[melted] / src / modules / core / transition_composite.c

/*
 * transition_composite.c -- compose one image over another using alpha channel
 * Copyright (C) 2003-2004 Ushodaya Enterprises Limited
 * Author: Dan Dennedy <dan@dennedy.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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include "transition_composite.h"
#include <framework/mlt_frame.h>

#include <stdio.h>
#include <stdlib.h>

/** Geometry struct.
*/

struct geometry_s
{
        float x;
        float y;
        float w;
        float h;
        float mix;
};

/** Parse a geometry property string.
*/

static void geometry_parse( struct geometry_s *geometry, struct geometry_s *defaults, char *property )
{
        // Assign from defaults if available
        if ( defaults != NULL )
        {
                geometry->x = defaults->x;
                geometry->y = defaults->y;
                geometry->w = defaults->w;
                geometry->h = defaults->h;
                geometry->mix = defaults->mix;
        }
        else
        {
                geometry->mix = 100;
        }

        // Parse the geomtry string
        if ( property != NULL )
                sscanf( property, "%f,%f:%fx%f:%f", &geometry->x, &geometry->y, &geometry->w, &geometry->h, &geometry->mix );
}

/** Calculate real geometry.
*/

static void geometry_calculate( struct geometry_s *output, struct geometry_s *in, struct geometry_s *out, float position )
{
        // Calculate this frames geometry
        output->x = in->x + ( out->x - in->x ) * position;
        output->y = in->y + ( out->y - in->y ) * position;
        output->w = in->w + ( out->w - in->w ) * position;
        output->h = in->h + ( out->h - in->h ) * position;
        output->mix = in->mix + ( out->mix - in->mix ) * position;
}

/** Calculate the position for this frame.
*/

static float position_calculate( mlt_transition this, mlt_frame frame )
{
        // Get the in and out position
        mlt_position in = mlt_transition_get_in( this );
        mlt_position out = mlt_transition_get_out( this );

        // Get the position of the frame
        mlt_position position = mlt_frame_get_position( frame );

        // Now do the calcs
        return ( float )( position - in ) / ( float )( out - in + 1 );
}

/** Composite function.
*/

static int composite_yuv( uint8_t *p_dest, mlt_image_format format_dest, int width_dest, int height_dest, mlt_frame that, struct geometry_s geometry )
{
        int ret = 0;
        uint8_t *p_src;
        int i, j;
        int stride_src;
        int stride_dest;
        int x_src = 0, y_src = 0;

        mlt_image_format format_src = format_dest;
        int x = ( int )( ( float )width_dest * geometry.x / 100 );
        int y = ( int )( ( float )height_dest * geometry.y / 100 );
        float weight = geometry.mix / 100;

        // Compute the dimensioning rectangle
        int width_src = ( int )( ( float )width_dest * geometry.w / 100 );
        int height_src = ( int )( ( float )height_dest * geometry.h / 100 );

        mlt_properties b_props = mlt_frame_properties( that );
        mlt_transition this = mlt_properties_get_data( b_props, "transition_composite", NULL );
        mlt_properties properties = mlt_transition_properties( this );

        if ( mlt_properties_get( properties, "distort" ) == NULL &&
                 mlt_properties_get( mlt_frame_properties( that ), "real_width" ) != NULL )
        {
                int width_b = mlt_properties_get_double( b_props, "real_width" );
                int height_b = mlt_properties_get_double( b_props, "real_height" );

                // See if we need to normalise pixel aspect ratio
                // We can use consumer_aspect_ratio because the a_frame will take on this aspect
                double aspect = mlt_properties_get_double( b_props, "consumer_aspect_ratio" );
                if ( aspect != 0 )
                {
                        // Derive the consumer pixel aspect
                        double oaspect = aspect / ( double )width_dest * height_dest;

                        // Get the b frame pixel aspect - usually 1
                        double iaspect = mlt_properties_get_double( b_props, "aspect_ratio" ) / width_b * height_b;

                        // Normalise pixel aspect
                        if ( iaspect != 0 && iaspect != oaspect )
                                width_b = iaspect / oaspect * ( double )width_b + 0.5;
                                
                        // Tell rescale not to normalise display aspect
                        mlt_frame_set_aspect_ratio( that, aspect );
                }

                // Constrain the overlay to the dimensioning rectangle
                if ( width_b < width_src )
                        width_src = width_b;
                if ( height_b < height_src )
                        height_src = height_b;

                // Adjust overall scale for consumer
                double consumer_scale = mlt_properties_get_double( b_props, "consumer_scale" );
                if ( consumer_scale > 0 )
                {
                        width_src = consumer_scale * width_src + 0.5;
                        height_src = consumer_scale * height_src + 0.5;
                }
        }
        else if ( mlt_properties_get( b_props, "real_width" ) != NULL )
        {
                // Tell rescale not to normalise display aspect
                mlt_properties_set_double( b_props, "consumer_aspect_ratio", 0 );
        }

        x -= x % 2;

        // optimization points - no work to do
        if ( width_src <= 0 || height_src <= 0 )
                return ret;

        if ( ( x < 0 && -x >= width_src ) || ( y < 0 && -y >= height_src ) )
                return ret;

        format_src = mlt_image_yuv422;
        format_dest = mlt_image_yuv422;

        mlt_frame_get_image( that, &p_src, &format_src, &width_src, &height_src, 1 /* writable */ );

        stride_src = width_src * 2;
        stride_dest = width_dest * 2;
        
        // crop overlay off the left edge of frame
        if ( x < 0 )
        {
                x_src = -x;
                width_src -= x_src;
                x = 0;
        }
        
        // crop overlay beyond right edge of frame
        else if ( x + width_src > width_dest )
                width_src = width_dest - x;

        // crop overlay off the top edge of the frame
        if ( y < 0 )
        {
                y_src = -y;
                height_src -= y_src;
        }
        // crop overlay below bottom edge of frame
        else if ( y + height_src > height_dest )
                height_src = height_dest - y;

        // offset pointer into overlay buffer based on cropping
        p_src += x_src * 2 + y_src * stride_src;

        // offset pointer into frame buffer based upon positive, even coordinates only!
        p_dest += ( x < 0 ? 0 : x ) * 2 + ( y < 0 ? 0 : y ) * stride_dest;

        // Get the alpha channel of the overlay
        uint8_t *p_alpha = mlt_frame_get_alpha_mask( that );

        // offset pointer into alpha channel based upon cropping
        if ( p_alpha )
                p_alpha += x_src + y_src * stride_src / 2;

        uint8_t *p = p_src;
        uint8_t *q = p_dest;
        uint8_t *o = p_dest;
        uint8_t *z = p_alpha;

        uint8_t Y;
        uint8_t UV;
        uint8_t a;
        float value;

        // now do the compositing only to cropped extents
        for ( i = 0; i < height_src; i++ )
        {
                p = p_src;
                q = p_dest;
                o = p_dest;
                z = p_alpha;

                for ( j = 0; j < width_src; j ++ )
                {
                        Y = *p ++;
                        UV = *p ++;
                        a = ( z == NULL ) ? 255 : *z ++;
                        value = ( weight * ( float ) a / 255.0 );
                        *o ++ = (uint8_t)( Y * value + *q++ * ( 1 - value ) );
                        *o ++ = (uint8_t)( UV * value + *q++ * ( 1 - value ) );
                }

                p_src += stride_src;
                p_dest += stride_dest;
                if ( p_alpha )
                        p_alpha += stride_src / 2;
        }

        return ret;
}


/** Get the image.
*/

static int transition_get_image( mlt_frame a_frame, uint8_t **image, mlt_image_format *format, int *width, int *height, int writable )
{
        // Get the b frame from the stack
        mlt_frame b_frame = mlt_frame_pop_frame( a_frame );

        // Get the image from the a frame
        mlt_frame_get_image( a_frame, image, format, width, height, 1 );

        if ( b_frame != NULL )
        {
                // Get the properties of the b frame
                mlt_properties b_props = mlt_frame_properties( b_frame );

                // Get the transition from the b frame
                mlt_transition this = mlt_properties_get_data( b_props, "transition_composite", NULL );

                // Get the properties from the transition
                mlt_properties properties = mlt_transition_properties( this );

                // Structures for geometry
                struct geometry_s result;
                struct geometry_s start;
                struct geometry_s end;

                // Calculate the position
                float position = position_calculate( this, a_frame );

                // Now parse the geometries
                geometry_parse( &start, NULL, mlt_properties_get( properties, "start" ) );
                geometry_parse( &end, &start, mlt_properties_get( properties, "end" ) );

                // Do the calculation
                geometry_calculate( &result, &start, &end, position );

                // Since we are the consumer of the b_frame, we must pass along these
                // consumer properties from the a_frame
                mlt_properties_set_double( b_props, "consumer_aspect_ratio",
                        mlt_properties_get_double( mlt_frame_properties( a_frame ), "consumer_aspect_ratio" ) );
                mlt_properties_set_double( b_props, "consumer_scale",
                        mlt_properties_get_double( mlt_frame_properties( a_frame ), "consumer_scale" ) );
                
                // Composite the b_frame on the a_frame
                composite_yuv( *image, *format, *width, *height, b_frame, result );
        }

        return 0;
}

/** Composition transition processing.
*/

static mlt_frame composite_process( mlt_transition this, mlt_frame a_frame, mlt_frame b_frame )
{
        // Propogate the transition properties to the b frame
        mlt_properties b_props = mlt_frame_properties( b_frame );
        mlt_properties_set_data( b_props, "transition_composite", this, 0, NULL, NULL );
        mlt_frame_push_get_image( a_frame, transition_get_image );
        mlt_frame_push_frame( a_frame, b_frame );
        return a_frame;
}

/** Constructor for the filter.
*/

mlt_transition transition_composite_init( char *arg )
{
        mlt_transition this = calloc( sizeof( struct mlt_transition_s ), 1 );
        if ( this != NULL && mlt_transition_init( this, NULL ) == 0 )
        {
                this->process = composite_process;
                mlt_properties_set( mlt_transition_properties( this ), "start", arg != NULL ? arg : "85,5:10x10" );
                mlt_properties_set( mlt_transition_properties( this ), "end", "" );
        }
        return this;
}