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preparation for libavcodec
author zipi
date Tue, 31 Dec 2013 14:52:14 +0000
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2133:e378232bfd36 2134:992d2e6f907d
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 <stdint.h>
26 #include "pixfmt.h"
27
28 typedef struct AVComponentDescriptor{
29 uint16_t plane :2; ///< which of the 4 planes contains the component
30
31 /**
32 * Number of elements between 2 horizontally consecutive pixels minus 1.
33 * Elements are bits for bitstream formats, bytes otherwise.
34 */
35 uint16_t step_minus1 :3;
36
37 /**
38 * Number of elements before the component of the first pixel plus 1.
39 * Elements are bits for bitstream formats, bytes otherwise.
40 */
41 uint16_t offset_plus1 :3;
42 uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
43 uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
44 }AVComponentDescriptor;
45
46 /**
47 * Descriptor that unambiguously describes how the bits of a pixel are
48 * stored in the up to 4 data planes of an image. It also stores the
49 * subsampling factors and number of components.
50 *
51 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
52 * and all the YUV variants) AVPixFmtDescriptor just stores how values
53 * are stored not what these values represent.
54 */
55 typedef struct AVPixFmtDescriptor{
56 const char *name;
57 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
58
59 /**
60 * Amount to shift the luma width right to find the chroma width.
61 * For YV12 this is 1 for example.
62 * chroma_width = -((-luma_width) >> log2_chroma_w)
63 * The note above is needed to ensure rounding up.
64 * This value only refers to the chroma components.
65 */
66 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
67
68 /**
69 * Amount to shift the luma height right to find the chroma height.
70 * For YV12 this is 1 for example.
71 * chroma_height= -((-luma_height) >> log2_chroma_h)
72 * The note above is needed to ensure rounding up.
73 * This value only refers to the chroma components.
74 */
75 uint8_t log2_chroma_h;
76 uint8_t flags;
77
78 /**
79 * Parameters that describe how pixels are packed.
80 * If the format has 2 or 4 components, then alpha is last.
81 * If the format has 1 or 2 components, then luma is 0.
82 * If the format has 3 or 4 components,
83 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
84 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
85 */
86 AVComponentDescriptor comp[4];
87 }AVPixFmtDescriptor;
88
89 /**
90 * Pixel format is big-endian.
91 */
92 #define AV_PIX_FMT_FLAG_BE (1 << 0)
93 /**
94 * Pixel format has a palette in data[1], values are indexes in this palette.
95 */
96 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
97 /**
98 * All values of a component are bit-wise packed end to end.
99 */
100 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
101 /**
102 * Pixel format is an HW accelerated format.
103 */
104 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
105 /**
106 * At least one pixel component is not in the first data plane.
107 */
108 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
109 /**
110 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
111 */
112 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
113 /**
114 * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
115 * paletted internally, but the palette is generated by the decoder and is not
116 * stored in the file.
117 */
118 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
119 /**
120 * The pixel format has an alpha channel.
121 */
122 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
123
124 #if FF_API_PIX_FMT
125 /**
126 * @deprecate use the AV_PIX_FMT_FLAG_* flags
127 */
128 #define PIX_FMT_BE AV_PIX_FMT_FLAG_BE
129 #define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL
130 #define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM
131 #define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL
132 #define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR
133 #define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB
134 #define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
135 #define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA
136 #endif
137
138 #if FF_API_PIX_FMT_DESC
139 /**
140 * The array of all the pixel format descriptors.
141 */
142 extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
143 #endif
144
145 /**
146 * Read a line from an image, and write the values of the
147 * pixel format component c to dst.
148 *
149 * @param data the array containing the pointers to the planes of the image
150 * @param linesize the array containing the linesizes of the image
151 * @param desc the pixel format descriptor for the image
152 * @param x the horizontal coordinate of the first pixel to read
153 * @param y the vertical coordinate of the first pixel to read
154 * @param w the width of the line to read, that is the number of
155 * values to write to dst
156 * @param read_pal_component if not zero and the format is a paletted
157 * format writes the values corresponding to the palette
158 * component c in data[1] to dst, rather than the palette indexes in
159 * data[0]. The behavior is undefined if the format is not paletted.
160 */
161 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
162 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
163
164 /**
165 * Write the values from src to the pixel format component c of an
166 * image line.
167 *
168 * @param src array containing the values to write
169 * @param data the array containing the pointers to the planes of the
170 * image to write into. It is supposed to be zeroed.
171 * @param linesize the array containing the linesizes of the image
172 * @param desc the pixel format descriptor for the image
173 * @param x the horizontal coordinate of the first pixel to write
174 * @param y the vertical coordinate of the first pixel to write
175 * @param w the width of the line to write, that is the number of
176 * values to write to the image line
177 */
178 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
179 const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
180
181 /**
182 * Return the pixel format corresponding to name.
183 *
184 * If there is no pixel format with name name, then looks for a
185 * pixel format with the name corresponding to the native endian
186 * format of name.
187 * For example in a little-endian system, first looks for "gray16",
188 * then for "gray16le".
189 *
190 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
191 */
192 enum AVPixelFormat av_get_pix_fmt(const char *name);
193
194 /**
195 * Return the short name for a pixel format, NULL in case pix_fmt is
196 * unknown.
197 *
198 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
199 */
200 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
201
202 /**
203 * Print in buf the string corresponding to the pixel format with
204 * number pix_fmt, or an header if pix_fmt is negative.
205 *
206 * @param buf the buffer where to write the string
207 * @param buf_size the size of buf
208 * @param pix_fmt the number of the pixel format to print the
209 * corresponding info string, or a negative value to print the
210 * corresponding header.
211 */
212 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
213
214 /**
215 * Return the number of bits per pixel used by the pixel format
216 * described by pixdesc. Note that this is not the same as the number
217 * of bits per sample.
218 *
219 * The returned number of bits refers to the number of bits actually
220 * used for storing the pixel information, that is padding bits are
221 * not counted.
222 */
223 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
224
225 /**
226 * Return the number of bits per pixel for the pixel format
227 * described by pixdesc, including any padding or unused bits.
228 */
229 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
230
231 /**
232 * @return a pixel format descriptor for provided pixel format or NULL if
233 * this pixel format is unknown.
234 */
235 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
236
237 /**
238 * Iterate over all pixel format descriptors known to libavutil.
239 *
240 * @param prev previous descriptor. NULL to get the first descriptor.
241 *
242 * @return next descriptor or NULL after the last descriptor
243 */
244 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
245
246 /**
247 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
248 * is not a valid pointer to a pixel format descriptor.
249 */
250 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
251
252 /**
253 * Utility function to access log2_chroma_w log2_chroma_h from
254 * the pixel format AVPixFmtDescriptor.
255 *
256 * See avcodec_get_chroma_sub_sample() for a function that asserts a
257 * valid pixel format instead of returning an error code.
258 * Its recommanded that you use avcodec_get_chroma_sub_sample unless
259 * you do check the return code!
260 *
261 * @param[in] pix_fmt the pixel format
262 * @param[out] h_shift store log2_chroma_w
263 * @param[out] v_shift store log2_chroma_h
264 *
265 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
266 */
267 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
268 int *h_shift, int *v_shift);
269
270 /**
271 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
272 * valid pixel format.
273 */
274 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
275
276 void ff_check_pixfmt_descriptors(void);
277
278 /**
279 * Utility function to swap the endianness of a pixel format.
280 *
281 * @param[in] pix_fmt the pixel format
282 *
283 * @return pixel format with swapped endianness if it exists,
284 * otherwise AV_PIX_FMT_NONE
285 */
286 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
287
288
289 #endif /* AVUTIL_PIXDESC_H */