2 * pixel format descriptor
3 * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
5 * This file is part of FFmpeg.
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.
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.
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
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.
94 * If the format has 2 or 4 components, then alpha is last.
95 * If the format has 1 or 2 components, then luma is 0.
96 * If the format has 3 or 4 components,
97 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
98 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
100 AVComponentDescriptor comp[4];
103 * Alternative comma-separated names.
106 } AVPixFmtDescriptor;
109 * Pixel format is big-endian.
111 #define AV_PIX_FMT_FLAG_BE (1 << 0)
113 * Pixel format has a palette in data[1], values are indexes in this palette.
115 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
117 * All values of a component are bit-wise packed end to end.
119 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
121 * Pixel format is an HW accelerated format.
123 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
125 * At least one pixel component is not in the first data plane.
127 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
129 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
131 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
134 * The pixel format is "pseudo-paletted". This means that it contains a
135 * fixed palette in the 2nd plane but the palette is fixed/constant for each
136 * PIX_FMT. This allows interpreting the data as if it was PAL8, which can
137 * in some cases be simpler. Or the data can be interpreted purely based on
138 * the pixel format without using the palette.
139 * An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
141 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
144 * The pixel format has an alpha channel. This is set on all formats that
145 * support alpha in some way. The exception is AV_PIX_FMT_PAL8, which can
146 * carry alpha as part of the palette. Details are explained in the
147 * AVPixelFormat enum, and are also encoded in the corresponding
148 * AVPixFmtDescriptor.
150 * The alpha is always straight, never pre-multiplied.
152 * If a codec or a filter does not support alpha, it should set all alpha to
153 * opaque, or use the equivalent pixel formats without alpha component, e.g.
154 * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
156 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
160 * @deprecated use the AV_PIX_FMT_FLAG_* flags
162 #define PIX_FMT_BE AV_PIX_FMT_FLAG_BE
163 #define PIX_FMT_PAL AV_PIX_FMT_FLAG_PAL
164 #define PIX_FMT_BITSTREAM AV_PIX_FMT_FLAG_BITSTREAM
165 #define PIX_FMT_HWACCEL AV_PIX_FMT_FLAG_HWACCEL
166 #define PIX_FMT_PLANAR AV_PIX_FMT_FLAG_PLANAR
167 #define PIX_FMT_RGB AV_PIX_FMT_FLAG_RGB
168 #define PIX_FMT_PSEUDOPAL AV_PIX_FMT_FLAG_PSEUDOPAL
169 #define PIX_FMT_ALPHA AV_PIX_FMT_FLAG_ALPHA
172 #if FF_API_PIX_FMT_DESC
174 * The array of all the pixel format descriptors.
176 extern attribute_deprecated const AVPixFmtDescriptor av_pix_fmt_descriptors[];
180 * Read a line from an image, and write the values of the
181 * pixel format component c to dst.
183 * @param data the array containing the pointers to the planes of the image
184 * @param linesize the array containing the linesizes of the image
185 * @param desc the pixel format descriptor for the image
186 * @param x the horizontal coordinate of the first pixel to read
187 * @param y the vertical coordinate of the first pixel to read
188 * @param w the width of the line to read, that is the number of
189 * values to write to dst
190 * @param read_pal_component if not zero and the format is a paletted
191 * format writes the values corresponding to the palette
192 * component c in data[1] to dst, rather than the palette indexes in
193 * data[0]. The behavior is undefined if the format is not paletted.
195 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
196 const int linesize[4], const AVPixFmtDescriptor *desc,
197 int x, int y, int c, int w, int read_pal_component);
200 * Write the values from src to the pixel format component c of an
203 * @param src array containing the values to write
204 * @param data the array containing the pointers to the planes of the
205 * image to write into. It is supposed to be zeroed.
206 * @param linesize the array containing the linesizes of the image
207 * @param desc the pixel format descriptor for the image
208 * @param x the horizontal coordinate of the first pixel to write
209 * @param y the vertical coordinate of the first pixel to write
210 * @param w the width of the line to write, that is the number of
211 * values to write to the image line
213 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
214 const int linesize[4], const AVPixFmtDescriptor *desc,
215 int x, int y, int c, int w);
218 * Return the pixel format corresponding to name.
220 * If there is no pixel format with name name, then looks for a
221 * pixel format with the name corresponding to the native endian
223 * For example in a little-endian system, first looks for "gray16",
224 * then for "gray16le".
226 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
228 enum AVPixelFormat av_get_pix_fmt(const char *name);
231 * Return the short name for a pixel format, NULL in case pix_fmt is
234 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
236 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
239 * Print in buf the string corresponding to the pixel format with
240 * number pix_fmt, or a header if pix_fmt is negative.
242 * @param buf the buffer where to write the string
243 * @param buf_size the size of buf
244 * @param pix_fmt the number of the pixel format to print the
245 * corresponding info string, or a negative value to print the
246 * corresponding header.
248 char *av_get_pix_fmt_string(char *buf, int buf_size,
249 enum AVPixelFormat pix_fmt);
252 * Return the number of bits per pixel used by the pixel format
253 * described by pixdesc. Note that this is not the same as the number
254 * of bits per sample.
256 * The returned number of bits refers to the number of bits actually
257 * used for storing the pixel information, that is padding bits are
260 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
263 * Return the number of bits per pixel for the pixel format
264 * described by pixdesc, including any padding or unused bits.
266 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
269 * @return a pixel format descriptor for provided pixel format or NULL if
270 * this pixel format is unknown.
272 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
275 * Iterate over all pixel format descriptors known to libavutil.
277 * @param prev previous descriptor. NULL to get the first descriptor.
279 * @return next descriptor or NULL after the last descriptor
281 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
284 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
285 * is not a valid pointer to a pixel format descriptor.
287 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
290 * Utility function to access log2_chroma_w log2_chroma_h from
291 * the pixel format AVPixFmtDescriptor.
293 * See av_get_chroma_sub_sample() for a function that asserts a
294 * valid pixel format instead of returning an error code.
295 * Its recommended that you use avcodec_get_chroma_sub_sample unless
296 * you do check the return code!
298 * @param[in] pix_fmt the pixel format
299 * @param[out] h_shift store log2_chroma_w
300 * @param[out] v_shift store log2_chroma_h
302 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
304 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
305 int *h_shift, int *v_shift);
308 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
309 * valid pixel format.
311 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
314 * Utility function to swap the endianness of a pixel format.
316 * @param[in] pix_fmt the pixel format
318 * @return pixel format with swapped endianness if it exists,
319 * otherwise AV_PIX_FMT_NONE
321 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
323 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
324 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
325 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
326 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
327 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
328 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
331 * Compute what kind of losses will occur when converting from one specific
332 * pixel format to another.
333 * When converting from one pixel format to another, information loss may occur.
334 * For example, when converting from RGB24 to GRAY, the color information will
335 * be lost. Similarly, other losses occur when converting from some formats to
336 * other formats. These losses can involve loss of chroma, but also loss of
337 * resolution, loss of color depth, loss due to the color space conversion, loss
338 * of the alpha bits or loss due to color quantization.
339 * av_get_fix_fmt_loss() informs you about the various types of losses
340 * which will occur when converting from one pixel format to another.
342 * @param[in] dst_pix_fmt destination pixel format
343 * @param[in] src_pix_fmt source pixel format
344 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
345 * @return Combination of flags informing you what kind of losses will occur
346 * (maximum loss for an invalid dst_pix_fmt).
348 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
349 enum AVPixelFormat src_pix_fmt,
353 * Compute what kind of losses will occur when converting from one specific
354 * pixel format to another.
355 * When converting from one pixel format to another, information loss may occur.
356 * For example, when converting from RGB24 to GRAY, the color information will
357 * be lost. Similarly, other losses occur when converting from some formats to
358 * other formats. These losses can involve loss of chroma, but also loss of
359 * resolution, loss of color depth, loss due to the color space conversion, loss
360 * of the alpha bits or loss due to color quantization.
361 * av_get_fix_fmt_loss() informs you about the various types of losses
362 * which will occur when converting from one pixel format to another.
364 * @param[in] dst_pix_fmt destination pixel format
365 * @param[in] src_pix_fmt source pixel format
366 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
367 * @return Combination of flags informing you what kind of losses will occur
368 * (maximum loss for an invalid dst_pix_fmt).
370 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
371 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
374 * @return the name for provided color range or NULL if unknown.
376 const char *av_color_range_name(enum AVColorRange range);
379 * @return the name for provided color primaries or NULL if unknown.
381 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
384 * @return the name for provided color transfer or NULL if unknown.
386 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
389 * @return the name for provided color space or NULL if unknown.
391 const char *av_color_space_name(enum AVColorSpace space);
394 * @return the name for provided chroma location or NULL if unknown.
396 const char *av_chroma_location_name(enum AVChromaLocation location);
398 #endif /* AVUTIL_PIXDESC_H */