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.
59 } AVComponentDescriptor;
62 * Descriptor that unambiguously describes how the bits of a pixel are
63 * stored in the up to 4 data planes of an image. It also stores the
64 * subsampling factors and number of components.
66 * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
67 * and all the YUV variants) AVPixFmtDescriptor just stores how values
68 * are stored not what these values represent.
70 typedef struct AVPixFmtDescriptor {
72 uint8_t nb_components; ///< The number of components each pixel has, (1-4)
75 * Amount to shift the luma width right to find the chroma width.
76 * For YV12 this is 1 for example.
77 * chroma_width = AV_CEIL_RSHIFT(luma_width, log2_chroma_w)
78 * The note above is needed to ensure rounding up.
79 * This value only refers to the chroma components.
81 uint8_t log2_chroma_w;
84 * Amount to shift the luma height right to find the chroma height.
85 * For YV12 this is 1 for example.
86 * chroma_height= AV_CEIL_RSHIFT(luma_height, log2_chroma_h)
87 * The note above is needed to ensure rounding up.
88 * This value only refers to the chroma components.
90 uint8_t log2_chroma_h;
93 * Combination of AV_PIX_FMT_FLAG_... flags.
98 * Parameters that describe how pixels are packed.
99 * If the format has 1 or 2 components, then luma is 0.
100 * If the format has 3 or 4 components:
101 * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
102 * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
104 * If present, the Alpha channel is always the last component.
106 AVComponentDescriptor comp[4];
109 * Alternative comma-separated names.
112 } AVPixFmtDescriptor;
115 * Pixel format is big-endian.
117 #define AV_PIX_FMT_FLAG_BE (1 << 0)
119 * Pixel format has a palette in data[1], values are indexes in this palette.
121 #define AV_PIX_FMT_FLAG_PAL (1 << 1)
123 * All values of a component are bit-wise packed end to end.
125 #define AV_PIX_FMT_FLAG_BITSTREAM (1 << 2)
127 * Pixel format is an HW accelerated format.
129 #define AV_PIX_FMT_FLAG_HWACCEL (1 << 3)
131 * At least one pixel component is not in the first data plane.
133 #define AV_PIX_FMT_FLAG_PLANAR (1 << 4)
135 * The pixel format contains RGB-like data (as opposed to YUV/grayscale).
137 #define AV_PIX_FMT_FLAG_RGB (1 << 5)
140 * The pixel format has an alpha channel. This is set on all formats that
141 * support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always
142 * straight, never pre-multiplied.
144 * If a codec or a filter does not support alpha, it should set all alpha to
145 * opaque, or use the equivalent pixel formats without alpha component, e.g.
146 * AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
148 #define AV_PIX_FMT_FLAG_ALPHA (1 << 7)
151 * The pixel format is following a Bayer pattern
153 #define AV_PIX_FMT_FLAG_BAYER (1 << 8)
156 * The pixel format contains IEEE-754 floating point values. Precision (double,
157 * single, or half) should be determined by the pixel size (64, 32, or 16 bits).
159 #define AV_PIX_FMT_FLAG_FLOAT (1 << 9)
162 * Return the number of bits per pixel used by the pixel format
163 * described by pixdesc. Note that this is not the same as the number
164 * of bits per sample.
166 * The returned number of bits refers to the number of bits actually
167 * used for storing the pixel information, that is padding bits are
170 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
173 * Return the number of bits per pixel for the pixel format
174 * described by pixdesc, including any padding or unused bits.
176 int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
179 * @return a pixel format descriptor for provided pixel format or NULL if
180 * this pixel format is unknown.
182 const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
185 * Iterate over all pixel format descriptors known to libavutil.
187 * @param prev previous descriptor. NULL to get the first descriptor.
189 * @return next descriptor or NULL after the last descriptor
191 const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
194 * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
195 * is not a valid pointer to a pixel format descriptor.
197 enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
200 * Utility function to access log2_chroma_w log2_chroma_h from
201 * the pixel format AVPixFmtDescriptor.
203 * @param[in] pix_fmt the pixel format
204 * @param[out] h_shift store log2_chroma_w (horizontal/width shift)
205 * @param[out] v_shift store log2_chroma_h (vertical/height shift)
207 * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
209 int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
210 int *h_shift, int *v_shift);
213 * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
214 * valid pixel format.
216 int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);
219 * @return the name for provided color range or NULL if unknown.
221 const char *av_color_range_name(enum AVColorRange range);
224 * @return the AVColorRange value for name or an AVError if not found.
226 int av_color_range_from_name(const char *name);
229 * @return the name for provided color primaries or NULL if unknown.
231 const char *av_color_primaries_name(enum AVColorPrimaries primaries);
234 * @return the AVColorPrimaries value for name or an AVError if not found.
236 int av_color_primaries_from_name(const char *name);
239 * @return the name for provided color transfer or NULL if unknown.
241 const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);
244 * @return the AVColorTransferCharacteristic value for name or an AVError if not found.
246 int av_color_transfer_from_name(const char *name);
249 * @return the name for provided color space or NULL if unknown.
251 const char *av_color_space_name(enum AVColorSpace space);
254 * @return the AVColorSpace value for name or an AVError if not found.
256 int av_color_space_from_name(const char *name);
259 * @return the name for provided chroma location or NULL if unknown.
261 const char *av_chroma_location_name(enum AVChromaLocation location);
264 * @return the AVChromaLocation value for name or an AVError if not found.
266 int av_chroma_location_from_name(const char *name);
269 * Return the pixel format corresponding to name.
271 * If there is no pixel format with name name, then looks for a
272 * pixel format with the name corresponding to the native endian
274 * For example in a little-endian system, first looks for "gray16",
275 * then for "gray16le".
277 * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
279 enum AVPixelFormat av_get_pix_fmt(const char *name);
282 * Return the short name for a pixel format, NULL in case pix_fmt is
285 * @see av_get_pix_fmt(), av_get_pix_fmt_string()
287 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
290 * Print in buf the string corresponding to the pixel format with
291 * number pix_fmt, or a header if pix_fmt is negative.
293 * @param buf the buffer where to write the string
294 * @param buf_size the size of buf
295 * @param pix_fmt the number of the pixel format to print the
296 * corresponding info string, or a negative value to print the
297 * corresponding header.
299 char *av_get_pix_fmt_string(char *buf, int buf_size,
300 enum AVPixelFormat pix_fmt);
303 * Read a line from an image, and write the values of the
304 * pixel format component c to dst.
306 * @param data the array containing the pointers to the planes of the image
307 * @param linesize the array containing the linesizes of the image
308 * @param desc the pixel format descriptor for the image
309 * @param x the horizontal coordinate of the first pixel to read
310 * @param y the vertical coordinate of the first pixel to read
311 * @param w the width of the line to read, that is the number of
312 * values to write to dst
313 * @param read_pal_component if not zero and the format is a paletted
314 * format writes the values corresponding to the palette
315 * component c in data[1] to dst, rather than the palette indexes in
316 * data[0]. The behavior is undefined if the format is not paletted.
317 * @param dst_element_size size of elements in dst array (2 or 4 byte)
319 void av_read_image_line2(void *dst, const uint8_t *data[4],
320 const int linesize[4], const AVPixFmtDescriptor *desc,
321 int x, int y, int c, int w, int read_pal_component,
322 int dst_element_size);
324 void av_read_image_line(uint16_t *dst, const uint8_t *data[4],
325 const int linesize[4], const AVPixFmtDescriptor *desc,
326 int x, int y, int c, int w, int read_pal_component);
329 * Write the values from src to the pixel format component c of an
332 * @param src array containing the values to write
333 * @param data the array containing the pointers to the planes of the
334 * image to write into. It is supposed to be zeroed.
335 * @param linesize the array containing the linesizes of the image
336 * @param desc the pixel format descriptor for the image
337 * @param x the horizontal coordinate of the first pixel to write
338 * @param y the vertical coordinate of the first pixel to write
339 * @param w the width of the line to write, that is the number of
340 * values to write to the image line
341 * @param src_element_size size of elements in src array (2 or 4 byte)
343 void av_write_image_line2(const void *src, uint8_t *data[4],
344 const int linesize[4], const AVPixFmtDescriptor *desc,
345 int x, int y, int c, int w, int src_element_size);
347 void av_write_image_line(const uint16_t *src, uint8_t *data[4],
348 const int linesize[4], const AVPixFmtDescriptor *desc,
349 int x, int y, int c, int w);
352 * Utility function to swap the endianness of a pixel format.
354 * @param[in] pix_fmt the pixel format
356 * @return pixel format with swapped endianness if it exists,
357 * otherwise AV_PIX_FMT_NONE
359 enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);
361 #define FF_LOSS_RESOLUTION 0x0001 /**< loss due to resolution change */
362 #define FF_LOSS_DEPTH 0x0002 /**< loss due to color depth change */
363 #define FF_LOSS_COLORSPACE 0x0004 /**< loss due to color space conversion */
364 #define FF_LOSS_ALPHA 0x0008 /**< loss of alpha bits */
365 #define FF_LOSS_COLORQUANT 0x0010 /**< loss due to color quantization */
366 #define FF_LOSS_CHROMA 0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
369 * Compute what kind of losses will occur when converting from one specific
370 * pixel format to another.
371 * When converting from one pixel format to another, information loss may occur.
372 * For example, when converting from RGB24 to GRAY, the color information will
373 * be lost. Similarly, other losses occur when converting from some formats to
374 * other formats. These losses can involve loss of chroma, but also loss of
375 * resolution, loss of color depth, loss due to the color space conversion, loss
376 * of the alpha bits or loss due to color quantization.
377 * av_get_fix_fmt_loss() informs you about the various types of losses
378 * which will occur when converting from one pixel format to another.
380 * @param[in] dst_pix_fmt destination pixel format
381 * @param[in] src_pix_fmt source pixel format
382 * @param[in] has_alpha Whether the source pixel format alpha channel is used.
383 * @return Combination of flags informing you what kind of losses will occur
384 * (maximum loss for an invalid dst_pix_fmt).
386 int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
387 enum AVPixelFormat src_pix_fmt,
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 enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
409 enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);
411 #endif /* AVUTIL_PIXDESC_H */