imgutils: Document av_image_get_buffer_size()
[libav.git] / libavutil / imgutils.h
1 /*
2 * This file is part of Libav.
3 *
4 * Libav is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * Libav is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with Libav; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 #ifndef AVUTIL_IMGUTILS_H
20 #define AVUTIL_IMGUTILS_H
21
22 /**
23 * @file
24 * misc image utilities
25 *
26 * @addtogroup lavu_picture
27 * @{
28 */
29
30 #include "avutil.h"
31 #include "pixdesc.h"
32 #include "rational.h"
33
34 /**
35 * Compute the max pixel step for each plane of an image with a
36 * format described by pixdesc.
37 *
38 * The pixel step is the distance in bytes between the first byte of
39 * the group of bytes which describe a pixel component and the first
40 * byte of the successive group in the same plane for the same
41 * component.
42 *
43 * @param max_pixsteps an array which is filled with the max pixel step
44 * for each plane. Since a plane may contain different pixel
45 * components, the computed max_pixsteps[plane] is relative to the
46 * component in the plane with the max pixel step.
47 * @param max_pixstep_comps an array which is filled with the component
48 * for each plane which has the max pixel step. May be NULL.
49 */
50 void av_image_fill_max_pixsteps(int max_pixsteps[4], int max_pixstep_comps[4],
51 const AVPixFmtDescriptor *pixdesc);
52
53 /**
54 * Compute the size of an image line with format pix_fmt and width
55 * width for the plane plane.
56 *
57 * @return the computed size in bytes
58 */
59 int av_image_get_linesize(enum AVPixelFormat pix_fmt, int width, int plane);
60
61 /**
62 * Fill plane linesizes for an image with pixel format pix_fmt and
63 * width width.
64 *
65 * @param linesizes array to be filled with the linesize for each plane
66 * @return >= 0 in case of success, a negative error code otherwise
67 */
68 int av_image_fill_linesizes(int linesizes[4], enum AVPixelFormat pix_fmt, int width);
69
70 /**
71 * Fill plane data pointers for an image with pixel format pix_fmt and
72 * height height.
73 *
74 * @param data pointers array to be filled with the pointer for each image plane
75 * @param ptr the pointer to a buffer which will contain the image
76 * @param linesizes the array containing the linesize for each
77 * plane, should be filled by av_image_fill_linesizes()
78 * @return the size in bytes required for the image buffer, a negative
79 * error code in case of failure
80 */
81 int av_image_fill_pointers(uint8_t *data[4], enum AVPixelFormat pix_fmt, int height,
82 uint8_t *ptr, const int linesizes[4]);
83
84 /**
85 * Allocate an image with size w and h and pixel format pix_fmt, and
86 * fill pointers and linesizes accordingly.
87 * The allocated image buffer has to be freed by using
88 * av_freep(&pointers[0]).
89 *
90 * @param align the value to use for buffer size alignment
91 * @return the size in bytes required for the image buffer, a negative
92 * error code in case of failure
93 */
94 int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
95 int w, int h, enum AVPixelFormat pix_fmt, int align);
96
97 /**
98 * Copy image plane from src to dst.
99 * That is, copy "height" number of lines of "bytewidth" bytes each.
100 * The first byte of each successive line is separated by *_linesize
101 * bytes.
102 *
103 * @param dst_linesize linesize for the image plane in dst
104 * @param src_linesize linesize for the image plane in src
105 */
106 void av_image_copy_plane(uint8_t *dst, int dst_linesize,
107 const uint8_t *src, int src_linesize,
108 int bytewidth, int height);
109
110 /**
111 * Copy image in src_data to dst_data.
112 *
113 * @param dst_linesizes linesizes for the image in dst_data
114 * @param src_linesizes linesizes for the image in src_data
115 */
116 void av_image_copy(uint8_t *dst_data[4], int dst_linesizes[4],
117 const uint8_t *src_data[4], const int src_linesizes[4],
118 enum AVPixelFormat pix_fmt, int width, int height);
119
120 /**
121 * Copy image data located in uncacheable (e.g. GPU mapped) memory. Where
122 * available, this function will use special functionality for reading from such
123 * memory, which may result in greatly improved performance compared to plain
124 * av_image_copy().
125 *
126 * The data pointers and the linesizes must be aligned to the maximum required
127 * by the CPU architecture.
128 *
129 * @note The linesize parameters have the type ptrdiff_t here, while they are
130 * int for av_image_copy().
131 * @note On x86, the linesizes currently need to be aligned to the cacheline
132 * size (i.e. 64) to get improved performance.
133 */
134 void av_image_copy_uc_from(uint8_t *dst_data[4], const ptrdiff_t dst_linesizes[4],
135 const uint8_t *src_data[4], const ptrdiff_t src_linesizes[4],
136 enum AVPixelFormat pix_fmt, int width, int height);
137
138 /**
139 * Setup the data pointers and linesizes based on the specified image
140 * parameters and the provided array.
141 *
142 * The fields of the given image are filled in by using the src
143 * address which points to the image data buffer. Depending on the
144 * specified pixel format, one or multiple image data pointers and
145 * line sizes will be set. If a planar format is specified, several
146 * pointers will be set pointing to the different picture planes and
147 * the line sizes of the different planes will be stored in the
148 * lines_sizes array. Call with src == NULL to get the required
149 * size for the src buffer.
150 *
151 * To allocate the buffer and fill in the dst_data and dst_linesize in
152 * one call, use av_image_alloc().
153 *
154 * @param dst_data data pointers to be filled in
155 * @param dst_linesize linesizes for the image in dst_data to be filled in
156 * @param src buffer which will contain or contains the actual image data, can be NULL
157 * @param pix_fmt the pixel format of the image
158 * @param width the width of the image in pixels
159 * @param height the height of the image in pixels
160 * @param align the value used in src for linesize alignment
161 * @return the size in bytes required for src, a negative error code
162 * in case of failure
163 */
164 int av_image_fill_arrays(uint8_t *dst_data[4], int dst_linesize[4],
165 const uint8_t *src,
166 enum AVPixelFormat pix_fmt, int width, int height, int align);
167
168 /**
169 * Return the size in bytes of the amount of data required to store an
170 * image with the given parameters.
171 *
172 * @param pix_fmt the pixel format of the image
173 * @param width the width of the image in pixels
174 * @param height the height of the image in pixels
175 * @param align the assumed linesize alignment
176 * @return the buffer size in bytes, a negative error code in case of failure
177 */
178 int av_image_get_buffer_size(enum AVPixelFormat pix_fmt, int width, int height, int align);
179
180 /**
181 * Copy image data from an image into a buffer.
182 *
183 * av_image_get_buffer_size() can be used to compute the required size
184 * for the buffer to fill.
185 *
186 * @param dst a buffer into which picture data will be copied
187 * @param dst_size the size in bytes of dst
188 * @param src_data pointers containing the source image data
189 * @param src_linesize linesizes for the image in src_data
190 * @param pix_fmt the pixel format of the source image
191 * @param width the width of the source image in pixels
192 * @param height the height of the source image in pixels
193 * @param align the assumed linesize alignment for dst
194 * @return the number of bytes written to dst, or a negative value
195 * (error code) on error
196 */
197 int av_image_copy_to_buffer(uint8_t *dst, int dst_size,
198 const uint8_t * const src_data[4], const int src_linesize[4],
199 enum AVPixelFormat pix_fmt, int width, int height, int align);
200
201 /**
202 * Check if the given dimension of an image is valid, meaning that all
203 * bytes of the image can be addressed with a signed int.
204 *
205 * @param w the width of the picture
206 * @param h the height of the picture
207 * @param log_offset the offset to sum to the log level for logging with log_ctx
208 * @param log_ctx the parent logging context, it may be NULL
209 * @return >= 0 if valid, a negative error code otherwise
210 */
211 int av_image_check_size(unsigned int w, unsigned int h, int log_offset, void *log_ctx);
212
213 /**
214 * Check if the given sample aspect ratio of an image is valid.
215 *
216 * It is considered invalid if the denominator is 0 or if applying the ratio
217 * to the image size would make the smaller dimension less than 1. If the
218 * sar numerator is 0, it is considered unknown and will return as valid.
219 *
220 * @param w width of the image
221 * @param h height of the image
222 * @param sar sample aspect ratio of the image
223 * @return 0 if valid, a negative AVERROR code otherwise
224 */
225 int av_image_check_sar(unsigned int w, unsigned int h, AVRational sar);
226
227 /**
228 * @}
229 */
230
231
232 #endif /* AVUTIL_IMGUTILS_H */