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FFmpeg/libswscale/swscale.h

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/*
* Copyright (C) 2024 Niklas Haas
* Copyright (C) 2001-2011 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef SWSCALE_SWSCALE_H
#define SWSCALE_SWSCALE_H
/**
* @file
* @ingroup libsws
* external API header
*/
#include <stdint.h>
#include "libavutil/avutil.h"
#include "libavutil/frame.h"
#include "libavutil/log.h"
#include "libavutil/pixfmt.h"
#include "version_major.h"
#ifndef HAVE_AV_CONFIG_H
/* When included as part of the ffmpeg build, only include the major version
* to avoid unnecessary rebuilds. When included externally, keep including
* the full version information. */
#include "version.h"
#endif
/**
* @defgroup libsws libswscale
* Color conversion and scaling library.
*
* @{
*
* Return the LIBSWSCALE_VERSION_INT constant.
*/
unsigned swscale_version(void);
/**
* Return the libswscale build-time configuration.
*/
const char *swscale_configuration(void);
/**
* Return the libswscale license.
*/
const char *swscale_license(void);
/**
* Get the AVClass for SwsContext. It can be used in combination with
* AV_OPT_SEARCH_FAKE_OBJ for examining options.
*
* @see av_opt_find().
*/
const AVClass *sws_get_class(void);
/******************************
* Flags and quality settings *
******************************/
typedef enum SwsDither {
SWS_DITHER_NONE = 0, /* disable dithering */
SWS_DITHER_AUTO, /* auto-select from preset */
SWS_DITHER_BAYER, /* ordered dither matrix */
SWS_DITHER_ED, /* error diffusion */
SWS_DITHER_A_DITHER, /* arithmetic addition */
SWS_DITHER_X_DITHER, /* arithmetic xor */
SWS_DITHER_NB, /* not part of the ABI */
} SwsDither;
typedef enum SwsAlphaBlend {
SWS_ALPHA_BLEND_NONE = 0,
SWS_ALPHA_BLEND_UNIFORM,
SWS_ALPHA_BLEND_CHECKERBOARD,
SWS_ALPHA_BLEND_NB, /* not part of the ABI */
} SwsAlphaBlend;
typedef enum SwsFlags {
/**
* Scaler selection options. Only one may be active at a time.
*/
SWS_FAST_BILINEAR = 1 << 0, ///< fast bilinear filtering
SWS_BILINEAR = 1 << 1, ///< bilinear filtering
SWS_BICUBIC = 1 << 2, ///< 2-tap cubic B-spline
SWS_X = 1 << 3, ///< experimental
SWS_POINT = 1 << 4, ///< nearest neighbor
SWS_AREA = 1 << 5, ///< area averaging
SWS_BICUBLIN = 1 << 6, ///< bicubic luma, bilinear chroma
SWS_GAUSS = 1 << 7, ///< gaussian approximation
SWS_SINC = 1 << 8, ///< unwindowed sinc
SWS_LANCZOS = 1 << 9, ///< 3-tap sinc/sinc
SWS_SPLINE = 1 << 10, ///< cubic Keys spline
/**
* Return an error on underspecified conversions. Without this flag,
* unspecified fields are defaulted to sensible values.
*/
SWS_STRICT = 1 << 11,
/**
* Emit verbose log of scaling parameters.
*/
SWS_PRINT_INFO = 1 << 12,
/**
* Perform full chroma upsampling when upscaling to RGB.
*
* For example, when converting 50x50 yuv420p to 100x100 rgba, setting this flag
* will scale the chroma plane from 25x25 to 100x100 (4:4:4), and then convert
* the 100x100 yuv444p image to rgba in the final output step.
*
* Without this flag, the chroma plane is instead scaled to 50x100 (4:2:2),
* with a single chroma sample being re-used for both of the horizontally
* adjacent RGBA output pixels.
*/
SWS_FULL_CHR_H_INT = 1 << 13,
/**
* Perform full chroma interpolation when downscaling RGB sources.
*
* For example, when converting a 100x100 rgba source to 50x50 yuv444p, setting
* this flag will generate a 100x100 (4:4:4) chroma plane, which is then
* downscaled to the required 50x50.
*
* Without this flag, the chroma plane is instead generated at 50x100 (dropping
* every other pixel), before then being downscaled to the required 50x50
* resolution.
*/
SWS_FULL_CHR_H_INP = 1 << 14,
/**
* Force bit-exact output. This will prevent the use of platform-specific
* optimizations that may lead to slight difference in rounding, in favor
* of always maintaining exact bit output compatibility with the reference
* C code.
*
* Note: It is recommended to set both of these flags simultaneously.
*/
SWS_ACCURATE_RND = 1 << 18,
SWS_BITEXACT = 1 << 19,
/**
* Deprecated flags.
*/
SWS_DIRECT_BGR = 1 << 15, ///< This flag has no effect
SWS_ERROR_DIFFUSION = 1 << 23, ///< Set `SwsContext.dither` instead
} SwsFlags;
/***********************************
* Context creation and management *
***********************************/
/**
* Main external API structure. New fields can be added to the end with
* minor version bumps. Removal, reordering and changes to existing fields
* require a major version bump. sizeof(SwsContext) is not part of the ABI.
*/
typedef struct SwsContext {
const AVClass *av_class;
/**
* Private data of the user, can be used to carry app specific stuff.
*/
void *opaque;
/**
* Bitmask of SWS_*. See `SwsFlags` for details.
*/
unsigned flags;
/**
* Extra parameters for fine-tuning certain scalers.
*/
double scaler_params[2];
/**
* How many threads to use for processing, or 0 for automatic selection.
*/
int threads;
/**
* Dither mode.
*/
SwsDither dither;
/**
* Alpha blending mode. See `SwsAlphaBlend` for details.
*/
SwsAlphaBlend alpha_blend;
/**
* Use gamma correct scaling.
*/
int gamma_flag;
/**
* Deprecated frame property overrides, for the legacy API only.
*
* Ignored by sws_scale_frame() when used in dynamic mode, in which
* case all properties are instead taken from the frame directly.
*/
int src_w, src_h; ///< Width and height of the source frame
int dst_w, dst_h; ///< Width and height of the destination frame
int src_format; ///< Source pixel format
int dst_format; ///< Destination pixel format
int src_range; ///< Source is full range
int dst_range; ///< Destination is full range
int src_v_chr_pos; ///< Source vertical chroma position in luma grid / 256
int src_h_chr_pos; ///< Source horizontal chroma position
int dst_v_chr_pos; ///< Destination vertical chroma position
int dst_h_chr_pos; ///< Destination horizontal chroma position
/* Remember to add new fields to graph.c:opts_equal() */
} SwsContext;
/**
* Allocate an empty SwsContext and set its fields to default values.
*/
SwsContext *sws_alloc_context(void);
/**
* Free the context and everything associated with it, and write NULL
* to the provided pointer.
*/
void sws_free_context(SwsContext **ctx);
/***************************
* Supported frame formats *
***************************/
/**
* Test if a given pixel format is supported.
*
* @param output If 0, test if compatible with the source/input frame;
* otherwise, with the destination/output frame.
* @param format The format to check.
*
* @return A positive integer if supported, 0 otherwise.
*/
int sws_test_format(enum AVPixelFormat format, int output);
/**
* Test if a given color space is supported.
*
* @param output If 0, test if compatible with the source/input frame;
* otherwise, with the destination/output frame.
* @param colorspace The colorspace to check.
*
* @return A positive integer if supported, 0 otherwise.
*/
int sws_test_colorspace(enum AVColorSpace colorspace, int output);
/**
* Test if a given set of color primaries is supported.
*
* @param output If 0, test if compatible with the source/input frame;
* otherwise, with the destination/output frame.
* @param primaries The color primaries to check.
*
* @return A positive integer if supported, 0 otherwise.
*/
int sws_test_primaries(enum AVColorPrimaries primaries, int output);
/**
* Test if a given color transfer function is supported.
*
* @param output If 0, test if compatible with the source/input frame;
* otherwise, with the destination/output frame.
* @param trc The color transfer function to check.
*
* @return A positive integer if supported, 0 otherwise.
*/
int sws_test_transfer(enum AVColorTransferCharacteristic trc, int output);
/**
* Helper function to run all sws_test_* against a frame, as well as testing
* the basic frame properties for sanity. Ignores irrelevant properties - for
* example, AVColorSpace is not checked for RGB frames.
*/
int sws_test_frame(const AVFrame *frame, int output);
/**
* Like `sws_scale_frame`, but without actually scaling. It will instead
* merely initialize internal state that *would* be required to perform the
* operation, as well as returning the correct error code for unsupported
* frame combinations.
*
* @param ctx The scaling context.
* @param dst The destination frame to consider.
* @param src The source frame to consider.
* @return 0 on success, a negative AVERROR code on failure.
*/
int sws_frame_setup(SwsContext *ctx, const AVFrame *dst, const AVFrame *src);
/********************
* Main scaling API *
********************/
/**
* Check if a given conversion is a noop. Returns a positive integer if
* no operation needs to be performed, 0 otherwise.
*/
int sws_is_noop(const AVFrame *dst, const AVFrame *src);
/**
* Scale source data from `src` and write the output to `dst`.
*
* This function can be used directly on an allocated context, without setting
* up any frame properties or calling `sws_init_context()`. Such usage is fully
* dynamic and does not require reallocation if the frame properties change.
*
* Alternatively, this function can be called on a context that has been
* explicitly initialized. However, this is provided only for backwards
* compatibility. In this usage mode, all frame properties must be correctly
* set at init time, and may no longer change after initialization.
*
* @param ctx 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 (or all) output planes
* may be references to input planes, rather than copies.
* @param src The source frame. If the data buffers are set to NULL, then
* this function behaves identically to `sws_frame_setup`.
* @return 0 on success, a negative AVERROR code on failure.
*/
int sws_scale_frame(SwsContext *c, AVFrame *dst, const AVFrame *src);
/*************************
* Legacy (stateful) API *
*************************/
#define SWS_SRC_V_CHR_DROP_MASK 0x30000
#define SWS_SRC_V_CHR_DROP_SHIFT 16
#define SWS_PARAM_DEFAULT 123456
#define SWS_MAX_REDUCE_CUTOFF 0.002
#define SWS_CS_ITU709 1
#define SWS_CS_FCC 4
#define SWS_CS_ITU601 5
#define SWS_CS_ITU624 5
#define SWS_CS_SMPTE170M 5
#define SWS_CS_SMPTE240M 7
#define SWS_CS_DEFAULT 5
#define SWS_CS_BT2020 9
/**
* 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.
*/
const int *sws_getCoefficients(int colorspace);
// when used for filters they must have an odd number of elements
// coeffs cannot be shared between vectors
typedef struct SwsVector {
double *coeff; ///< pointer to the list of coefficients
int length; ///< number of coefficients in the vector
} SwsVector;
// vectors can be shared
typedef struct SwsFilter {
SwsVector *lumH;
SwsVector *lumV;
SwsVector *chrH;
SwsVector *chrV;
} SwsFilter;
/**
* Return a positive value if pix_fmt is a supported input format, 0
* otherwise.
*/
int sws_isSupportedInput(enum AVPixelFormat pix_fmt);
/**
* Return a positive value if pix_fmt is a supported output format, 0
* otherwise.
*/
int sws_isSupportedOutput(enum AVPixelFormat pix_fmt);
/**
* @param[in] pix_fmt the pixel format
* @return a positive value if an endianness conversion for pix_fmt is
* supported, 0 otherwise.
*/
int sws_isSupportedEndiannessConversion(enum AVPixelFormat pix_fmt);
/**
* Initialize the swscaler context sws_context.
*
* This function is considered deprecated, and provided only for backwards
* compatibility with sws_scale() and sws_start_frame(). The preferred way to
* use libswscale is to set all frame properties correctly and call
* sws_scale_frame() directly, without explicitly initializing the context.
*
* @return zero or positive value on success, a negative value on
* error
*/
av_warn_unused_result
int sws_init_context(SwsContext *sws_context, SwsFilter *srcFilter, SwsFilter *dstFilter);
/**
* Free the swscaler context swsContext.
* If swsContext is NULL, then does nothing.
*/
void sws_freeContext(SwsContext *swsContext);
/**
* 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
*/
SwsContext *sws_getContext(int srcW, int srcH, enum AVPixelFormat srcFormat,
int dstW, int dstH, enum AVPixelFormat dstFormat,
int flags, SwsFilter *srcFilter,
SwsFilter *dstFilter, const double *param);
/**
* 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. Requires a context that has been previously
* been initialized with sws_init_context().
*
* 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
*/
int sws_scale(SwsContext *c, const uint8_t *const srcSlice[],
const int srcStride[], int srcSliceY, int srcSliceH,
uint8_t *const dst[], const int dstStride[]);
/**
* 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().
* Requires a context that has been previously been initialized with
* sws_init_context().
*
* 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()
*/
int sws_frame_start(SwsContext *c, AVFrame *dst, const AVFrame *src);
/**
* 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
*/
void sws_frame_end(SwsContext *c);
/**
* 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.
*/
int sws_send_slice(SwsContext *c, unsigned int slice_start,
unsigned int slice_height);
/**
* 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
*/
int sws_receive_slice(SwsContext *c, unsigned int slice_start,
unsigned int slice_height);
/**
* Get the alignment required for slices. Requires a context that has been
* previously been initialized with sws_init_context().
*
* @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.
*/
unsigned int sws_receive_slice_alignment(const SwsContext *c);
/**
* @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.
*/
int sws_setColorspaceDetails(SwsContext *c, const int inv_table[4],
int srcRange, const int table[4], int dstRange,
int brightness, int contrast, int saturation);
/**
* @return A negative error code on error, non negative otherwise.
* If `LIBSWSCALE_VERSION_MAJOR < 7`, returns -1 if not supported.
*/
int sws_getColorspaceDetails(SwsContext *c, int **inv_table,
int *srcRange, int **table, int *dstRange,
int *brightness, int *contrast, int *saturation);
/**
* Allocate and return an uninitialized vector with length coefficients.
*/
SwsVector *sws_allocVec(int length);
/**
* Return a normalized Gaussian curve used to filter stuff
* quality = 3 is high quality, lower is lower quality.
*/
SwsVector *sws_getGaussianVec(double variance, double quality);
/**
* Scale all the coefficients of a by the scalar value.
*/
void sws_scaleVec(SwsVector *a, double scalar);
/**
* Scale all the coefficients of a so that their sum equals height.
*/
void sws_normalizeVec(SwsVector *a, double height);
void sws_freeVec(SwsVector *a);
SwsFilter *sws_getDefaultFilter(float lumaGBlur, float chromaGBlur,
float lumaSharpen, float chromaSharpen,
float chromaHShift, float chromaVShift,
int verbose);
void sws_freeFilter(SwsFilter *filter);
/**
* 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.
*/
SwsContext *sws_getCachedContext(SwsContext *context, int srcW, int srcH,
enum AVPixelFormat srcFormat, int dstW, int dstH,
enum AVPixelFormat dstFormat, int flags,
SwsFilter *srcFilter, SwsFilter *dstFilter,
const double *param);
/**
* 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
*/
void sws_convertPalette8ToPacked32(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
/**
* 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
*/
void sws_convertPalette8ToPacked24(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
/**
* @}
*/
#endif /* SWSCALE_SWSCALE_H */