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 {
32 * Which of the 4 planes contains the component.
37 * Number of elements between 2 horizontally consecutive pixels minus 1.
38 * Elements are bits for bitstream formats, bytes otherwise.
40 uint16_t step_minus1 : 3;
43 * Number of elements before the component of the first pixel plus 1.
44 * Elements are bits for bitstream formats, bytes otherwise.
46 uint16_t offset_plus1 : 3;
49 * Number of least significant bits that must be shifted away
55 * Number of bits in the component minus 1.
57 uint16_t depth_minus1 : 4;
58 } AVComponentDescriptor;
61 * Descriptor that unambiguously describes how the bits of a pixel are
62 * stored in the up to 4 data planes of an image. It also stores the
63 * subsampling factors and number of components.
65 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
66 * and all the YUV variants) AVPixFmtDescriptor just stores how values
67 * are stored not what these values represent.
69 typedef struct AVPixFmtDescriptor {
71 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
74 * Amount to shift the luma width right to find the chroma width.
75 * For YV12 this is 1 for example.
76 * chroma_width = -((-luma_width) >> log2_chroma_w)
77 * The note above is needed to ensure rounding up.
78 * This value only refers to the chroma components.
80 uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
83 * Amount to shift the luma height right to find the chroma height.
84 * For YV12 this is 1 for example.
85 * chroma_height= -((-luma_height) >> log2_chroma_h)
86 * The note above is needed to ensure rounding up.
87 * This value only refers to the chroma components.
89 uint8_t log2_chroma_h;
93 * Parameters that describe how pixels are packed. If the format
94 * has chroma components, they must be stored in comp[1] and
97 AVComponentDescriptor comp[4];
100 * Alternative comma-separated names.
103 } AVPixFmtDescriptor;
106 * Pixel format is big-endian.
108 #define AV_PIX_FMT_FLAG_BE (1 << 0)
110 * Pixel format has a palette in data[1], values are indexes in this palette.
112 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
114 * All values of a component are bit-wise packed end to end.
116 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
118 * Pixel format is an HW accelerated format.
120 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
122 * At least one pixel component is not in the first data plane.
124 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
126 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
128 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
130 * The pixel format is "pseudo-paletted". This means that Libav treats it as
131 * paletted internally, but the palette is generated by the decoder and is not
132 * stored in the file.
134 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
136 * The pixel format has an alpha channel.
138 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
141 * Read a line from an image, and write the values of the
142 * pixel format component c to dst.
144 * @param data the array containing the pointers to the planes of the image
145 * @param linesize the array containing the linesizes of the image
146 * @param desc the pixel format descriptor for the image
147 * @param x the horizontal coordinate of the first pixel to read
148 * @param y the vertical coordinate of the first pixel to read
149 * @param w the width of the line to read, that is the number of
150 * values to write to dst
151 * @param read_pal_component if not zero and the format is a paletted
152 * format writes the values corresponding to the palette
153 * component c in data[1] to dst, rather than the palette indexes in
154 * data[0]. The behavior is undefined if the format is not paletted.
156 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
157 const int linesize[4], const AVPixFmtDescriptor *desc,
158 int x, int y, int c, int w, int read_pal_component);
161 * Write the values from src to the pixel format component c of an
164 * @param src array containing the values to write
165 * @param data the array containing the pointers to the planes of the
166 * image to write into. It is supposed to be zeroed.
167 * @param linesize the array containing the linesizes of the image
168 * @param desc the pixel format descriptor for the image
169 * @param x the horizontal coordinate of the first pixel to write
170 * @param y the vertical coordinate of the first pixel to write
171 * @param w the width of the line to write, that is the number of
172 * values to write to the image line
174 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
175 const int linesize[4], const AVPixFmtDescriptor *desc,
176 int x, int y, int c, int w);
179 * Return the pixel format corresponding to name.
181 * If there is no pixel format with name name, then looks for a
182 * pixel format with the name corresponding to the native endian
184 * For example in a little-endian system, first looks for "gray16",
185 * then for "gray16le".
187 * Finally if no pixel format has been found, returns PIX_FMT_NONE.
189 enum AVPixelFormat av_get_pix_fmt(const char *name);
192 * Return the short name for a pixel format, NULL in case pix_fmt is
195 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
197 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
200 * Print in buf the string corresponding to the pixel format with
201 * number pix_fmt, or an header if pix_fmt is negative.
203 * @param buf the buffer where to write the string
204 * @param buf_size the size of buf
205 * @param pix_fmt the number of the pixel format to print the
206 * corresponding info string, or a negative value to print the
207 * corresponding header.
209 char *av_get_pix_fmt_string(char *buf, int buf_size,
210 enum AVPixelFormat pix_fmt);
213 * Return the number of bits per pixel used by the pixel format
214 * described by pixdesc. Note that this is not the same as the number
215 * of bits per sample.
217 * The returned number of bits refers to the number of bits actually
218 * used for storing the pixel information, that is padding bits are
221 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
224 * @return a pixel format descriptor for provided pixel format or NULL if
225 * this pixel format is unknown.
227 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
230 * Iterate over all pixel format descriptors known to libavutil.
232 * @param prev previous descriptor. NULL to get the first descriptor.
234 * @return next descriptor or NULL after the last descriptor
236 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
239 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
240 * is not a valid pointer to a pixel format descriptor.
242 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
245 * Utility function to access log2_chroma_w log2_chroma_h from
246 * the pixel format AVPixFmtDescriptor.
248 * @param[in] pix_fmt the pixel format
249 * @param[out] h_shift store log2_chroma_h
250 * @param[out] v_shift store log2_chroma_w
252 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
254 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
255 int *h_shift, int *v_shift);
258 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
259 * valid pixel format.
261 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
264 * Utility function to swap the endianness of a pixel format.
266 * @param[in] pix_fmt the pixel format
268 * @return pixel format with swapped endianness if it exists,
269 * otherwise AV_PIX_FMT_NONE
271 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
274 * @return the name for provided color range or NULL if unknown.
276 const char *av_color_range_name(enum AVColorRange range);
279 * @return the name for provided color primaries or NULL if unknown.
281 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
284 * @return the name for provided color transfer or NULL if unknown.
286 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
289 * @return the name for provided color space or NULL if unknown.
291 const char *av_color_space_name(enum AVColorSpace space);
294 * @return the name for provided chroma location or NULL if unknown.
296 const char *av_chroma_location_name(enum AVChromaLocation location);
298 #endif /* AVUTIL_PIXDESC_H */