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/*
* pixel format descriptor
* Copyright (c) 2009 Michael Niedermayer <michaelni@gmx.at>
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVUTIL_PIXDESC_H
#define AVUTIL_PIXDESC_H
#include <inttypes.h>
#include "pixfmt.h"
typedef struct AVComponentDescriptor{
uint16_t plane :2; ///< which of the 4 planes contains the component
/**
* Number of elements between 2 horizontally consecutive pixels minus 1.
* Elements are bits for bitstream formats, bytes otherwise.
*/
uint16_t step_minus1 :3;
/**
* Number of elements before the component of the first pixel plus 1.
* Elements are bits for bitstream formats, bytes otherwise.
*/
uint16_t offset_plus1 :3;
uint16_t shift :3; ///< number of least significant bits that must be shifted away to get the value
uint16_t depth_minus1 :4; ///< number of bits in the component minus 1
}AVComponentDescriptor;
/**
* Descriptor that unambiguously describes how the bits of a pixel are
* stored in the up to 4 data planes of an image. It also stores the
* subsampling factors and number of components.
*
* @note This is separate of the colorspace (RGB, YCbCr, YPbPr, JPEG-style YUV
* and all the YUV variants) AVPixFmtDescriptor just stores how values
* are stored not what these values represent.
*/
typedef struct AVPixFmtDescriptor{
const char *name;
uint8_t nb_components; ///< The number of components each pixel has, (1-4)
/**
* Amount to shift the luma width right to find the chroma width.
* For YV12 this is 1 for example.
* chroma_width = -((-luma_width) >> log2_chroma_w)
* The note above is needed to ensure rounding up.
* This value only refers to the chroma components.
*/
uint8_t log2_chroma_w; ///< chroma_width = -((-luma_width )>>log2_chroma_w)
/**
* Amount to shift the luma height right to find the chroma height.
* For YV12 this is 1 for example.
* chroma_height= -((-luma_height) >> log2_chroma_h)
* The note above is needed to ensure rounding up.
* This value only refers to the chroma components.
*/
uint8_t log2_chroma_h;
uint8_t flags;
/**
* Parameters that describe how pixels are packed.
* If the format has 2 or 4 components, then alpha is last.
* If the format has 1 or 2 components, then luma is 0.
* If the format has 3 or 4 components,
* if the RGB flag is set then 0 is red, 1 is green and 2 is blue;
* otherwise 0 is luma, 1 is chroma-U and 2 is chroma-V.
*/
AVComponentDescriptor comp[4];
}AVPixFmtDescriptor;
#define PIX_FMT_BE 1 ///< Pixel format is big-endian.
#define PIX_FMT_PAL 2 ///< Pixel format has a palette in data[1], values are indexes in this palette.
#define PIX_FMT_BITSTREAM 4 ///< All values of a component are bit-wise packed end to end.
#define PIX_FMT_HWACCEL 8 ///< Pixel format is an HW accelerated format.
#define PIX_FMT_PLANAR 16 ///< At least one pixel component is not in the first data plane
#define PIX_FMT_RGB 32 ///< The pixel format contains RGB-like data (as opposed to YUV/grayscale)
/**
* The pixel format is "pseudo-paletted". This means that FFmpeg treats it as
* paletted internally, but the palette is generated by the decoder and is not
* stored in the file.
*/
#define PIX_FMT_PSEUDOPAL 64
#define PIX_FMT_ALPHA 128 ///< The pixel format has an alpha channel
#if FF_API_PIX_FMT_DESC
/**
* The array of all the pixel format descriptors.
*/
extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];
#endif
/**
* Read a line from an image, and write the values of the
* pixel format component c to dst.
*
* @param data the array containing the pointers to the planes of the image
* @param linesize the array containing the linesizes of the image
* @param desc the pixel format descriptor for the image
* @param x the horizontal coordinate of the first pixel to read
* @param y the vertical coordinate of the first pixel to read
* @param w the width of the line to read, that is the number of
* values to write to dst
* @param read_pal_component if not zero and the format is a paletted
* format writes the values corresponding to the palette
* component c in data[1] to dst, rather than the palette indexes in
* data[0]. The behavior is undefined if the format is not paletted.
*/
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);
/**
* Write the values from src to the pixel format component c of an
* image line.
*
* @param src array containing the values to write
* @param data the array containing the pointers to the planes of the
* image to write into. It is supposed to be zeroed.
* @param linesize the array containing the linesizes of the image
* @param desc the pixel format descriptor for the image
* @param x the horizontal coordinate of the first pixel to write
* @param y the vertical coordinate of the first pixel to write
* @param w the width of the line to write, that is the number of
* values to write to the image line
*/
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);
/**
* Return the pixel format corresponding to name.
*
* If there is no pixel format with name name, then looks for a
* pixel format with the name corresponding to the native endian
* format of name.
* For example in a little-endian system, first looks for "gray16",
* then for "gray16le".
*
* Finally if no pixel format has been found, returns AV_PIX_FMT_NONE.
*/
enum AVPixelFormat av_get_pix_fmt(const char *name);
/**
* Return the short name for a pixel format, NULL in case pix_fmt is
* unknown.
*
* @see av_get_pix_fmt(), av_get_pix_fmt_string()
*/
const char *av_get_pix_fmt_name(enum AVPixelFormat pix_fmt);
/**
* Print in buf the string corresponding to the pixel format with
* number pix_fmt, or an header if pix_fmt is negative.
*
* @param buf the buffer where to write the string
* @param buf_size the size of buf
* @param pix_fmt the number of the pixel format to print the
* corresponding info string, or a negative value to print the
* corresponding header.
*/
char *av_get_pix_fmt_string (char *buf, int buf_size, enum AVPixelFormat pix_fmt);
/**
* Return the number of bits per pixel used by the pixel format
* described by pixdesc.
*
* The returned number of bits refers to the number of bits actually
* used for storing the pixel information, that is padding bits are
* not counted.
*/
int av_get_bits_per_pixel(const AVPixFmtDescriptor *pixdesc);
/**
* @return a pixel format descriptor for provided pixel format or NULL if
* this pixel format is unknown.
*/
const AVPixFmtDescriptor *av_pix_fmt_desc_get(enum AVPixelFormat pix_fmt);
/**
* Iterate over all pixel format descriptors known to libavutil.
*
* @param prev previous descriptor. NULL to get the first descriptor.
*
* @return next descriptor or NULL after the last descriptor
*/
const AVPixFmtDescriptor *av_pix_fmt_desc_next(const AVPixFmtDescriptor *prev);
/**
* @return an AVPixelFormat id described by desc, or AV_PIX_FMT_NONE if desc
* is not a valid pointer to a pixel format descriptor.
*/
enum AVPixelFormat av_pix_fmt_desc_get_id(const AVPixFmtDescriptor *desc);
/**
* Utility function to access log2_chroma_w log2_chroma_h from
* the pixel format AVPixFmtDescriptor.
*
* See avcodec_get_chroma_sub_sample() for a function that asserts a
* valid pixel format instead of returning an error code.
* Its recommanded that you use avcodec_get_chroma_sub_sample unless
* you do check the return code!
*
* @param[in] pix_fmt the pixel format
* @param[out] h_shift store log2_chroma_h
* @param[out] v_shift store log2_chroma_w
*
* @return 0 on success, AVERROR(ENOSYS) on invalid or unknown pixel format
*/
int av_pix_fmt_get_chroma_sub_sample(enum AVPixelFormat pix_fmt,
int *h_shift, int *v_shift);
#endif /* AVUTIL_PIXDESC_H */
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