opt_find().

func SwsGetCoefficients 

func SwsGetCoefficients(colorspace int) unsafe.Pointer

*

  • Return a pointer to yuv<->rgb coefficients for the given colorspace
  • suitable for sws_setColorspaceDetails(). *
  • @param colorspace One of the SWS_CS_* macros. If invalid,
  • SWS_CS_DEFAULT is used.

func SwsGetColorspaceDetails 

func SwsGetColorspaceDetails(c *CSwsContext, invTable **ctypes.Int,
	srcRange *ctypes.Int, table **ctypes.Int, dstRange *ctypes.Int,
	brightness *ctypes.Int, contrast *ctypes.Int, saturation *ctypes.Int) int

*

  • @return A negative error code on error, non negative otherwise.
  • If `LIBSWSCALE_VERSION_MAJOR < 7`, returns -1 if not supported.

func SwsInitContext 

func SwsInitContext(sws_context *CSwsContext, srcFilter *CSwsFilter, dstFilter *CSwsFilter) int

*

  • Initialize the swscaler context sws_context. *
  • @return zero or positive value on success, a negative value on
  • error

func SwsIsSupportedEndiannessConversion 

func SwsIsSupportedEndiannessConversion(pixFmt avutil.CAVPixelFormat) int

*

  • @param[in] pix_fmt the pixel format
  • @return a positive value if an endianness conversion for pix_fmt is
  • supported, 0 otherwise.

func SwsIsSupportedInput 

func SwsIsSupportedInput(pixFmt avutil.CAVPixelFormat) int

*

  • Return a positive value if pix_fmt is a supported input format, 0
  • otherwise.

func SwsIsSupportedOutput 

func SwsIsSupportedOutput(pixFmt avutil.CAVPixelFormat) int

*

  • Return a positive value if pix_fmt is a supported output format, 0
  • otherwise.

func SwsNormalizeVec 

func SwsNormalizeVec(a *CSwsVector, height float64)

*

  • Scale all the coefficients of a so that their sum equals height.

func SwsReceiveSlice 

func SwsReceiveSlice(c *CSwsContext, sliceStart uint, sliceHeight uint) int

*

  • Request a horizontal slice of the output data to be written into the frame
  • previously provided to sws_frame_start(). *
  • @param c The scaling context
  • @param slice_start first row of the slice; must be a multiple of
  • sws_receive_slice_alignment()
  • @param slice_height number of rows in the slice; must be a multiple of
  • sws_receive_slice_alignment(), except for the last slice
  • (i.e. when slice_start+slice_height is equal to output
  • frame height) *
  • @return a non-negative number if the data was successfully written into the output
  • AVERROR(EAGAIN) if more input data needs to be provided before the
  • output can be produced
  • another negative AVERROR code on other kinds of scaling failure

func SwsReceiveSliceAlignment 

func SwsReceiveSliceAlignment(c *CSwsContext) uint

*

  • Get the alignment required for slices *
  • @param c The scaling context
  • @return alignment required for output slices requested with sws_receive_slice().
  • Slice offsets and sizes passed to sws_receive_slice() must be
  • multiples of the value returned from this function.

func SwsScale 

func SwsScale(c *CSwsContext, srcSlice []unsafe.Pointer, srcStride []ctypes.Int, srcSliceY int, srcSliceH int, dst []unsafe.Pointer, dstStride []ctypes.Int) int

*

  • Scale the image slice in srcSlice and put the resulting scaled
  • slice in the image in dst. A slice is a sequence of consecutive
  • rows in an image. *
  • Slices have to be provided in sequential order, either in
  • top-bottom or bottom-top order. If slices are provided in
  • non-sequential order the behavior of the function is undefined. *
  • @param c the scaling context previously created with
  • sws_getContext()
  • @param srcSlice the array containing the pointers to the planes of
  • the source slice
  • @param srcStride the array containing the strides for each plane of
  • the source image
  • @param srcSliceY the position in the source image of the slice to
  • process, that is the number (counted starting from
  • zero) in the image of the first row of the slice
  • @param srcSliceH the height of the source slice, that is the number
  • of rows in the slice
  • @param dst the array containing the pointers to the planes of
  • the destination image
  • @param dstStride the array containing the strides for each plane of
  • the destination image
  • @return the height of the output slice

func SwsScaleFrame 

func SwsScaleFrame(c *CSwsContext, dst *avutil.CAVFrame, src *avutil.CAVFrame) int

*

  • Scale source data from src and write the output to dst. *
  • This is merely a convenience wrapper around
  • - sws_frame_start()
  • - sws_send_slice(0, src->height)
  • - sws_receive_slice(0, dst->height)
  • - sws_frame_end() *
  • @param c The scaling context
  • @param dst The destination frame. See documentation for sws_frame_start() for
  • more details.
  • @param src The source frame. *
  • @return 0 on success, a negative AVERROR code on failure

func SwsScaleVec 

func SwsScaleVec(a *CSwsVector, scalar float64)

*

  • Scale all the coefficients of a by the scalar value.

func SwsSendSlice 

func SwsSendSlice(c *CSwsContext, sliceStart uint, sliceHeight uint) int

*

  • Indicate that a horizontal slice of input data is available in the source
  • frame previously provided to sws_frame_start(). The slices may be provided in
  • any order, but may not overlap. For vertically subsampled pixel formats, the
  • slices must be aligned according to subsampling. *
  • @param c The scaling context
  • @param slice_start first row of the slice
  • @param slice_height number of rows in the slice *
  • @return a non-negative number on success, a negative AVERROR code on failure.

func SwsSetColorspaceDetails 

func SwsSetColorspaceDetails(c *CSwsContext, invTable [4]int, srcRange int, table [4]int, dstRange int, brightness int, contrast int, saturation int) int

*

  • @param c the scaling context
  • @param dstRange flag indicating the while-black range of the output (1=jpeg / 0=mpeg)
  • @param srcRange flag indicating the while-black range of the input (1=jpeg / 0=mpeg)
  • @param table the yuv2rgb coefficients describing the output yuv space, normally ff_yuv2rgb_coeffs[x]
  • @param inv_table the yuv2rgb coefficients describing the input yuv space, normally ff_yuv2rgb_coeffs[x]
  • @param brightness 16.16 fixed point brightness correction
  • @param contrast 16.16 fixed point contrast correction
  • @param saturation 16.16 fixed point saturation correction *
  • @return A negative error code on error, non negative otherwise.
  • If `LIBSWSCALE_VERSION_MAJOR < 7`, returns -1 if not supported.

func SwscaleConfiguration 

func SwscaleConfiguration() string

*

  • Return the libswscale build-time configuration.

func SwscaleLicense 

func SwscaleLicense() string

*

  • Return the libswscale license.

func SwscaleVersion 

func SwscaleVersion() uint

*

  • @defgroup libsws libswscale
  • Color conversion and scaling library. *
  • @{ *
  • Return the LIBSWSCALE_VERSION_INT constant.

Types

type CSwsContext 

type CSwsContext C.struct_SwsContext

func SwsAllocContext 

func SwsAllocContext() *CSwsContext

*

  • Allocate an empty SwsContext. This must be filled and passed to
  • sws_init_context(). For filling see AVOptions, options.c and
  • sws_setColorspaceDetails().

func SwsGetCachedContext 

func SwsGetCachedContext(context *CSwsContext,
	srcW int, srcH int, srcFormat avutil.CAVPixelFormat,
	dstW int, dstH int, dstFormat avutil.CAVPixelFormat,
	flags int, srcFilter *CSwsFilter,
	dstFilter *CSwsFilter, param *float64) *CSwsContext

*

  • Check if context can be reused, otherwise reallocate a new one. *
  • If context is NULL, just calls sws_getContext() to get a new
  • context. Otherwise, checks if the parameters are the ones already
  • saved in context. If that is the case, returns the current
  • context. Otherwise, frees context and gets a new context with
  • the new parameters. *
  • Be warned that srcFilter and dstFilter are not checked, they
  • are assumed to remain the same.

func SwsGetContext 

func SwsGetContext(srcW int, srcH int, srcFormat avutil.CAVPixelFormat,
	dstW int, dstH int, dstFormat avutil.CAVPixelFormat,
	flags int, srcFilter *CSwsFilter,
	dstFilter *CSwsFilter, param *float64) *CSwsContext

*

  • Allocate and return an SwsContext. You need it to perform
  • scaling/conversion operations using sws_scale(). *
  • @param srcW the width of the source image
  • @param srcH the height of the source image
  • @param srcFormat the source image format
  • @param dstW the width of the destination image
  • @param dstH the height of the destination image
  • @param dstFormat the destination image format
  • @param flags specify which algorithm and options to use for rescaling
  • @param param extra parameters to tune the used scaler
  • For SWS_BICUBIC param[0] and [1] tune the shape of the basis
  • function, param[0] tunes f(1) and param[1] f´(1)
  • For SWS_GAUSS param[0] tunes the exponent and thus cutoff
  • frequency
  • For SWS_LANCZOS param[0] tunes the width of the window function
  • @return a pointer to an allocated context, or NULL in case of error
  • @note this function is to be removed after a saner alternative is
  • written

type CSwsFilter 

type CSwsFilter C.SwsFilter

vectors can be shared

func SwsGetDefaultFilter 

func SwsGetDefaultFilter(lumaGBlur float32, chromaGBlur float32,
	lumaSharpen float32, chromaSharpen float32,
	chromaHShift float32, chromaVShift float32,
	verbose int) *CSwsFilter

func (CSwsFilter) GetChrH 

func (sf CSwsFilter) GetChrH() *CSwsVector

func (CSwsFilter) GetChrV 

func (sf CSwsFilter) GetChrV() *CSwsVector

func (CSwsFilter) GetLumH 

func (sf CSwsFilter) GetLumH() *CSwsVector

func (CSwsFilter) GetLumV 

func (sf CSwsFilter) GetLumV() *CSwsVector

type CSwsVector 

type CSwsVector C.SwsVector

when used for filters they must have an odd number of elements coeffs cannot be shared between vectors

func SwsAllocVec 

func SwsAllocVec(length int) *CSwsVector

*

  • Allocate and return an uninitialized vector with length coefficients.

func SwsGetGaussianVec 

func SwsGetGaussianVec(variance float64, quality float64) *CSwsVector

*

  • Return a normalized Gaussian curve used to filter stuff
  • quality = 3 is high quality, lower is lower quality.

func (CSwsVector) GetCoeff 

func (sv CSwsVector) GetCoeff() *float64

/< pointer to the list of coefficients

func (CSwsVector) GetLength 

func (sv CSwsVector) GetLength() int

/< number of coefficients in the vector

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