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"
31 typedef struct AVComponentDescriptor {
33 * Which of the 4 planes contains the component.
38 * Number of elements between 2 horizontally consecutive pixels.
39 * Elements are bits for bitstream formats, bytes otherwise.
44 * Number of elements before the component of the first pixel.
45 * Elements are bits for bitstream formats, bytes otherwise.
50 * Number of least significant bits that must be shifted away
56 * Number of bits in the component.
60 #if FF_API_PLUS1_MINUS1
61 /** deprecated, use step instead */
62 attribute_deprecated int step_minus1;
64 /** deprecated, use depth instead */
65 attribute_deprecated int depth_minus1;
67 /** deprecated, use offset instead */
68 attribute_deprecated int offset_plus1;
70 } AVComponentDescriptor;
73 * Descriptor that unambiguously describes how the bits of a pixel are
74 * stored in the up to 4 data planes of an image. It also stores the
75 * subsampling factors and number of components.
77 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
78 * and all the YUV variants) AVPixFmtDescriptor just stores how values
79 * are stored not what these values represent.
81 typedef struct AVPixFmtDescriptor {
83 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
86 * Amount to shift the luma width right to find the chroma width.
87 * For YV12 this is 1 for example.
88 * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
89 * The note above is needed to ensure rounding up.
90 * This value only refers to the chroma components.
92 uint8_t log2_chroma_w;
95 * Amount to shift the luma height right to find the chroma height.
96 * For YV12 this is 1 for example.
97 * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
98 * The note above is needed to ensure rounding up.
99 * This value only refers to the chroma components.
101 uint8_t log2_chroma_h;
104 * Combination of AV_PIX_FMT_FLAG_... flags.
109 * Parameters that describe how pixels are packed.
110 * If the format has 1 or 2 components, then luma is 0.
111 * If the format has 3 or 4 components:
112 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
113 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
115 * If present, the Alpha channel is always the last component.
117 AVComponentDescriptor comp[4];
120 * Alternative comma-separated names.
123 } AVPixFmtDescriptor;
126 * Pixel format is big-endian.
128 #define AV_PIX_FMT_FLAG_BE (1 << 0)
130 * Pixel format has a palette in data[1], values are indexes in this palette.
132 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
134 * All values of a component are bit-wise packed end to end.
136 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
138 * Pixel format is an HW accelerated format.
140 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
142 * At least one pixel component is not in the first data plane.
144 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
146 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
148 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
151 * The pixel format is "pseudo-paletted". This means that it contains a
152 * fixed palette in the 2nd plane but the palette is fixed/constant for each
153 * PIX_FMT. This allows interpreting the data as if it was PAL8, which can
154 * in some cases be simpler. Or the data can be interpreted purely based on
155 * the pixel format without using the palette.
156 * An example of a pseudo-paletted format is AV_PIX_FMT_GRAY8
158 * @deprecated This flag is deprecated, and will be removed. When it is removed,
159 * the extra palette allocation in AVFrame.data[1] is removed as well. Only
160 * actual paletted formats (as indicated by AV_PIX_FMT_FLAG_PAL) will have a
161 * palette. Starting with FFmpeg versions which have this flag deprecated, the
162 * extra "pseudo" palette is already ignored, and API users are not required to
163 * allocate a palette for AV_PIX_FMT_FLAG_PSEUDOPAL formats (it was required
164 * before the deprecation, though).
166 #define AV_PIX_FMT_FLAG_PSEUDOPAL (1 << 6)
169 * The pixel format has an alpha channel. This is set on all formats that
170 * support alpha in some way. The exception is AV_PIX_FMT_PAL8, which can
171 * carry alpha as part of the palette. Details are explained in the
172 * AVPixelFormat enum, and are also encoded in the corresponding
173 * AVPixFmtDescriptor.
175 * The alpha is always straight, never pre-multiplied.
177 * If a codec or a filter does not support alpha, it should set all alpha to
178 * opaque, or use the equivalent pixel formats without alpha component, e.g.
179 * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
181 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
184 * The pixel format is following a Bayer pattern
186 #define AV_PIX_FMT_FLAG_BAYER (1 << 8)
189 * The pixel format contains IEEE-754 floating point values. Precision (double,
190 * single, or half) should be determined by the pixel size (64, 32, or 16 bits).
192 #define AV_PIX_FMT_FLAG_FLOAT (1 << 9)
195 * Return the number of bits per pixel used by the pixel format
196 * described by pixdesc. Note that this is not the same as the number
197 * of bits per sample.
199 * The returned number of bits refers to the number of bits actually
200 * used for storing the pixel information, that is padding bits are
203 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
206 * Return the number of bits per pixel for the pixel format
207 * described by pixdesc, including any padding or unused bits.
209 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
212 * @return a pixel format descriptor for provided pixel format or NULL if
213 * this pixel format is unknown.
215 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
218 * Iterate over all pixel format descriptors known to libavutil.
220 * @param prev previous descriptor. NULL to get the first descriptor.
222 * @return next descriptor or NULL after the last descriptor
224 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
227 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
228 * is not a valid pointer to a pixel format descriptor.
230 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
233 * Utility function to access log2_chroma_w log2_chroma_h from
234 * the pixel format AVPixFmtDescriptor.
236 * @param[in] pix_fmt the pixel format
237 * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
238 * @param[out] v_shift store log2_chroma_h (vertical/height shift)
240 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
242 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
243 int *h_shift, int *v_shift);
246 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
247 * valid pixel format.
249 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
252 * @return the name for provided color range or NULL if unknown.
254 const char *av_color_range_name(enum AVColorRange range);
257 * @return the AVColorRange value for name or an AVError if not found.
259 int av_color_range_from_name(const char *name);
262 * @return the name for provided color primaries or NULL if unknown.
264 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
267 * @return the AVColorPrimaries value for name or an AVError if not found.
269 int av_color_primaries_from_name(const char *name);
272 * @return the name for provided color transfer or NULL if unknown.
274 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
277 * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
279 int av_color_transfer_from_name(const char *name);
282 * @return the name for provided color space or NULL if unknown.
284 const char *av_color_space_name(enum AVColorSpace space);
287 * @return the AVColorSpace value for name or an AVError if not found.
289 int av_color_space_from_name(const char *name);
292 * @return the name for provided chroma location or NULL if unknown.
294 const char *av_chroma_location_name(enum AVChromaLocation location);
297 * @return the AVChromaLocation value for name or an AVError if not found.
299 int av_chroma_location_from_name(const char *name);
302 * Return the pixel format corresponding to name.
304 * If there is no pixel format with name name, then looks for a
305 * pixel format with the name corresponding to the native endian
307 * For example in a little-endian system, first looks for "gray16",
308 * then for "gray16le".
310 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
312 enum AVPixelFormat av_get_pix_fmt(const char *name);
315 * Return the short name for a pixel format, NULL in case pix_fmt is
318 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
320 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
323 * Print in buf the string corresponding to the pixel format with
324 * number pix_fmt, or a header if pix_fmt is negative.
326 * @param buf the buffer where to write the string
327 * @param buf_size the size of buf
328 * @param pix_fmt the number of the pixel format to print the
329 * corresponding info string, or a negative value to print the
330 * corresponding header.
332 char *av_get_pix_fmt_string(char *buf, int buf_size,
333 enum AVPixelFormat pix_fmt);
336 * Read a line from an image, and write the values of the
337 * pixel format component c to dst.
339 * @param data the array containing the pointers to the planes of the image
340 * @param linesize the array containing the linesizes of the image
341 * @param desc the pixel format descriptor for the image
342 * @param x the horizontal coordinate of the first pixel to read
343 * @param y the vertical coordinate of the first pixel to read
344 * @param w the width of the line to read, that is the number of
345 * values to write to dst
346 * @param read_pal_component if not zero and the format is a paletted
347 * format writes the values corresponding to the palette
348 * component c in data[1] to dst, rather than the palette indexes in
349 * data[0]. The behavior is undefined if the format is not paletted.
351 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
352 const int linesize[4], const AVPixFmtDescriptor *desc,
353 int x, int y, int c, int w, int read_pal_component);
356 * Write the values from src to the pixel format component c of an
359 * @param src array containing the values to write
360 * @param data the array containing the pointers to the planes of the
361 * image to write into. It is supposed to be zeroed.
362 * @param linesize the array containing the linesizes of the image
363 * @param desc the pixel format descriptor for the image
364 * @param x the horizontal coordinate of the first pixel to write
365 * @param y the vertical coordinate of the first pixel to write
366 * @param w the width of the line to write, that is the number of
367 * values to write to the image line
369 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
370 const int linesize[4], const AVPixFmtDescriptor *desc,
371 int x, int y, int c, int w);
374 * Utility function to swap the endianness of a pixel format.
376 * @param[in] pix_fmt the pixel format
378 * @return pixel format with swapped endianness if it exists,
379 * otherwise AV_PIX_FMT_NONE
381 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
383 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
384 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
385 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
386 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
387 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
388 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
391 * Compute what kind of losses will occur when converting from one specific
392 * pixel format to another.
393 * When converting from one pixel format to another, information loss may occur.
394 * For example, when converting from RGB24 to GRAY, the color information will
395 * be lost. Similarly, other losses occur when converting from some formats to
396 * other formats. These losses can involve loss of chroma, but also loss of
397 * resolution, loss of color depth, loss due to the color space conversion, loss
398 * of the alpha bits or loss due to color quantization.
399 * av_get_fix_fmt_loss() informs you about the various types of losses
400 * which will occur when converting from one pixel format to another.
402 * @param[in] dst_pix_fmt destination pixel format
403 * @param[in] src_pix_fmt source pixel format
404 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
405 * @return Combination of flags informing you what kind of losses will occur
406 * (maximum loss for an invalid dst_pix_fmt).
408 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
409 enum AVPixelFormat src_pix_fmt,
413 * Compute what kind of losses will occur when converting from one specific
414 * pixel format to another.
415 * When converting from one pixel format to another, information loss may occur.
416 * For example, when converting from RGB24 to GRAY, the color information will
417 * be lost. Similarly, other losses occur when converting from some formats to
418 * other formats. These losses can involve loss of chroma, but also loss of
419 * resolution, loss of color depth, loss due to the color space conversion, loss
420 * of the alpha bits or loss due to color quantization.
421 * av_get_fix_fmt_loss() informs you about the various types of losses
422 * which will occur when converting from one pixel format to another.
424 * @param[in] dst_pix_fmt destination pixel format
425 * @param[in] src_pix_fmt source pixel format
426 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
427 * @return Combination of flags informing you what kind of losses will occur
428 * (maximum loss for an invalid dst_pix_fmt).
430 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
431 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
433 #endif /* AVUTIL_PIXDESC_H */