vlc_picture.h

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/*****************************************************************************
 * vlc_picture.h: picture definitions
 *****************************************************************************
 * Copyright (C) 1999 - 2009 the VideoLAN team
 * $Id: b0fe6e4d7ac397c37af6417af73d78de80e6a59c $
 *
 * Authors: Vincent Seguin <seguin@via.ecp.fr>
 *          Samuel Hocevar <sam@via.ecp.fr>
 *          Olivier Aubert <oaubert 47 videolan d07 org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifndef VLC_PICTURE_H
#define VLC_PICTURE_H 1

/**
 * \file
 * This file defines picture structures and functions in vlc
 */

#include <vlc_es.h>

/** Description of a planar graphic field */
typedef struct plane_t
{
    uint8_t *p_pixels;                        /**< Start of the plane's data */

    /* Variables used for fast memcpy operations */
    int i_lines;           /**< Number of lines, including margins */
    int i_pitch;           /**< Number of bytes in a line, including margins */

    /** Size of a macropixel, defaults to 1 */
    int i_pixel_pitch;

    /* Variables used for pictures with margins */
    int i_visible_lines;            /**< How many visible lines are there ? */
    int i_visible_pitch;            /**< How many visible pixels are there ? */

} plane_t;

/**
 * Maximum number of plane for a picture
 */
#define PICTURE_PLANE_MAX (VOUT_MAX_PLANES)

/**
 * A private definition to help overloading picture release
 */
typedef struct picture_release_sys_t picture_release_sys_t;

/**
 * Video picture
 */
struct picture_t
{
    /**
     * The properties of the picture
     */
    video_frame_format_t format;

    void           *p_data_orig;                /**< pointer before memalign */
    plane_t         p[PICTURE_PLANE_MAX];     /**< description of the planes */
    int             i_planes;                /**< number of allocated planes */

    /** \name Picture management properties
     * These properties can be modified using the video output thread API,
     * but should never be written directly */
    /**@{*/
    unsigned        i_refcount;                  /**< link reference counter */
    mtime_t         date;                                  /**< display date */
    bool            b_force;
    /**@}*/

    /** \name Picture dynamic properties
     * Those properties can be changed by the decoder
     * @{
     */
    bool            b_progressive;          /**< is it a progressive frame ? */
    bool            b_top_field_first;             /**< which field is first */
    unsigned int    i_nb_fields;                  /**< # of displayed fields */
    int8_t         *p_q;                           /**< quantification table */
    int             i_qstride;                    /**< quantification stride */
    int             i_qtype;                       /**< quantification style */
    /**@}*/

    /** Private data - the video output plugin might want to put stuff here to
     * keep track of the picture */
    picture_sys_t * p_sys;

    /** This way the picture_Release can be overloaded */
    void (*pf_release)( picture_t * );
    picture_release_sys_t *p_release_sys;

    /** Next picture in a FIFO a pictures */
    struct picture_t *p_next;
};

/**
 * This function will create a new picture.
 * The picture created will implement a default release management compatible
 * with picture_Hold and picture_Release. This default management will release
 * p_sys, p_q, p_data_orig fields if non NULL.
 */
VLC_EXPORT( picture_t *, picture_New, ( vlc_fourcc_t i_chroma, int i_width, int i_height, int i_sar_num, int i_sar_den ) LIBVLC_USED );

/**
 * This function will create a new picture using the given format.
 *
 * When possible, it is preferred to use this function over picture_New
 * as more information about the format is kept.
 */
VLC_EXPORT( picture_t *, picture_NewFromFormat, ( const video_format_t *p_fmt ) LIBVLC_USED );

/**
 * Resource for a picture.
 */
typedef struct
{
    picture_sys_t *p_sys;

    /* Plane resources
     * XXX all fields MUST be set to the right value.
     */
    struct
    {
        uint8_t *p_pixels;  /**< Start of the plane's data */
        int i_lines;        /**< Number of lines, including margins */
        int i_pitch;        /**< Number of bytes in a line, including margins */
    } p[PICTURE_PLANE_MAX];

} picture_resource_t;

/**
 * This function will create a new picture using the provided resource.
 *
 * If the resource is NULL then a plain picture_NewFromFormat is returned.
 */
VLC_EXPORT( picture_t *, picture_NewFromResource, ( const video_format_t *, const picture_resource_t * ) LIBVLC_USED );

/**
 * This function will force the destruction a picture.
 * The value of the picture reference count should be 0 before entering this
 * function.
 * Unless used for reimplementing pf_release, you should not use this
 * function but picture_Release.
 */
VLC_EXPORT( void, picture_Delete, ( picture_t * ) );

/**
 * This function will increase the picture reference count.
 * It will not have any effect on picture obtained from vout
 *
 * It returns the given picture for convenience.
 */
static inline picture_t *picture_Hold( picture_t *p_picture )
{
    if( p_picture->pf_release )
        p_picture->i_refcount++;
    return p_picture;
}
/**
 * This function will release a picture.
 * It will not have any effect on picture obtained from vout
 */
static inline void picture_Release( picture_t *p_picture )
{
    /* FIXME why do we let pf_release handle the i_refcount ? */
    if( p_picture->pf_release )
        p_picture->pf_release( p_picture );
}

/**
 * This function will return true if you are not the only owner of the
 * picture.
 *
 * It is only valid if it is created using picture_New.
 */
static inline bool picture_IsReferenced( picture_t *p_picture )
{
    return p_picture->i_refcount > 1;
}

/**
 * Cleanup quantization matrix data and set to 0
 */
static inline void picture_CleanupQuant( picture_t *p_pic )
{
    free( p_pic->p_q );
    p_pic->p_q = NULL;
    p_pic->i_qstride = 0;
    p_pic->i_qtype = 0;
}

/**
 * This function will copy all picture dynamic properties.
 */
static inline void picture_CopyProperties( picture_t *p_dst, const picture_t *p_src )
{
    p_dst->date = p_src->date;
    p_dst->b_force = p_src->b_force;

    p_dst->b_progressive = p_src->b_progressive;
    p_dst->i_nb_fields = p_src->i_nb_fields;
    p_dst->b_top_field_first = p_src->b_top_field_first;

    /* FIXME: copy ->p_q and ->p_qstride */
}

/**
 * This function will reset a picture information (properties and quantizers).
 * It is sometimes useful for reusing pictures (like from a pool).
 */
VLC_EXPORT( void, picture_Reset, ( picture_t * ) );

/**
 * This function will copy the picture pixels.
 * You can safely copy between pictures that do not have the same size,
 * only the compatible(smaller) part will be copied.
 */
VLC_EXPORT( void, picture_CopyPixels, ( picture_t *p_dst, const picture_t *p_src ) );
VLC_EXPORT( void, plane_CopyPixels, ( plane_t *p_dst, const plane_t *p_src ) );

/**
 * This function will copy both picture dynamic properties and pixels.
 * You have to notice that sometime a simple picture_Hold may do what
 * you want without the copy overhead.
 * Provided for convenience.
 *
 * \param p_dst pointer to the destination picture.
 * \param p_src pointer to the source picture.
 */
static inline void picture_Copy( picture_t *p_dst, const picture_t *p_src )
{
    picture_CopyPixels( p_dst, p_src );
    picture_CopyProperties( p_dst, p_src );
}

/**
 * This function will export a picture to an encoded bitstream.
 *
 * pp_image will contain the encoded bitstream in psz_format format.
 *
 * p_fmt can be NULL otherwise it will be set with the format used for the
 * picture before encoding.
 *
 * i_override_width/height allow to override the width and/or the height of the
 * picture to be encoded:
 *  - if strictly lower than 0, the original dimension will be used.
 *  - if equal to 0, it will be deduced from the other dimension which must be
 *  different to 0.
 *  - if strictly higher than 0, it will override the dimension.
 * If at most one of them is > 0 then the picture aspect ratio will be kept.
 */
VLC_EXPORT( int, picture_Export, ( vlc_object_t *p_obj, block_t **pp_image, video_format_t *p_fmt, picture_t *p_picture, vlc_fourcc_t i_format, int i_override_width, int i_override_height ) );

/**
 * This function will setup all fields of a picture_t without allocating any
 * memory.
 * XXX The memory must already be initialized.
 * It does not need to be released.
 *
 * It will return VLC_EGENERIC if the core does not understand the requested
 * format.
 *
 * It can be useful to get the properties of planes.
 */
VLC_EXPORT( int, picture_Setup, ( picture_t *, vlc_fourcc_t i_chroma, int i_width, int i_height, int i_sar_num, int i_sar_den ) );

/*****************************************************************************
 * Flags used to describe the status of a picture
 *****************************************************************************/

/* Quantification type */
enum
{
    QTYPE_NONE,

    QTYPE_MPEG1,
    QTYPE_MPEG2,
    QTYPE_H264,
};

/*****************************************************************************
 * Shortcuts to access image components
 *****************************************************************************/

/* Plane indices */
enum
{
    Y_PLANE = 0,
    U_PLANE = 1,
    V_PLANE = 2,
    A_PLANE = 3,
};

/* Shortcuts */
#define Y_PIXELS     p[Y_PLANE].p_pixels
#define Y_PITCH      p[Y_PLANE].i_pitch
#define U_PIXELS     p[U_PLANE].p_pixels
#define U_PITCH      p[U_PLANE].i_pitch
#define V_PIXELS     p[V_PLANE].p_pixels
#define V_PITCH      p[V_PLANE].i_pitch
#define A_PIXELS     p[A_PLANE].p_pixels
#define A_PITCH      p[A_PLANE].i_pitch

/**@}*/

#endif /* VLC_PICTURE_H */