composite alpha operations, make obscure alpha aware

[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>
#include <ctype.h>

/** Geometry struct.
*/

struct geometry_s
{
        int nw; // normalised width
        int nh; // normalised height
        int sw; // scaled width, not including consumer scale based upon w/nw
        int sh; // scaled height, not including consumer scale based upon h/nh
        float x;
        float y;
        float w;
        float h;
        float mix;
        int halign; // horizontal alignment: 0=left, 1=center, 2=right
        int valign; // vertical alignment: 0=top, 1=middle, 2=bottom
};

/** 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 = geometry->sw = defaults->w;
                geometry->h = geometry->sh = 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 = geometry->sw = parse_value( &ptr, nw, 'x', geometry->w );
                geometry->h = geometry->sh = 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 + 0.5;
        output->y = in->y + ( out->y - in->y ) * position + 0.5;
        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;
}

/** Parse the alignment properties into the geometry.
*/

static int alignment_parse( char* align )
{
        int ret = 0;
        
        if ( align == NULL );
        else if ( isdigit( align[ 0 ] ) )
                ret = atoi( align );
        else if ( align[ 0 ] == 'c' || align[ 0 ] == 'm' )
                ret = 1;
        else if ( align[ 0 ] == 'r' || align[ 0 ] == 'b' )
                ret = 2;

        return ret;
}

/** Adjust position according to scaled size and alignment properties.
*/

static void alignment_calculate( struct geometry_s *geometry )
{
        geometry->x += ( geometry->w - geometry->sw ) * geometry->halign / 2 + 0.5;
        geometry->y += ( geometry->h - geometry->sh ) * geometry->valign / 2 + 0.5;
}

/** 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 );
}

/** Calculate the field delta for this frame - position between two frames.
*/

static float delta_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
        float x = ( float )( position - in ) / ( float )( out - in + 1 );
        position++;
        float y = ( float )( position - in ) / ( float )( out - in + 1 );

        return ( y - x ) / 2.0;
}

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, int bpp, uint8_t *p_src, int width_src, int height_src, uint8_t *p_alpha, struct geometry_s geometry, int field )
{
        int ret = 0;
        int i, j, k;
        int x_src = 0, y_src = 0;
        float weight = geometry.mix / 100;
        int stride_src = width_src * bpp;
        int stride_dest = width_dest * bpp;

        // Adjust to consumer scale
        int x = geometry.x * width_dest / geometry.nw + 0.5;
        int y = geometry.y * height_dest / geometry.nh + 0.5;

        if ( bpp == 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 * bpp + y_src * stride_src;

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

        // Assuming lower field first
        // Special care is taken to make sure the b_frame is aligned to the correct field.
        // field 0 = lower field and y should be odd (y is 0-based).
        // field 1 = upper field and y should be even.
        if ( ( field > -1 ) && ( y % 2 == field ) )
        {
                if ( y == 0 )
                        p_dest += stride_dest;
                else
                        p_dest -= stride_dest;
        }

        // On the second field, use the other lines from b_frame
        if ( field == 1 )
        {
                p_src += stride_src;
                if ( p_alpha )
                        p_alpha += stride_src / bpp;
                height_src--;
        }

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

        uint8_t a;
        float value;
        int step = ( field > -1 ) ? 2 : 1;

        // now do the compositing only to cropped extents
        for ( i = 0; i < height_src; i += step )
        {
                p = &p_src[ i * stride_src ];
                q = &p_dest[ i * stride_dest ];
                o = &p_dest[ i * stride_dest ];
                if ( p_alpha )
                        z = &p_alpha[ i * stride_src / bpp ];

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

        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;

        // Initialise the scaled dimensions from the computed
        geometry->sw = geometry->w;
        geometry->sh = geometry->h;

        // 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 )
        {
                // Adjust b_frame pixel aspect
                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;
                int scaled_width = real_width;
                int scaled_height = real_height;
                double output_sar = ( double ) geometry->nw / geometry->nh / output_ar;

                // We always normalise pixel aspect by requesting a larger than normal
                // image in order to maximise usage of the bounding rectangle

                // These calcs are optimised by reducing factors in equations
                if ( output_sar < 1.0 )
                        // If the output is skinny pixels (PAL) then stretch our input vertically
                        // derived from: input_sar / output_sar * real_height
                        scaled_height = ( double )real_width / input_ar / output_sar;

                else
                        // If the output is fat pixels (NTSC) then stretch our input horizontally
                        // derived from: output_sar / input_sar * real_width
                        scaled_width = output_sar * real_height * input_ar;
                        
//              fprintf( stderr, "composite: real %dx%d scaled %dx%d normalised %dx%d\n", real_width, real_height, scaled_width, scaled_height, normalised_width, normalised_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;
                }

#if 0
                // DRD> Why?
                // Special case
                if ( scaled_height == normalised_height )
                        scaled_width = normalised_width;
#endif

                // Now we need to align to the geometry
                if ( scaled_width <= geometry->w && scaled_height <= geometry->h )
                {
                        // Save the new scaled dimensions
                        geometry->sw = scaled_width;
                        geometry->sh = scaled_height;
                }
        }

        // We want to ensure that we bypass resize now...
        mlt_properties_set( b_props, "distort", "true" );

        // Take into consideration alignment for optimisation
        alignment_calculate( geometry );

        // Adjust to consumer scale
        int x = geometry->x * *width / geometry->nw + 0.5;
        int y = geometry->y * *height / geometry->nh + 0.5;
        *width = geometry->sw * *width / geometry->nw;
        *height = geometry->sh * *height / geometry->nh;

        x -= x % 2;

        //fprintf( stderr, "composite calculated %d,%d:%dx%d\n", x, y, *width, *height );

        // 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;
}


static uint8_t *transition_get_alpha_mask( mlt_frame this )
{
        // Obtain properties of frame
        mlt_properties properties = mlt_frame_properties( this );

        // Return the alpha mask
        return mlt_properties_get_data( properties, "alpha", NULL );
}

/** 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 );
                float delta = delta_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 );

                // Now parse the alignment
                result.halign = alignment_parse( mlt_properties_get( properties, "halign" ) );
                result.valign = alignment_parse( mlt_properties_get( properties, "valign" ) );

                // 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" ) );

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

                // 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 *dest = *image;
                        uint8_t *src = image_b;
                        int bpp = 2;
                        uint8_t *alpha = mlt_frame_get_alpha_mask( b_frame );
                        int progressive = mlt_properties_get_int( a_props, "progressive" ) ||
                                        mlt_properties_get_int( a_props, "consumer_progressive" ) ||
                                        mlt_properties_get_int( properties, "progressive" );
                        int field;

                        // See if the alpha channel is our destination
                        if ( mlt_properties_get( properties, "a_frame" ) != NULL )
                        {
                                bpp = 1;
                                
                                // Get or make the a_frame alpha channel
                                dest = mlt_frame_get_alpha_mask( a_frame );
                                if ( dest == NULL )
                                {
                                        // Allocate the alpha
                                        dest = mlt_pool_alloc( *width * *height );
                                        mlt_properties_set_data( a_props, "alpha", dest, *width * *height, ( mlt_destructor )mlt_pool_release, NULL );
                                        
                                        // Set alpha call back
                                        a_frame->get_alpha_mask = transition_get_alpha_mask;
                                }

                                // If the source is an image, convert its YUV to an alpha channel
                                if ( mlt_properties_get( properties, "b_frame" ) == NULL )
                                {
                                        if ( alpha == NULL )
                                        {
                                                // Allocate the alpha
                                                alpha = mlt_pool_alloc( width_b * height_b );
                                                mlt_properties_set_data( b_props, "alpha", alpha, width_b * height_b, ( mlt_destructor )mlt_pool_release, NULL );

                                                // Set alpha call back
                                                b_frame->get_alpha_mask = transition_get_alpha_mask;
                                        }

                                        // Copy the Y values into alpha
                                        uint8_t *p = image_b;
                                        uint8_t *q = alpha;
                                        int i;
                                        for ( i = 0; i < width_b * height_b; i ++, p += 2 )
                                                *q ++ = *p;

                                        // Setup to composite from the alpha channel
                                        src = alpha;
                                        alpha = NULL;
                                }
                        }
                        
                        // See if the alpha channel is our source
                        if ( mlt_properties_get( properties, "b_frame" ) != NULL )
                        {
                                // If we do not have an alpha channel fabricate it
                                if ( alpha == NULL )
                                {
                                        // Allocate the alpha
                                        alpha = mlt_pool_alloc( width_b * height_b );
                                        mlt_properties_set_data( b_props, "alpha", alpha, width_b * height_b, ( mlt_destructor )mlt_pool_release, NULL );

                                        // Set alpha call back
                                        b_frame->get_alpha_mask = transition_get_alpha_mask;
                                        
                                        // Copy the Y values into alpha
                                        uint8_t *p = image_b;
                                        uint8_t *q = alpha;
                                        int i;
                                        for ( i = 0; i < width_b * height_b; i ++, p += 2 )
                                                *q ++ = *p;
                                }

                                // If the destination is image, convert the alpha channel to YUV
                                if ( mlt_properties_get( properties, "a_frame" ) == NULL )
                                {
                                        uint8_t *p = alpha;
                                        uint8_t *q = image_b;
                                        int i;
                                        
                                        for ( i = 0; i < width_b * height_b; i ++, p ++ )
                                        {
                                                *q ++ = 16 + ( ( float )*p / 255 * 220 ); // 220 is the luma range from 16-235
                                                *q ++ = 128;
                                        }
                                }
                                else
                                {
                                        // Setup to composite from the alpha channel
                                        src = alpha;
                                        bpp = 1;
                                }

                                // Never the apply the alpha channel to this type of operation
                                alpha = NULL;
                        }

                        for ( field = 0; field < ( progressive ? 1 : 2 ); field++ )
                        {
                                // Assume lower field (0) first
                                float field_position = position + field * delta;
                                
                                // Do the calculation
                                geometry_calculate( &result, &start, &end, field_position );

                                // Align
                                alignment_calculate( &result );

                                // Composite the b_frame on the a_frame
                                composite_yuv( dest, *width, *height, bpp, src, width_b, height_b, alpha, result, progressive ? -1 : field );
                        }
                }
        }

        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;
}