PeerStreamer

/*

 * 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>

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 chroma components, they must be stored in comp[1] and

     * comp[2].

     */

    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.

/**

 * The array of all the pixel format descriptors.

 */

extern const AVPixFmtDescriptor av_pix_fmt_descriptors[];

/**

 * 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 PIX_FMT_NONE.

 */

enum PixelFormat av_get_pix_fmt(const char *name);

/**

 * 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);

#endif /* AVUTIL_PIXDESC_H */