midi

开发平台：
Unix_Linux

scale.c：源码内容
							/*****************************************************************************
 * resize.c: video scaling module for YUVP/A, I420 and RGBA pictures
 *  Uses the low quality "nearest neighbour" algorithm.
 *****************************************************************************
 * Copyright (C) 2003-2007 the VideoLAN team
 * $Id: 159bd180fca315d1f9889bf6db0b74c9fcd80b1a $
 *
 * Authors: Gildas Bazin <gbazin@videolan.org>
 *          Antoine Cellerier <dionoea @t videolan dot 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.
 *****************************************************************************/
/*****************************************************************************
 * Preamble
 *****************************************************************************/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include <vlc_common.h>
#include <vlc_plugin.h>
#include <vlc_vout.h>
#include "vlc_filter.h"
/*****************************************************************************
 * filter_sys_t : filter descriptor
 *****************************************************************************/
struct filter_sys_t
{
    es_format_t fmt_in;
    es_format_t fmt_out;
};
/****************************************************************************
 * Local prototypes
 ****************************************************************************/
static int  OpenFilter ( vlc_object_t * );
static void CloseFilter( vlc_object_t * );
static picture_t *Filter( filter_t *, picture_t * );
/*****************************************************************************
 * Module descriptor
 *****************************************************************************/
vlc_module_begin ()
    set_description( N_("Video scaling filter") )
    set_capability( "video filter2", 10 )
    set_callbacks( OpenFilter, CloseFilter )
vlc_module_end ()
/*****************************************************************************
 * OpenFilter: probe the filter and return score
 *****************************************************************************/
static int OpenFilter( vlc_object_t *p_this )
{
    filter_t *p_filter = (filter_t*)p_this;
    filter_sys_t *p_sys;
    if( ( p_filter->fmt_in.video.i_chroma != VLC_FOURCC('Y','U','V','P') &&
          p_filter->fmt_in.video.i_chroma != VLC_FOURCC('Y','U','V','A') &&
          p_filter->fmt_in.video.i_chroma != VLC_FOURCC('I','4','2','0') &&
          p_filter->fmt_in.video.i_chroma != VLC_FOURCC('Y','V','1','2') &&
          p_filter->fmt_in.video.i_chroma != VLC_FOURCC('R','V','3','2') &&
          p_filter->fmt_in.video.i_chroma != VLC_FOURCC('R','G','B','A') ) ||
        p_filter->fmt_in.video.i_chroma != p_filter->fmt_out.video.i_chroma )
    {
        return VLC_EGENERIC;
    }
    /* Allocate the memory needed to store the decoder's structure */
    if( ( p_filter->p_sys = p_sys =
          (filter_sys_t *)malloc(sizeof(filter_sys_t)) ) == NULL )
        return VLC_ENOMEM;
    p_filter->pf_video_filter = Filter;
    msg_Dbg( p_filter, "%ix%i -> %ix%i", p_filter->fmt_in.video.i_width,
             p_filter->fmt_in.video.i_height, p_filter->fmt_out.video.i_width,
             p_filter->fmt_out.video.i_height );
    return VLC_SUCCESS;
}
/*****************************************************************************
 * CloseFilter: clean up the filter
 *****************************************************************************/
static void CloseFilter( vlc_object_t *p_this )
{
    filter_t *p_filter = (filter_t*)p_this;
    filter_sys_t *p_sys = p_filter->p_sys;
    free( p_sys );
}
/****************************************************************************
 * Filter: the whole thing
 ****************************************************************************/
static picture_t *Filter( filter_t *p_filter, picture_t *p_pic )
{
    picture_t *p_pic_dst;
    int i_plane;
    if( !p_pic ) return NULL;
    if( (p_filter->fmt_in.video.i_height == 0) ||
        (p_filter->fmt_in.video.i_width == 0) )
        return NULL;
    if( (p_filter->fmt_out.video.i_height == 0) ||
        (p_filter->fmt_out.video.i_width == 0) )
        return NULL;
    /* Request output picture */
    p_pic_dst = filter_NewPicture( p_filter );
    if( !p_pic_dst )
    {
        picture_Release( p_pic );
        return NULL;
    }
    if( p_filter->fmt_in.video.i_chroma != VLC_FOURCC('R','G','B','A') &&
        p_filter->fmt_in.video.i_chroma != VLC_FOURCC('R','V','3','2') )
    {
        for( i_plane = 0; i_plane < p_pic_dst->i_planes; i_plane++ )
        {
            const int i_src_pitch    = p_pic->p[i_plane].i_pitch;
            const int i_dst_pitch    = p_pic_dst->p[i_plane].i_pitch;
            const int i_src_height   = p_filter->fmt_in.video.i_height;
            const int i_src_width    = p_filter->fmt_in.video.i_width;
            const int i_dst_height   = p_filter->fmt_out.video.i_height;
            const int i_dst_width    = p_filter->fmt_out.video.i_width;
            const int i_dst_visible_lines =
                                       p_pic_dst->p[i_plane].i_visible_lines;
            const int i_dst_visible_pitch =
                                       p_pic_dst->p[i_plane].i_visible_pitch;
            const int i_dst_hidden_pitch  = i_dst_pitch - i_dst_visible_pitch;
#define SHIFT_SIZE 16
            const int i_height_coef  = ( i_src_height << SHIFT_SIZE )
                                       / i_dst_height;
            const int i_width_coef   = ( i_src_width << SHIFT_SIZE )
                                       / i_dst_width;
            const int i_src_height_1 = i_src_height - 1;
            const int i_src_width_1  = i_src_width - 1;
            uint8_t *p_src = p_pic->p[i_plane].p_pixels;
            uint8_t *p_dst = p_pic_dst->p[i_plane].p_pixels;
            uint8_t *p_dstendline = p_dst + i_dst_visible_pitch;
            const uint8_t *p_dstend = p_dst + i_dst_visible_lines*i_dst_pitch;
            const int i_shift_height = i_dst_height / i_src_height;
            const int i_shift_width = i_dst_width / i_src_width;
            int l = 1<<(SHIFT_SIZE-i_shift_height);
            for( ; p_dst < p_dstend;
                 p_dst += i_dst_hidden_pitch,
                 p_dstendline += i_dst_pitch, l += i_height_coef )
            {
                int k = 1<<(SHIFT_SIZE-i_shift_width);
                uint8_t *p_srcl = p_src
                       + (__MIN( i_src_height_1, l >> SHIFT_SIZE )*i_src_pitch);
                for( ; p_dst < p_dstendline; p_dst++, k += i_width_coef )
                {
                    *p_dst = p_srcl[__MIN( i_src_width_1, k >> SHIFT_SIZE )];
                }
            }
        }
    }
    else /* RGBA */
    {
        const int i_src_pitch = p_pic->p->i_pitch;
        const int i_dst_pitch = p_pic_dst->p->i_pitch;
        const int i_src_height   = p_filter->fmt_in.video.i_height;
        const int i_src_width    = p_filter->fmt_in.video.i_width;
        const int i_dst_height   = p_filter->fmt_out.video.i_height;
        const int i_dst_width    = p_filter->fmt_out.video.i_width;
        const int i_dst_visible_lines =
                                   p_pic_dst->p->i_visible_lines;
        const int i_dst_visible_pitch =
                                   p_pic_dst->p->i_visible_pitch;
        const int i_dst_hidden_pitch  = i_dst_pitch - i_dst_visible_pitch;
        const int i_height_coef  = ( i_src_height << SHIFT_SIZE )
                                   / i_dst_height;
        const int i_width_coef   = ( i_src_width << SHIFT_SIZE )
                                   / i_dst_width;
        const int i_src_height_1 = i_src_height - 1;
        const int i_src_width_1  = i_src_width - 1;
        uint32_t *p_src = (uint32_t*)p_pic->p->p_pixels;
        uint32_t *p_dst = (uint32_t*)p_pic_dst->p->p_pixels;
        uint32_t *p_dstendline = p_dst + (i_dst_visible_pitch>>2);
        const uint32_t *p_dstend = p_dst + i_dst_visible_lines*(i_dst_pitch>>2);
        const int i_shift_height = i_dst_height / i_src_height;
        const int i_shift_width = i_dst_width / i_src_width;
        int l = 1<<(SHIFT_SIZE-i_shift_height);
        for( ; p_dst < p_dstend;
             p_dst += (i_dst_hidden_pitch>>2),
             p_dstendline += (i_dst_pitch>>2),
             l += i_height_coef )
        {
            int k = 1<<(SHIFT_SIZE-i_shift_width);
            uint32_t *p_srcl = p_src
                    + (__MIN( i_src_height_1, l >> SHIFT_SIZE )*(i_src_pitch>>2));
            for( ; p_dst < p_dstendline; p_dst++, k += i_width_coef )
            {
                *p_dst = p_srcl[__MIN( i_src_width_1, k >> SHIFT_SIZE )];
            }
        }
    }
    picture_CopyProperties( p_pic_dst, p_pic );
    picture_Release( p_pic );
    return p_pic_dst;
}

						