[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
{
        int nw;
        int nh;
        float x;
        float y;
        float w;
        float h;
        float mix;
};

/** Parse a value from a geometry string.
*/

static float parse_value( char **ptr, int normalisation, char delim, float defaults )
{
        float value = defaults;

        if ( *ptr != NULL && **ptr != '\0' )
        {
                char *end = NULL;
                value = strtod( *ptr, &end );
                if ( end != NULL )
                {
                        if ( *end == '%' )
                                value = ( value / 100.0 ) * normalisation;
                        while ( *end == delim || *end == '%' )
                                end ++;
                }
                *ptr = end;
        }

        return value;
}

/** Parse a geometry property string with the syntax X,Y:WxH:MIX. Any value can be 
        expressed as a percentage by appending a % after the value, otherwise values are
        assumed to be relative to the normalised dimensions of the consumer.
*/

static void geometry_parse( struct geometry_s *geometry, struct geometry_s *defaults, char *property, int nw, int nh )
{
        // Assign normalised width and height
        geometry->nw = nw;
        geometry->nh = nh;

        // 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 )
        {
                char *ptr = property;
                geometry->x = parse_value( &ptr, nw, ',', geometry->x );
                geometry->y = parse_value( &ptr, nh, ':', geometry->y );
                geometry->w = parse_value( &ptr, nw, 'x', geometry->w );
                geometry->h = parse_value( &ptr, nh, ':', geometry->h );
                geometry->mix = parse_value( &ptr, 100, ' ', 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->nw = in->nw;
        output->nh = in->nh;
        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 );
}

static int get_value( mlt_properties properties, char *preferred, char *fallback )
{
        int value = mlt_properties_get_int( properties, preferred );
        if ( value == 0 )
                value = mlt_properties_get_int( properties, fallback );
        return value;
}

/** Composite function.
*/

static int composite_yuv( uint8_t *p_dest, int width_dest, int height_dest, uint8_t *p_src, int width_src, int height_src, uint8_t *p_alpha, struct geometry_s geometry )
{
        int ret = 0;
        int i, j;
        int x_src = 0, y_src = 0;
        float weight = geometry.mix / 100;
        int x = ( geometry.x * width_dest ) / geometry.nw;
        int y = ( geometry.y * height_dest ) / geometry.nh;
        int stride_src = width_src * 2;
        int stride_dest = width_dest * 2;

        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;

        // 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;

        // 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 properly sized image from b_frame.
*/

static int get_b_frame_image( mlt_frame b_frame, uint8_t **image, int *width, int *height, struct geometry_s *geometry )
{
        int ret = 0;
        mlt_image_format format = mlt_image_yuv422;

        // Compute the dimensioning rectangle
        mlt_properties b_props = mlt_frame_properties( b_frame );
        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 )
        {
                // Now do additional calcs based on real_width/height etc
                //int normalised_width = mlt_properties_get_int( b_props, "normalised_width" );
                //int normalised_height = mlt_properties_get_int( b_props, "normalised_height" );
                int normalised_width = geometry->w;
                int normalised_height = geometry->h;
                int real_width = get_value( b_props, "real_width", "width" );
                int real_height = get_value( b_props, "real_height", "height" );
                double input_ar = mlt_frame_get_aspect_ratio( b_frame );
                double output_ar = mlt_properties_get_double( b_props, "consumer_aspect_ratio" );
                int scaled_width = ( input_ar > output_ar ? input_ar / output_ar : output_ar / input_ar ) * real_width;
                int scaled_height = ( input_ar > output_ar ? input_ar / output_ar : output_ar / input_ar ) * real_height;

                // Now ensure that our images fit in the normalised frame
                if ( scaled_width > normalised_width )
                {
                        scaled_height = scaled_height * normalised_width / scaled_width;
                        scaled_width = normalised_width;
                }
                if ( scaled_height > normalised_height )
                {
                        scaled_width = scaled_width * normalised_height / scaled_height;
                        scaled_height = normalised_height;
                }

                // Special case
                if ( scaled_height == normalised_height )
                        scaled_width = normalised_width;

                // Now we need to align to the geometry
                if ( scaled_width <= geometry->w && scaled_height <= geometry->h )
                {
                        // TODO: Should take into account requested alignment here...
                        // Assume centred alignment for now

                        geometry->x = geometry->x + ( geometry->w - scaled_width ) / 2;
                        geometry->y = geometry->y + ( geometry->h - scaled_height ) / 2;
                        geometry->w = scaled_width;
                        geometry->h = scaled_height;
                        mlt_properties_set( b_props, "distort", "true" );
                }
                else
                {
                        mlt_properties_set( b_props, "distort", "true" );
                }
        }
        else
        {
                // We want to ensure that we bypass resize now...
                mlt_properties_set( b_props, "distort", "true" );
        }

        int x = ( geometry->x * *width ) / geometry->nw;
        int y = ( geometry->y * *height ) / geometry->nh;
        *width = ( geometry->w * *width ) / geometry->nw;
        *height = ( geometry->h * *height ) / geometry->nh;

        x -= x % 2;

        // optimization points - no work to do
        if ( *width <= 0 || *height <= 0 )
                return 1;

        if ( ( x < 0 && -x >= *width ) || ( y < 0 && -y >= *height ) )
                return 1;

        ret = mlt_frame_get_image( b_frame, image, &format, width, height, 1 /* writable */ );

        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 );

        // This compositer is yuv422 only
        *format = mlt_image_yuv422;

        // 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 a frame
                mlt_properties a_props = mlt_frame_properties( a_frame );

                // 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 );

                // Obtain the normalised width and height from the a_frame
                int normalised_width = mlt_properties_get_int( a_props, "normalised_width" );
                int normalised_height = mlt_properties_get_int( a_props, "normalised_height" );

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

                // 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( a_props, "consumer_aspect_ratio" ) );
                mlt_properties_set_double( b_props, "consumer_scale", mlt_properties_get_double( a_props, "consumer_scale" ) );

                // Get the image from the b frame
                uint8_t *image_b;
                int width_b = *width;
                int height_b = *height;
                if ( get_b_frame_image( b_frame, &image_b, &width_b, &height_b, &result ) == 0 )
                {
                        uint8_t *alpha = mlt_frame_get_alpha_mask( b_frame );
                        
                        // Composite the b_frame on the a_frame
                        composite_yuv( *image, *width, *height, image_b, width_b, height_b, alpha, 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%:10%x10%" );
                mlt_properties_set( mlt_transition_properties( this ), "end", "" );
        }
        return this;
}