1/*
2 * Copyright (C) 2001-2011 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#ifndef SWSCALE_SWSCALE_H
22#define SWSCALE_SWSCALE_H
23
24/**
25 * @file
26 * @ingroup libsws
27 * external API header
28 */
29
30#include <stdint.h>
31
32#include "libavutil/avutil.h"
33#include "libavutil/frame.h"
34#include "libavutil/log.h"
35#include "libavutil/pixfmt.h"
36#include "version_major.h"
37#ifndef HAVE_AV_CONFIG_H
38/* When included as part of the ffmpeg build, only include the major version
39 * to avoid unnecessary rebuilds. When included externally, keep including
40 * the full version information. */
41#include "version.h"
42#endif
43
44/**
45 * @defgroup libsws libswscale
46 * Color conversion and scaling library.
47 *
48 * @{
49 *
50 * Return the LIBSWSCALE_VERSION_INT constant.
51 */
52unsigned swscale_version(void);
53
54/**
55 * Return the libswscale build-time configuration.
56 */
57const char *swscale_configuration(void);
58
59/**
60 * Return the libswscale license.
61 */
62const char *swscale_license(void);
63
64/* values for the flags, the stuff on the command line is different */
65#define SWS_FAST_BILINEAR 1
66#define SWS_BILINEAR 2
67#define SWS_BICUBIC 4
68#define SWS_X 8
69#define SWS_POINT 0x10
70#define SWS_AREA 0x20
71#define SWS_BICUBLIN 0x40
72#define SWS_GAUSS 0x80
73#define SWS_SINC 0x100
74#define SWS_LANCZOS 0x200
75#define SWS_SPLINE 0x400
76
77#define SWS_SRC_V_CHR_DROP_MASK 0x30000
78#define SWS_SRC_V_CHR_DROP_SHIFT 16
79
80#define SWS_PARAM_DEFAULT 123456
81
82#define SWS_PRINT_INFO 0x1000
83
84//the following 3 flags are not completely implemented
85//internal chrominance subsampling info
86#define SWS_FULL_CHR_H_INT 0x2000
87//input subsampling info
88#define SWS_FULL_CHR_H_INP 0x4000
89#define SWS_DIRECT_BGR 0x8000
90#define SWS_ACCURATE_RND 0x40000
91#define SWS_BITEXACT 0x80000
92#define SWS_ERROR_DIFFUSION 0x800000
93
94#define SWS_MAX_REDUCE_CUTOFF 0.002
95
96#define SWS_CS_ITU709 1
97#define SWS_CS_FCC 4
98#define SWS_CS_ITU601 5
99#define SWS_CS_ITU624 5
100#define SWS_CS_SMPTE170M 5
101#define SWS_CS_SMPTE240M 7
102#define SWS_CS_DEFAULT 5
103#define SWS_CS_BT2020 9
104
105/**
106 * Return a pointer to yuv<->rgb coefficients for the given colorspace
107 * suitable for sws_setColorspaceDetails().
108 *
109 * @param colorspace One of the SWS_CS_* macros. If invalid,
110 * SWS_CS_DEFAULT is used.
111 */
112const int *sws_getCoefficients(int colorspace);
113
114// when used for filters they must have an odd number of elements
115// coeffs cannot be shared between vectors
116typedef struct SwsVector {
117 double *coeff; ///< pointer to the list of coefficients
118 int length; ///< number of coefficients in the vector
119} SwsVector;
120
121// vectors can be shared
122typedef struct SwsFilter {
123 SwsVector *lumH;
124 SwsVector *lumV;
125 SwsVector *chrH;
126 SwsVector *chrV;
127} SwsFilter;
128
129struct SwsContext;
130
131/**
132 * Return a positive value if pix_fmt is a supported input format, 0
133 * otherwise.
134 */
135int sws_isSupportedInput(enum AVPixelFormat pix_fmt);
136
137/**
138 * Return a positive value if pix_fmt is a supported output format, 0
139 * otherwise.
140 */
141int sws_isSupportedOutput(enum AVPixelFormat pix_fmt);
142
143/**
144 * @param[in] pix_fmt the pixel format
145 * @return a positive value if an endianness conversion for pix_fmt is
146 * supported, 0 otherwise.
147 */
148int sws_isSupportedEndiannessConversion(enum AVPixelFormat pix_fmt);
149
150/**
151 * Allocate an empty SwsContext. This must be filled and passed to
152 * sws_init_context(). For filling see AVOptions, options.c and
153 * sws_setColorspaceDetails().
154 */
155struct SwsContext *sws_alloc_context(void);
156
157/**
158 * Initialize the swscaler context sws_context.
159 *
160 * @return zero or positive value on success, a negative value on
161 * error
162 */
163av_warn_unused_result
164int sws_init_context(struct SwsContext *sws_context, SwsFilter *srcFilter, SwsFilter *dstFilter);
165
166/**
167 * Free the swscaler context swsContext.
168 * If swsContext is NULL, then does nothing.
169 */
170void sws_freeContext(struct SwsContext *swsContext);
171
172/**
173 * Allocate and return an SwsContext. You need it to perform
174 * scaling/conversion operations using sws_scale().
175 *
176 * @param srcW the width of the source image
177 * @param srcH the height of the source image
178 * @param srcFormat the source image format
179 * @param dstW the width of the destination image
180 * @param dstH the height of the destination image
181 * @param dstFormat the destination image format
182 * @param flags specify which algorithm and options to use for rescaling
183 * @param param extra parameters to tune the used scaler
184 * For SWS_BICUBIC param[0] and [1] tune the shape of the basis
185 * function, param[0] tunes f(1) and param[1] f´(1)
186 * For SWS_GAUSS param[0] tunes the exponent and thus cutoff
187 * frequency
188 * For SWS_LANCZOS param[0] tunes the width of the window function
189 * @return a pointer to an allocated context, or NULL in case of error
190 * @note this function is to be removed after a saner alternative is
191 * written
192 */
193struct SwsContext *sws_getContext(int srcW, int srcH, enum AVPixelFormat srcFormat,
194 int dstW, int dstH, enum AVPixelFormat dstFormat,
195 int flags, SwsFilter *srcFilter,
196 SwsFilter *dstFilter, const double *param);
197
198/**
199 * Scale the image slice in srcSlice and put the resulting scaled
200 * slice in the image in dst. A slice is a sequence of consecutive
201 * rows in an image.
202 *
203 * Slices have to be provided in sequential order, either in
204 * top-bottom or bottom-top order. If slices are provided in
205 * non-sequential order the behavior of the function is undefined.
206 *
207 * @param c the scaling context previously created with
208 * sws_getContext()
209 * @param srcSlice the array containing the pointers to the planes of
210 * the source slice
211 * @param srcStride the array containing the strides for each plane of
212 * the source image
213 * @param srcSliceY the position in the source image of the slice to
214 * process, that is the number (counted starting from
215 * zero) in the image of the first row of the slice
216 * @param srcSliceH the height of the source slice, that is the number
217 * of rows in the slice
218 * @param dst the array containing the pointers to the planes of
219 * the destination image
220 * @param dstStride the array containing the strides for each plane of
221 * the destination image
222 * @return the height of the output slice
223 */
224int sws_scale(struct SwsContext *c, const uint8_t *const srcSlice[],
225 const int srcStride[], int srcSliceY, int srcSliceH,
226 uint8_t *const dst[], const int dstStride[]);
227
228/**
229 * Scale source data from src and write the output to dst.
230 *
231 * This is merely a convenience wrapper around
232 * - sws_frame_start()
233 * - sws_send_slice(0, src->height)
234 * - sws_receive_slice(0, dst->height)
235 * - sws_frame_end()
236 *
237 * @param c The scaling context
238 * @param dst The destination frame. See documentation for sws_frame_start() for
239 * more details.
240 * @param src The source frame.
241 *
242 * @return 0 on success, a negative AVERROR code on failure
243 */
244int sws_scale_frame(struct SwsContext *c, AVFrame *dst, const AVFrame *src);
245
246/**
247 * Initialize the scaling process for a given pair of source/destination frames.
248 * Must be called before any calls to sws_send_slice() and sws_receive_slice().
249 *
250 * This function will retain references to src and dst, so they must both use
251 * refcounted buffers (if allocated by the caller, in case of dst).
252 *
253 * @param c The scaling context
254 * @param dst The destination frame.
255 *
256 * The data buffers may either be already allocated by the caller or
257 * left clear, in which case they will be allocated by the scaler.
258 * The latter may have performance advantages - e.g. in certain cases
259 * some output planes may be references to input planes, rather than
260 * copies.
261 *
262 * Output data will be written into this frame in successful
263 * sws_receive_slice() calls.
264 * @param src The source frame. The data buffers must be allocated, but the
265 * frame data does not have to be ready at this point. Data
266 * availability is then signalled by sws_send_slice().
267 * @return 0 on success, a negative AVERROR code on failure
268 *
269 * @see sws_frame_end()
270 */
271int sws_frame_start(struct SwsContext *c, AVFrame *dst, const AVFrame *src);
272
273/**
274 * Finish the scaling process for a pair of source/destination frames previously
275 * submitted with sws_frame_start(). Must be called after all sws_send_slice()
276 * and sws_receive_slice() calls are done, before any new sws_frame_start()
277 * calls.
278 *
279 * @param c The scaling context
280 */
281void sws_frame_end(struct SwsContext *c);
282
283/**
284 * Indicate that a horizontal slice of input data is available in the source
285 * frame previously provided to sws_frame_start(). The slices may be provided in
286 * any order, but may not overlap. For vertically subsampled pixel formats, the
287 * slices must be aligned according to subsampling.
288 *
289 * @param c The scaling context
290 * @param slice_start first row of the slice
291 * @param slice_height number of rows in the slice
292 *
293 * @return a non-negative number on success, a negative AVERROR code on failure.
294 */
295int sws_send_slice(struct SwsContext *c, unsigned int slice_start,
296 unsigned int slice_height);
297
298/**
299 * Request a horizontal slice of the output data to be written into the frame
300 * previously provided to sws_frame_start().
301 *
302 * @param c The scaling context
303 * @param slice_start first row of the slice; must be a multiple of
304 * sws_receive_slice_alignment()
305 * @param slice_height number of rows in the slice; must be a multiple of
306 * sws_receive_slice_alignment(), except for the last slice
307 * (i.e. when slice_start+slice_height is equal to output
308 * frame height)
309 *
310 * @return a non-negative number if the data was successfully written into the output
311 * AVERROR(EAGAIN) if more input data needs to be provided before the
312 * output can be produced
313 * another negative AVERROR code on other kinds of scaling failure
314 */
315int sws_receive_slice(struct SwsContext *c, unsigned int slice_start,
316 unsigned int slice_height);
317
318/**
319 * Get the alignment required for slices
320 *
321 * @param c The scaling context
322 * @return alignment required for output slices requested with sws_receive_slice().
323 * Slice offsets and sizes passed to sws_receive_slice() must be
324 * multiples of the value returned from this function.
325 */
326unsigned int sws_receive_slice_alignment(const struct SwsContext *c);
327
328/**
329 * @param c the scaling context
330 * @param dstRange flag indicating the while-black range of the output (1=jpeg / 0=mpeg)
331 * @param srcRange flag indicating the while-black range of the input (1=jpeg / 0=mpeg)
332 * @param table the yuv2rgb coefficients describing the output yuv space, normally ff_yuv2rgb_coeffs[x]
333 * @param inv_table the yuv2rgb coefficients describing the input yuv space, normally ff_yuv2rgb_coeffs[x]
334 * @param brightness 16.16 fixed point brightness correction
335 * @param contrast 16.16 fixed point contrast correction
336 * @param saturation 16.16 fixed point saturation correction
337 *
338 * @return A negative error code on error, non negative otherwise.
339 * If `LIBSWSCALE_VERSION_MAJOR < 7`, returns -1 if not supported.
340 */
341int sws_setColorspaceDetails(struct SwsContext *c, const int inv_table[4],
342 int srcRange, const int table[4], int dstRange,
343 int brightness, int contrast, int saturation);
344
345/**
346 * @return A negative error code on error, non negative otherwise.
347 * If `LIBSWSCALE_VERSION_MAJOR < 7`, returns -1 if not supported.
348 */
349int sws_getColorspaceDetails(struct SwsContext *c, int **inv_table,
350 int *srcRange, int **table, int *dstRange,
351 int *brightness, int *contrast, int *saturation);
352
353/**
354 * Allocate and return an uninitialized vector with length coefficients.
355 */
356SwsVector *sws_allocVec(int length);
357
358/**
359 * Return a normalized Gaussian curve used to filter stuff
360 * quality = 3 is high quality, lower is lower quality.
361 */
362SwsVector *sws_getGaussianVec(double variance, double quality);
363
364/**
365 * Scale all the coefficients of a by the scalar value.
366 */
367void sws_scaleVec(SwsVector *a, double scalar);
368
369/**
370 * Scale all the coefficients of a so that their sum equals height.
371 */
372void sws_normalizeVec(SwsVector *a, double height);
373
374void sws_freeVec(SwsVector *a);
375
376SwsFilter *sws_getDefaultFilter(float lumaGBlur, float chromaGBlur,
377 float lumaSharpen, float chromaSharpen,
378 float chromaHShift, float chromaVShift,
379 int verbose);
380void sws_freeFilter(SwsFilter *filter);
381
382/**
383 * Check if context can be reused, otherwise reallocate a new one.
384 *
385 * If context is NULL, just calls sws_getContext() to get a new
386 * context. Otherwise, checks if the parameters are the ones already
387 * saved in context. If that is the case, returns the current
388 * context. Otherwise, frees context and gets a new context with
389 * the new parameters.
390 *
391 * Be warned that srcFilter and dstFilter are not checked, they
392 * are assumed to remain the same.
393 */
394struct SwsContext *sws_getCachedContext(struct SwsContext *context,
395 int srcW, int srcH, enum AVPixelFormat srcFormat,
396 int dstW, int dstH, enum AVPixelFormat dstFormat,
397 int flags, SwsFilter *srcFilter,
398 SwsFilter *dstFilter, const double *param);
399
400/**
401 * Convert an 8-bit paletted frame into a frame with a color depth of 32 bits.
402 *
403 * The output frame will have the same packed format as the palette.
404 *
405 * @param src source frame buffer
406 * @param dst destination frame buffer
407 * @param num_pixels number of pixels to convert
408 * @param palette array with [256] entries, which must match color arrangement (RGB or BGR) of src
409 */
410void sws_convertPalette8ToPacked32(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
411
412/**
413 * Convert an 8-bit paletted frame into a frame with a color depth of 24 bits.
414 *
415 * With the palette format "ABCD", the destination frame ends up with the format "ABC".
416 *
417 * @param src source frame buffer
418 * @param dst destination frame buffer
419 * @param num_pixels number of pixels to convert
420 * @param palette array with [256] entries, which must match color arrangement (RGB or BGR) of src
421 */
422void sws_convertPalette8ToPacked24(const uint8_t *src, uint8_t *dst, int num_pixels, const uint8_t *palette);
423
424/**
425 * Get the AVClass for swsContext. It can be used in combination with
426 * AV_OPT_SEARCH_FAKE_OBJ for examining options.
427 *
428 * @see av_opt_find().
429 */
430const AVClass *sws_get_class(void);
431
432/**
433 * @}
434 */
435
436#endif /* SWSCALE_SWSCALE_H */
437

source code of include/x86_64-linux-gnu/libswscale/swscale.h