1/*
2 * pixel format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#ifndef AVUTIL_PIXDESC_H
23#define AVUTIL_PIXDESC_H
24
25#include <inttypes.h>
26
27#include "attributes.h"
28#include "pixfmt.h"
29
30typedef struct AVComponentDescriptor{
31    uint16_t plane        :2;            ///< which of the 4 planes contains the component
32
33    /**
34     * Number of elements between 2 horizontally consecutive pixels minus 1.
35     * Elements are bits for bitstream formats, bytes otherwise.
36     */
37    uint16_t step_minus1  :3;
38
39    /**
40     * Number of elements before the component of the first pixel plus 1.
41     * Elements are bits for bitstream formats, bytes otherwise.
42     */
43    uint16_t offset_plus1 :3;
44    uint16_t shift        :3;            ///< number of least significant bits that must be shifted away to get the value
45    uint16_t depth_minus1 :4;            ///< number of bits in the component minus 1
46}AVComponentDescriptor;
47
48/**
49 * Descriptor that unambiguously describes how the bits of a pixel are
50 * stored in the up to 4 data planes of an image. It also stores the
51 * subsampling factors and number of components.
52 *
53 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
54 *       and all the YUV variants) AVPixFmtDescriptor just stores how values
55 *       are stored not what these values represent.
56 */
57typedef struct AVPixFmtDescriptor{
58    const char *name;
59    uint8_t nb_components;      ///< The number of components each pixel has, (1-4)
60
61    /**
62     * Amount to shift the luma width right to find the chroma width.
63     * For YV12 this is 1 for example.
64     * chroma_width = -((-luma_width) >> log2_chroma_w)
65     * The note above is needed to ensure rounding up.
66     * This value only refers to the chroma components.
67     */
68    uint8_t log2_chroma_w;      ///< chroma_width = -((-luma_width )>>log2_chroma_w)
69
70    /**
71     * Amount to shift the luma height right to find the chroma height.
72     * For YV12 this is 1 for example.
73     * chroma_height= -((-luma_height) >> log2_chroma_h)
74     * The note above is needed to ensure rounding up.
75     * This value only refers to the chroma components.
76     */
77    uint8_t log2_chroma_h;
78    uint8_t flags;
79
80    /**
81     * Parameters that describe how pixels are packed.
82     * If the format has 2 or 4 components, then alpha is last.
83     * If the format has 1 or 2 components, then luma is 0.
84     * If the format has 3 or 4 components,
85     * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
86     * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
87     */
88    AVComponentDescriptor comp[4];
89}AVPixFmtDescriptor;
90
91/**
92 * Pixel format is big-endian.
93 */
94#define AV_PIX_FMT_FLAG_BE           (1 << 0)
95/**
96 * Pixel format has a palette in data[1], values are indexes in this palette.
97 */
98#define AV_PIX_FMT_FLAG_PAL          (1 << 1)
99/**
100 * All values of a component are bit-wise packed end to end.
101 */
102#define AV_PIX_FMT_FLAG_BITSTREAM    (1 << 2)
103/**
104 * Pixel format is an HW accelerated format.
105 */
106#define AV_PIX_FMT_FLAG_HWACCEL      (1 << 3)
107/**
108 * At least one pixel component is not in the first data plane.
109 */
110#define AV_PIX_FMT_FLAG_PLANAR       (1 << 4)
111/**
112 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
113 */
114#define AV_PIX_FMT_FLAG_RGB          (1 << 5)
115/**
116 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
117 * paletted internally, but the palette is generated by the decoder and is not
118 * stored in the file.
119 */
120#define AV_PIX_FMT_FLAG_PSEUDOPAL    (1 << 6)
121/**
122 * The pixel format has an alpha channel.
123 */
124#define AV_PIX_FMT_FLAG_ALPHA        (1 << 7)
125
126#if FF_API_PIX_FMT
127/**
128 * @deprecated use the AV_PIX_FMT_FLAG_* flags
129 */
130#define PIX_FMT_BE        AV_PIX_FMT_FLAG_BE
131#define PIX_FMT_PAL       AV_PIX_FMT_FLAG_PAL
132#define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM
133#define PIX_FMT_HWACCEL   AV_PIX_FMT_FLAG_HWACCEL
134#define PIX_FMT_PLANAR    AV_PIX_FMT_FLAG_PLANAR
135#define PIX_FMT_RGB       AV_PIX_FMT_FLAG_RGB
136#define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
137#define PIX_FMT_ALPHA     AV_PIX_FMT_FLAG_ALPHA
138#endif
139
140#if FF_API_PIX_FMT_DESC
141/**
142 * The array of all the pixel format descriptors.
143 */
144extern attribute_deprecated const AVPixFmtDescriptor av_pix_fmt_descriptors[];
145#endif
146
147/**
148 * Read a line from an image, and write the values of the
149 * pixel format component c to dst.
150 *
151 * @param data the array containing the pointers to the planes of the image
152 * @param linesize the array containing the linesizes of the image
153 * @param desc the pixel format descriptor for the image
154 * @param x the horizontal coordinate of the first pixel to read
155 * @param y the vertical coordinate of the first pixel to read
156 * @param w the width of the line to read, that is the number of
157 * values to write to dst
158 * @param read_pal_component if not zero and the format is a paletted
159 * format writes the values corresponding to the palette
160 * component c in data[1] to dst, rather than the palette indexes in
161 * data[0]. The behavior is undefined if the format is not paletted.
162 */
163void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
164                        const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
165
166/**
167 * Write the values from src to the pixel format component c of an
168 * image line.
169 *
170 * @param src array containing the values to write
171 * @param data the array containing the pointers to the planes of the
172 * image to write into. It is supposed to be zeroed.
173 * @param linesize the array containing the linesizes of the image
174 * @param desc the pixel format descriptor for the image
175 * @param x the horizontal coordinate of the first pixel to write
176 * @param y the vertical coordinate of the first pixel to write
177 * @param w the width of the line to write, that is the number of
178 * values to write to the image line
179 */
180void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
181                         const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
182
183/**
184 * Return the pixel format corresponding to name.
185 *
186 * If there is no pixel format with name name, then looks for a
187 * pixel format with the name corresponding to the native endian
188 * format of name.
189 * For example in a little-endian system, first looks for "gray16",
190 * then for "gray16le".
191 *
192 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
193 */
194enum AVPixelFormat av_get_pix_fmt(const char *name);
195
196/**
197 * Return the short name for a pixel format, NULL in case pix_fmt is
198 * unknown.
199 *
200 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
201 */
202const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
203
204/**
205 * Print in buf the string corresponding to the pixel format with
206 * number pix_fmt, or a header if pix_fmt is negative.
207 *
208 * @param buf the buffer where to write the string
209 * @param buf_size the size of buf
210 * @param pix_fmt the number of the pixel format to print the
211 * corresponding info string, or a negative value to print the
212 * corresponding header.
213 */
214char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
215
216/**
217 * Return the number of bits per pixel used by the pixel format
218 * described by pixdesc. Note that this is not the same as the number
219 * of bits per sample.
220 *
221 * The returned number of bits refers to the number of bits actually
222 * used for storing the pixel information, that is padding bits are
223 * not counted.
224 */
225int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
226
227/**
228 * Return the number of bits per pixel for the pixel format
229 * described by pixdesc, including any padding or unused bits.
230 */
231int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
232
233/**
234 * @return a pixel format descriptor for provided pixel format or NULL if
235 * this pixel format is unknown.
236 */
237const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
238
239/**
240 * Iterate over all pixel format descriptors known to libavutil.
241 *
242 * @param prev previous descriptor. NULL to get the first descriptor.
243 *
244 * @return next descriptor or NULL after the last descriptor
245 */
246const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
247
248/**
249 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
250 * is not a valid pointer to a pixel format descriptor.
251 */
252enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
253
254/**
255 * Utility function to access log2_chroma_w log2_chroma_h from
256 * the pixel format AVPixFmtDescriptor.
257 *
258 * See av_get_chroma_sub_sample() for a function that asserts a
259 * valid pixel format instead of returning an error code.
260 * Its recommended that you use avcodec_get_chroma_sub_sample unless
261 * you do check the return code!
262 *
263 * @param[in]  pix_fmt the pixel format
264 * @param[out] h_shift store log2_chroma_w
265 * @param[out] v_shift store log2_chroma_h
266 *
267 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
268 */
269int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
270                                     int *h_shift, int *v_shift);
271
272/**
273 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
274 * valid pixel format.
275 */
276int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
277
278void ff_check_pixfmt_descriptors(void);
279
280/**
281 * Utility function to swap the endianness of a pixel format.
282 *
283 * @param[in]  pix_fmt the pixel format
284 *
285 * @return pixel format with swapped endianness if it exists,
286 * otherwise AV_PIX_FMT_NONE
287 */
288enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
289
290#define FF_LOSS_RESOLUTION  0x0001 /**< loss due to resolution change */
291#define FF_LOSS_DEPTH       0x0002 /**< loss due to color depth change */
292#define FF_LOSS_COLORSPACE  0x0004 /**< loss due to color space conversion */
293#define FF_LOSS_ALPHA       0x0008 /**< loss of alpha bits */
294#define FF_LOSS_COLORQUANT  0x0010 /**< loss due to color quantization */
295#define FF_LOSS_CHROMA      0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
296
297/**
298 * Compute what kind of losses will occur when converting from one specific
299 * pixel format to another.
300 * When converting from one pixel format to another, information loss may occur.
301 * For example, when converting from RGB24 to GRAY, the color information will
302 * be lost. Similarly, other losses occur when converting from some formats to
303 * other formats. These losses can involve loss of chroma, but also loss of
304 * resolution, loss of color depth, loss due to the color space conversion, loss
305 * of the alpha bits or loss due to color quantization.
306 * av_get_fix_fmt_loss() informs you about the various types of losses
307 * which will occur when converting from one pixel format to another.
308 *
309 * @param[in] dst_pix_fmt destination pixel format
310 * @param[in] src_pix_fmt source pixel format
311 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
312 * @return Combination of flags informing you what kind of losses will occur
313 * (maximum loss for an invalid dst_pix_fmt).
314 */
315int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
316                        enum AVPixelFormat src_pix_fmt,
317                        int has_alpha);
318
319/**
320 * Compute what kind of losses will occur when converting from one specific
321 * pixel format to another.
322 * When converting from one pixel format to another, information loss may occur.
323 * For example, when converting from RGB24 to GRAY, the color information will
324 * be lost. Similarly, other losses occur when converting from some formats to
325 * other formats. These losses can involve loss of chroma, but also loss of
326 * resolution, loss of color depth, loss due to the color space conversion, loss
327 * of the alpha bits or loss due to color quantization.
328 * av_get_fix_fmt_loss() informs you about the various types of losses
329 * which will occur when converting from one pixel format to another.
330 *
331 * @param[in] dst_pix_fmt destination pixel format
332 * @param[in] src_pix_fmt source pixel format
333 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
334 * @return Combination of flags informing you what kind of losses will occur
335 * (maximum loss for an invalid dst_pix_fmt).
336 */
337enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
338                                             enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
339#endif /* AVUTIL_PIXDESC_H */
340