2 * pixel format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #ifndef AVUTIL_PIXDESC_H
23 #define AVUTIL_PIXDESC_H
27 #include "attributes.h"
30 typedef struct AVComponentDescriptor{
31 uint16_t plane :2; ///< which of the 4 planes contains the component
34 * Number of elements between 2 horizontally consecutive pixels minus 1.
35 * Elements are bits for bitstream formats, bytes otherwise.
37 uint16_t step_minus1 :3;
40 * Number of elements before the component of the first pixel plus 1.
41 * Elements are bits for bitstream formats, bytes otherwise.
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;
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.
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.
57 typedef struct AVPixFmtDescriptor{
59 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
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.
68 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
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.
77 uint8_t log2_chroma_h;
81 * Parameters that describe how pixels are packed. If the format
82 * has chroma components, they must be stored in comp[1] and
85 AVComponentDescriptor comp[4];
89 * Pixel format is big-endian.
91 #define AV_PIX_FMT_FLAG_BE (1 << 0)
93 * Pixel format has a palette in data[1], values are indexes in this palette.
95 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
97 * All values of a component are bit-wise packed end to end.
99 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
101 * Pixel format is an HW accelerated format.
103 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
105 * At least one pixel component is not in the first data plane.
107 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
109 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
111 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
113 * The pixel format is "pseudo-paletted". This means that Libav treats it as
114 * paletted internally, but the palette is generated by the decoder and is not
115 * stored in the file.
117 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
119 * The pixel format has an alpha channel.
121 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
125 * @deprecated use the AV_PIX_FMT_FLAG_* flags
127 #define PIX_FMT_BE AV_PIX_FMT_FLAG_BE
128 #define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL
129 #define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM
130 #define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL
131 #define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR
132 #define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB
133 #define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
134 #define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA
137 #if FF_API_PIX_FMT_DESC
139 * The array of all the pixel format descriptors.
141 extern attribute_deprecated const AVPixFmtDescriptor av_pix_fmt_descriptors[];
145 * Read a line from an image, and write the values of the
146 * pixel format component c to dst.
148 * @param data the array containing the pointers to the planes of the image
149 * @param linesize the array containing the linesizes of the image
150 * @param desc the pixel format descriptor for the image
151 * @param x the horizontal coordinate of the first pixel to read
152 * @param y the vertical coordinate of the first pixel to read
153 * @param w the width of the line to read, that is the number of
154 * values to write to dst
155 * @param read_pal_component if not zero and the format is a paletted
156 * format writes the values corresponding to the palette
157 * component c in data[1] to dst, rather than the palette indexes in
158 * data[0]. The behavior is undefined if the format is not paletted.
160 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
161 const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
164 * Write the values from src to the pixel format component c of an
167 * @param src array containing the values to write
168 * @param data the array containing the pointers to the planes of the
169 * image to write into. It is supposed to be zeroed.
170 * @param linesize the array containing the linesizes of the image
171 * @param desc the pixel format descriptor for the image
172 * @param x the horizontal coordinate of the first pixel to write
173 * @param y the vertical coordinate of the first pixel to write
174 * @param w the width of the line to write, that is the number of
175 * values to write to the image line
177 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
178 const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
181 * Return the pixel format corresponding to name.
183 * If there is no pixel format with name name, then looks for a
184 * pixel format with the name corresponding to the native endian
186 * For example in a little-endian system, first looks for "gray16",
187 * then for "gray16le".
189 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
191 enum AVPixelFormat av_get_pix_fmt(const char *name);
194 * Return the short name for a pixel format, NULL in case pix_fmt is
197 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
199 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
202 * Print in buf the string corresponding to the pixel format with
203 * number pix_fmt, or an header if pix_fmt is negative.
205 * @param buf the buffer where to write the string
206 * @param buf_size the size of buf
207 * @param pix_fmt the number of the pixel format to print the
208 * corresponding info string, or a negative value to print the
209 * corresponding header.
211 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
214 * Return the number of bits per pixel used by the pixel format
215 * described by pixdesc. Note that this is not the same as the number
216 * of bits per sample.
218 * The returned number of bits refers to the number of bits actually
219 * used for storing the pixel information, that is padding bits are
222 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
225 * @return a pixel format descriptor for provided pixel format or NULL if
226 * this pixel format is unknown.
228 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
231 * Iterate over all pixel format descriptors known to libavutil.
233 * @param prev previous descriptor. NULL to get the first descriptor.
235 * @return next descriptor or NULL after the last descriptor
237 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
240 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
241 * is not a valid pointer to a pixel format descriptor.
243 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
246 * Utility function to access log2_chroma_w log2_chroma_h from
247 * the pixel format AVPixFmtDescriptor.
249 * @param[in] pix_fmt the pixel format
250 * @param[out] h_shift store log2_chroma_h
251 * @param[out] v_shift store log2_chroma_w
253 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
255 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
256 int *h_shift, int *v_shift);
259 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
260 * valid pixel format.
262 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
266 * Utility function to swap the endianness of a pixel format.
268 * @param[in] pix_fmt the pixel format
270 * @return pixel format with swapped endianness if it exists,
271 * otherwise AV_PIX_FMT_NONE
273 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
276 #endif /* AVUTIL_PIXDESC_H */