duckstation

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 */