pixdesc.h
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1 /*
2  * pixel format descriptor
3  * Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
4  *
5  * This file is part of FFmpeg.
6  *
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.
11  *
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.
16  *
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
20  */
21 
22 #ifndef AVUTIL_PIXDESC_H
23 #define AVUTIL_PIXDESC_H
24 
25 #include <inttypes.h>
26 #include "pixfmt.h"
27 
28 typedef struct AVComponentDescriptor{
29  uint16_t plane :2; ///< which of the 4 planes contains the component
30 
31  /**
32  * Number of elements between 2 horizontally consecutive pixels minus 1.
33  * Elements are bits for bitstream formats, bytes otherwise.
34  */
35  uint16_t step_minus1 :3;
36 
37  /**
38  * Number of elements before the component of the first pixel plus 1.
39  * Elements are bits for bitstream formats, bytes otherwise.
40  */
41  uint16_t offset_plus1 :3;
42  uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
43  uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
45 
46 /**
47  * Descriptor that unambiguously describes how the bits of a pixel are
48  * stored in the up to 4 data planes of an image. It also stores the
49  * subsampling factors and number of components.
50  *
51  * @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
52  * and all the YUV variants) AVPixFmtDescriptor just stores how values
53  * are stored not what these values represent.
54  */
55 typedef struct AVPixFmtDescriptor{
56  const char *name;
57  uint8_t nb_components; ///< The number of components each pixel has, (1-4)
58 
59  /**
60  * Amount to shift the luma width right to find the chroma width.
61  * For YV12 this is 1 for example.
62  * chroma_width = -((-luma_width) >> log2_chroma_w)
63  * The note above is needed to ensure rounding up.
64  * This value only refers to the chroma components.
65  */
66  uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
67 
68  /**
69  * Amount to shift the luma height right to find the chroma height.
70  * For YV12 this is 1 for example.
71  * chroma_height= -((-luma_height) >> log2_chroma_h)
72  * The note above is needed to ensure rounding up.
73  * This value only refers to the chroma components.
74  */
77 
78  /**
79  * Parameters that describe how pixels are packed.
80  * If the format has 2 or 4 components, then alpha is last.
81  * If the format has 1 or 2 components, then luma is 0.
82  * If the format has 3 or 4 components,
83  * if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
84  * otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
85  */
88 
89 #define PIX_FMT_BE 1 ///< Pixel format is big-endian.
90 #define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
91 #define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
92 #define PIX_FMT_HWACCEL 8 ///< Pixel format is an HW accelerated format.
93 #define PIX_FMT_PLANAR 16 ///< At least one pixel component is not in the first data plane
94 #define PIX_FMT_RGB 32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale)
95 /**
96  * The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
97  * paletted internally, but the palette is generated by the decoder and is not
98  * stored in the file.
99  */
100 #define PIX_FMT_PSEUDOPAL 64
101 
102 #define PIX_FMT_ALPHA 128 ///< The pixel format has an alpha channel
103 
104 
105 #if FF_API_PIX_FMT_DESC
106 /**
107  * The array of all the pixel format descriptors.
108  */
110 #endif
111 
112 /**
113  * Read a line from an image, and write the values of the
114  * pixel format component c to dst.
115  *
116  * @param data the array containing the pointers to the planes of the image
117  * @param linesize the array containing the linesizes of the image
118  * @param desc the pixel format descriptor for the image
119  * @param x the horizontal coordinate of the first pixel to read
120  * @param y the vertical coordinate of the first pixel to read
121  * @param w the width of the line to read, that is the number of
122  * values to write to dst
123  * @param read_pal_component if not zero and the format is a paletted
124  * format writes the values corresponding to the palette
125  * component c in data[1] to dst, rather than the palette indexes in
126  * data[0]. The behavior is undefined if the format is not paletted.
127  */
128 void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4],
129  const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component);
130 
131 /**
132  * Write the values from src to the pixel format component c of an
133  * image line.
134  *
135  * @param src array containing the values to write
136  * @param data the array containing the pointers to the planes of the
137  * image to write into. It is supposed to be zeroed.
138  * @param linesize the array containing the linesizes of the image
139  * @param desc the pixel format descriptor for the image
140  * @param x the horizontal coordinate of the first pixel to write
141  * @param y the vertical coordinate of the first pixel to write
142  * @param w the width of the line to write, that is the number of
143  * values to write to the image line
144  */
145 void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4],
146  const AVPixFmtDescriptor *desc, int x, int y, int c, int w);
147 
148 /**
149  * Return the pixel format corresponding to name.
150  *
151  * If there is no pixel format with name name, then looks for a
152  * pixel format with the name corresponding to the native endian
153  * format of name.
154  * For example in a little-endian system, first looks for "gray16",
155  * then for "gray16le".
156  *
157  * Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
158  */
159 enum AVPixelFormat av_get_pix_fmt(const char *name);
160 
161 /**
162  * Return the short name for a pixel format, NULL in case pix_fmt is
163  * unknown.
164  *
165  * @see av_get_pix_fmt(), av_get_pix_fmt_string()
166  */
167 const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
168 
169 /**
170  * Print in buf the string corresponding to the pixel format with
171  * number pix_fmt, or an header if pix_fmt is negative.
172  *
173  * @param buf the buffer where to write the string
174  * @param buf_size the size of buf
175  * @param pix_fmt the number of the pixel format to print the
176  * corresponding info string, or a negative value to print the
177  * corresponding header.
178  */
179 char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
180 
181 /**
182  * Return the number of bits per pixel used by the pixel format
183  * described by pixdesc.
184  *
185  * The returned number of bits refers to the number of bits actually
186  * used for storing the pixel information, that is padding bits are
187  * not counted.
188  */
189 int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
190 
191 /**
192  * Return the number of bits per pixel for the pixel format
193  * described by pixdesc, including any padding or unused bits.
194  */
196 
197 /**
198  * @return a pixel format descriptor for provided pixel format or NULL if
199  * this pixel format is unknown.
200  */
202 
203 /**
204  * Iterate over all pixel format descriptors known to libavutil.
205  *
206  * @param prev previous descriptor. NULL to get the first descriptor.
207  *
208  * @return next descriptor or NULL after the last descriptor
209  */
211 
212 /**
213  * @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
214  * is not a valid pointer to a pixel format descriptor.
215  */
217 
218 /**
219  * Utility function to access log2_chroma_w log2_chroma_h from
220  * the pixel format AVPixFmtDescriptor.
221  *
222  * See avcodec_get_chroma_sub_sample() for a function that asserts a
223  * valid pixel format instead of returning an error code.
224  * Its recommanded that you use avcodec_get_chroma_sub_sample unless
225  * you do check the return code!
226  *
227  * @param[in] pix_fmt the pixel format
228  * @param[out] h_shift store log2_chroma_w
229  * @param[out] v_shift store log2_chroma_h
230  *
231  * @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
232  */
234  int *h_shift, int *v_shift);
235 
236 /**
237  * @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
238  * valid pixel format.
239  */
241 
242 void ff_check_pixfmt_descriptors(void);
243 
244 #endif /* AVUTIL_PIXDESC_H */
const char * name
Definition: avisynth_c.h:675
void av_read_image_line(uint16_t *dst, const uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w, int read_pal_component)
Read a line from an image, and write the values of the pixel format component c to dst...
Definition: pixdesc.c:32
const AVPixFmtDescriptor av_pix_fmt_descriptors[AV_PIX_FMT_NB]
Definition: pixdesc.c:131
uint8_t log2_chroma_w
Amount to shift the luma width right to find the chroma width.
Definition: pixdesc.h:66
output residual component w
uint16_t shift
number of least significant bits that must be shifted away to get the value
Definition: pixdesc.h:42
int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel used by the pixel format described by pixdesc.
Definition: pixdesc.c:1731
void av_write_image_line(const uint16_t *src, uint8_t *data[4], const int linesize[4], const AVPixFmtDescriptor *desc, int x, int y, int c, int w)
Write the values from src to the pixel format component c of an image line.
Definition: pixdesc.c:80
uint8_t
enum AVPixelFormat pix_fmt
Definition: v4l.c:63
const char * name
Definition: pixdesc.h:56
int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt, int *h_shift, int *v_shift)
Utility function to access log2_chroma_w log2_chroma_h from the pixel format AVPixFmtDescriptor.
Definition: pixdesc.c:1806
Discrete Time axis x
uint16_t depth_minus1
number of bits in the component minus 1
Definition: pixdesc.h:43
uint8_t log2_chroma_h
Amount to shift the luma height right to find the chroma height.
Definition: pixdesc.h:75
Spectrum Plot time data
void ff_check_pixfmt_descriptors(void)
Definition: pixdesc.c:1833
struct AVComponentDescriptor AVComponentDescriptor
uint8_t nb_components
The number of components each pixel has, (1-4)
Definition: pixdesc.h:57
const AVPixFmtDescriptor * av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev)
Iterate over all pixel format descriptors known to libavutil.
Definition: pixdesc.c:1785
const AVPixFmtDescriptor * av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:1778
int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt)
Definition: pixdesc.c:1818
char * av_get_pix_fmt_string(char *buf, int buf_size, enum AVPixelFormat pix_fmt)
Print in buf the string corresponding to the pixel format with number pix_fmt, or an header if pix_fm...
Definition: pixdesc.c:1764
enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc)
Definition: pixdesc.c:1797
AVS_Value src
Definition: avisynth_c.h:523
uint8_t flags
Definition: pixdesc.h:76
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
Definition: pixdesc.h:55
void * buf
Definition: avisynth_c.h:594
struct AVPixFmtDescriptor AVPixFmtDescriptor
Descriptor that unambiguously describes how the bits of a pixel are stored in the up to 4 data planes...
uint16_t step_minus1
Number of elements between 2 horizontally consecutive pixels minus 1.
Definition: pixdesc.h:35
uint16_t plane
which of the 4 planes contains the component
Definition: pixdesc.h:29
static double c[64]
function y
Definition: D.m:1
pixel format definitions
uint16_t offset_plus1
Number of elements before the component of the first pixel plus 1.
Definition: pixdesc.h:41
else dst[i][x+y *dst_stride[i]]
Definition: vf_mcdeint.c:160
const char * av_get_pix_fmt_name(enum AVPixelFormat pix_fmt)
Return the short name for a pixel format, NULL in case pix_fmt is unknown.
Definition: pixdesc.c:1700
int av_get_padded_bits_per_pixel(const AVPixFmtDescriptor *pixdesc)
Return the number of bits per pixel for the pixel format described by pixdesc, including any padding ...
Definition: pixdesc.c:1744
static void comp(unsigned char *dst, int dst_stride, unsigned char *src, int src_stride, int add)
Definition: eamad.c:71
AVPixelFormat
Pixel format.
Definition: pixfmt.h:66
enum AVPixelFormat av_get_pix_fmt(const char *name)
Return the pixel format corresponding to name.
Definition: pixdesc.c:1712