tor-browser

pixdesc.h (16165B)

---

/*
* 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 "attributes.h"
#include "pixfmt.h"

typedef struct AVComponentDescriptor {
   /**
    * Which of the 4 planes contains the component.
    */
   int plane;

   /**
    * Number of elements between 2 horizontally consecutive pixels.
    * Elements are bits for bitstream formats, bytes otherwise.
    */
   int step;

   /**
    * Number of elements before the component of the first pixel.
    * Elements are bits for bitstream formats, bytes otherwise.
    */
   int offset;

   /**
    * Number of least significant bits that must be shifted away
    * to get the value.
    */
   int shift;

   /**
    * Number of bits in the component.
    */
   int depth;
} 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 = AV_CEIL_RSHIFT(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;

   /**
    * Amount to shift the luma height right to find the chroma height.
    * For YV12 this is 1 for example.
    * chroma_height= AV_CEIL_RSHIFT(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;

   /**
    * Combination of AV_PIX_FMT_FLAG_... flags.
    */
   uint64_t flags;

   /**
    * Parameters that describe how pixels are packed.
    * 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.
    *
    * If present, the Alpha channel is always the last component.
    */
   AVComponentDescriptor comp[4];

   /**
    * Alternative comma-separated names.
    */
   const char *alias;
} AVPixFmtDescriptor;

/**
* Pixel format is big-endian.
*/
#define AV_PIX_FMT_FLAG_BE           (1 << 0)
/**
* Pixel format has a palette in data[1], values are indexes in this palette.
*/
#define AV_PIX_FMT_FLAG_PAL          (1 << 1)
/**
* All values of a component are bit-wise packed end to end.
*/
#define AV_PIX_FMT_FLAG_BITSTREAM    (1 << 2)
/**
* Pixel format is an HW accelerated format.
*/
#define AV_PIX_FMT_FLAG_HWACCEL      (1 << 3)
/**
* At least one pixel component is not in the first data plane.
*/
#define AV_PIX_FMT_FLAG_PLANAR       (1 << 4)
/**
* The pixel format contains RGB-like data (as opposed to YUV/grayscale).
*/
#define AV_PIX_FMT_FLAG_RGB          (1 << 5)

/**
* The pixel format has an alpha channel. This is set on all formats that
* support alpha in some way, including AV_PIX_FMT_PAL8. The alpha is always
* straight, never pre-multiplied.
*
* If a codec or a filter does not support alpha, it should set all alpha to
* opaque, or use the equivalent pixel formats without alpha component, e.g.
* AV_PIX_FMT_RGB0 (or AV_PIX_FMT_RGB24 etc.) instead of AV_PIX_FMT_RGBA.
*/
#define AV_PIX_FMT_FLAG_ALPHA        (1 << 7)

/**
* The pixel format is following a Bayer pattern
*/
#define AV_PIX_FMT_FLAG_BAYER        (1 << 8)

/**
* The pixel format contains IEEE-754 floating point values. Precision (double,
* single, or half) should be determined by the pixel size (64, 32, or 16 bits).
*/
#define AV_PIX_FMT_FLAG_FLOAT        (1 << 9)

/**
* The pixel format contains XYZ-like data (as opposed to YUV/RGB/grayscale).
*/
#define AV_PIX_FMT_FLAG_XYZ          (1 << 10)

/**
* Return the number of bits per pixel used by the pixel format
* described by pixdesc. Note that this is not the same as the number
* of bits per sample.
*
* 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 the number of bits per pixel for the pixel format
* described by pixdesc, including any padding or unused bits.
*/
int av_get_padded_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.
*
* @param[in]  pix_fmt the pixel format
* @param[out] h_shift store log2_chroma_w (horizontal/width shift)
* @param[out] v_shift store log2_chroma_h (vertical/height shift)
*
* @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);

/**
* @return number of planes in pix_fmt, a negative AVERROR if pix_fmt is not a
* valid pixel format.
*/
int av_pix_fmt_count_planes(enum AVPixelFormat pix_fmt);

/**
* @return the name for provided color range or NULL if unknown.
*/
const char *av_color_range_name(enum AVColorRange range);

/**
* @return the AVColorRange value for name or an AVError if not found.
*/
int av_color_range_from_name(const char *name);

/**
* @return the name for provided color primaries or NULL if unknown.
*/
const char *av_color_primaries_name(enum AVColorPrimaries primaries);

/**
* @return the AVColorPrimaries value for name or an AVError if not found.
*/
int av_color_primaries_from_name(const char *name);

/**
* @return the name for provided color transfer or NULL if unknown.
*/
const char *av_color_transfer_name(enum AVColorTransferCharacteristic transfer);

/**
* @return the AVColorTransferCharacteristic value for name or an AVError if not found.
*/
int av_color_transfer_from_name(const char *name);

/**
* @return the name for provided color space or NULL if unknown.
*/
const char *av_color_space_name(enum AVColorSpace space);

/**
* @return the AVColorSpace value for name or an AVError if not found.
*/
int av_color_space_from_name(const char *name);

/**
* @return the name for provided chroma location or NULL if unknown.
*/
const char *av_chroma_location_name(enum AVChromaLocation location);

/**
* @return the AVChromaLocation value for name or an AVError if not found.
*/
int av_chroma_location_from_name(const char *name);

/**
* Converts AVChromaLocation to swscale x/y chroma position.
*
* The positions represent the chroma (0,0) position in a coordinates system
* with luma (0,0) representing the origin and luma(1,1) representing 256,256
*
* @param xpos  horizontal chroma sample position
* @param ypos  vertical   chroma sample position
*/
int av_chroma_location_enum_to_pos(int *xpos, int *ypos, enum AVChromaLocation pos);

/**
* Converts swscale x/y chroma position to AVChromaLocation.
*
* The positions represent the chroma (0,0) position in a coordinates system
* with luma (0,0) representing the origin and luma(1,1) representing 256,256
*
* @param xpos  horizontal chroma sample position
* @param ypos  vertical   chroma sample position
*/
enum AVChromaLocation av_chroma_location_pos_to_enum(int xpos, int ypos);

/**
* 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 a 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);

/**
* 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.
* @param dst_element_size size of elements in dst array (2 or 4 byte)
*/
void av_read_image_line2(void *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,
                       int dst_element_size);

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
* @param src_element_size size of elements in src array (2 or 4 byte)
*/
void av_write_image_line2(const void *src, uint8_t *data[4],
                        const int linesize[4], const AVPixFmtDescriptor *desc,
                        int x, int y, int c, int w, int src_element_size);

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);

/**
* Utility function to swap the endianness of a pixel format.
*
* @param[in]  pix_fmt the pixel format
*
* @return pixel format with swapped endianness if it exists,
* otherwise AV_PIX_FMT_NONE
*/
enum AVPixelFormat av_pix_fmt_swap_endianness(enum AVPixelFormat pix_fmt);

#define FF_LOSS_RESOLUTION        0x0001 /**< loss due to resolution change */
#define FF_LOSS_DEPTH             0x0002 /**< loss due to color depth change */
#define FF_LOSS_COLORSPACE        0x0004 /**< loss due to color space conversion */
#define FF_LOSS_ALPHA             0x0008 /**< loss of alpha bits */
#define FF_LOSS_COLORQUANT        0x0010 /**< loss due to color quantization */
#define FF_LOSS_CHROMA            0x0020 /**< loss of chroma (e.g. RGB to gray conversion) */
#define FF_LOSS_EXCESS_RESOLUTION 0x0040 /**< loss due to unneeded extra resolution */
#define FF_LOSS_EXCESS_DEPTH      0x0080 /**< loss due to unneeded extra color depth */


/**
* Compute what kind of losses will occur when converting from one specific
* pixel format to another.
* When converting from one pixel format to another, information loss may occur.
* For example, when converting from RGB24 to GRAY, the color information will
* be lost. Similarly, other losses occur when converting from some formats to
* other formats. These losses can involve loss of chroma, but also loss of
* resolution, loss of color depth, loss due to the color space conversion, loss
* of the alpha bits or loss due to color quantization.
* av_get_fix_fmt_loss() informs you about the various types of losses
* which will occur when converting from one pixel format to another.
*
* @param[in] dst_pix_fmt destination pixel format
* @param[in] src_pix_fmt source pixel format
* @param[in] has_alpha Whether the source pixel format alpha channel is used.
* @return Combination of flags informing you what kind of losses will occur
* (maximum loss for an invalid dst_pix_fmt).
*/
int av_get_pix_fmt_loss(enum AVPixelFormat dst_pix_fmt,
                       enum AVPixelFormat src_pix_fmt,
                       int has_alpha);

/**
* Compute what kind of losses will occur when converting from one specific
* pixel format to another.
* When converting from one pixel format to another, information loss may occur.
* For example, when converting from RGB24 to GRAY, the color information will
* be lost. Similarly, other losses occur when converting from some formats to
* other formats. These losses can involve loss of chroma, but also loss of
* resolution, loss of color depth, loss due to the color space conversion, loss
* of the alpha bits or loss due to color quantization.
* av_get_fix_fmt_loss() informs you about the various types of losses
* which will occur when converting from one pixel format to another.
*
* @param[in] dst_pix_fmt destination pixel format
* @param[in] src_pix_fmt source pixel format
* @param[in] has_alpha Whether the source pixel format alpha channel is used.
* @return Combination of flags informing you what kind of losses will occur
* (maximum loss for an invalid dst_pix_fmt).
*/
enum AVPixelFormat av_find_best_pix_fmt_of_2(enum AVPixelFormat dst_pix_fmt1, enum AVPixelFormat dst_pix_fmt2,
                                            enum AVPixelFormat src_pix_fmt, int has_alpha, int *loss_ptr);

#endif /* AVUTIL_PIXDESC_H */