motiondetect.c

VLC Player Source Code

    if( !p_sys->b_old )
    {
        picture_Copy( p_sys->p_old, p_inpic );
        p_sys->b_old = true;
        return p_inpic;
    }

    p_outpic = filter_NewPicture( p_filter );
    if( !p_outpic )
    {
        picture_Release( p_inpic );
        return NULL;
    }
    picture_Copy( p_outpic, p_inpic );

    /* Substract all planes at once */

    for( y = 0; y < p_fmt->i_height; y++ )
    {
        for( x = 0; x < p_fmt->i_width; x+=2 )
        {
            int i;
            int d;

            d = abs( p_inpix[y*i_src_pitch+2*x+i_u_offset] - p_oldpix[y*i_old_pitch+2*x+i_u_offset] ) +
                abs( p_inpix[y*i_src_pitch+2*x+i_v_offset] - p_oldpix[y*i_old_pitch+2*x+i_v_offset] );

            for( i = 0; i < 2; i++ )
                p_buf2[y*p_fmt->i_width+x+i] =
                    abs( p_inpix[y*i_src_pitch+2*(x+i)+i_y_offset] - p_oldpix[y*i_old_pitch+2*(x+i)+i_y_offset] ) + d;
        }
    }

    /**
     * Get the areas where movement was detected
     */
    p_sys->i_colors = FindShapes( p_buf2, p_buf, p_fmt->i_width, p_fmt->i_width, p_fmt->i_height,
                                  p_sys->colors, p_sys->color_x_min, p_sys->color_x_max, p_sys->color_y_min, p_sys->color_y_max );

    /**
     * Count final number of shapes
     * Draw rectangles (there can be more than 1 moving shape in 1 rectangle)
     */
    Draw( p_filter, &p_outpic->p[Y_PLANE].p_pixels[i_y_offset], p_outpic->p[Y_PLANE].i_pitch, 2 );

    /**
     * We're done. Lets keep a copy of the picture
     * TODO we may just picture_Release with a latency of 1 if the filters/vout
     * handle it correctly */
    picture_Copy( p_sys->p_old, p_inpic );

    picture_Release( p_inpic );
    return p_outpic;
}



/*****************************************************************************
 * Gaussian Convolution
 *****************************************************************************
 *    Gaussian convolution ( sigma == 1.4 )
 *
 *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 *    |  5 12 15 12  5  | ~ |  4 12 16 12  4 |
 *    |  4  9 12  9  4  |   |  4  8 12  8  4 |
 *    |  2  4  5  4  2  |   |  2  4  4  4  2 |
 *****************************************************************************/
static void GaussianConvolution( uint32_t *p_inpix, uint32_t *p_smooth,
                                 int i_src_pitch, int i_num_lines,
                                 int i_src_visible )
{
    int x,y;

    /* A bit overkill but ... simpler */
    memset( p_smooth, 0, sizeof(*p_smooth) * i_src_pitch * i_num_lines );

    for( y = 2; y < i_num_lines - 2; y++ )
    {
        for( x = 2; x < i_src_visible - 2; x++ )
        {
            p_smooth[y*i_src_visible+x] = (uint32_t)(
              /* 2 rows up */
                ( p_inpix[(y-2)*i_src_pitch+x-2] )
              + ((p_inpix[(y-2)*i_src_pitch+x-1]
              +   p_inpix[(y-2)*i_src_pitch+x]
              +   p_inpix[(y-2)*i_src_pitch+x+1])<<1 )
              + ( p_inpix[(y-2)*i_src_pitch+x+2] )
              /* 1 row up */
              + ((p_inpix[(y-1)*i_src_pitch+x-2]
              + ( p_inpix[(y-1)*i_src_pitch+x-1]<<1 )
              + ( p_inpix[(y-1)*i_src_pitch+x]*3 )
              + ( p_inpix[(y-1)*i_src_pitch+x+1]<<1 )
              +   p_inpix[(y-1)*i_src_pitch+x+2]
              /* */
              +   p_inpix[y*i_src_pitch+x-2]
              + ( p_inpix[y*i_src_pitch+x-1]*3 )
              + ( p_inpix[y*i_src_pitch+x]<<2 )
              + ( p_inpix[y*i_src_pitch+x+1]*3 )
              +   p_inpix[y*i_src_pitch+x+2]
              /* 1 row down */
              +   p_inpix[(y+1)*i_src_pitch+x-2]
              + ( p_inpix[(y+1)*i_src_pitch+x-1]<<1 )
              + ( p_inpix[(y+1)*i_src_pitch+x]*3 )
              + ( p_inpix[(y+1)*i_src_pitch+x+1]<<1 )
              +   p_inpix[(y+1)*i_src_pitch+x+2] )<<1 )
              /* 2 rows down */
              + ( p_inpix[(y+2)*i_src_pitch+x-2] )
              + ((p_inpix[(y+2)*i_src_pitch+x-1]
              +   p_inpix[(y+2)*i_src_pitch+x]
              +   p_inpix[(y+2)*i_src_pitch+x+1])<<1 )
              + ( p_inpix[(y+2)*i_src_pitch+x+2] )
              ) >> 6 /* 115 */;
        }
    }
}

/*****************************************************************************
 *
 *****************************************************************************/
static int FindShapes( uint32_t *p_diff, uint32_t *p_smooth,
                       int i_pitch, int i_visible, int i_lines,
                       int *colors,
                       int *color_x_min, int *color_x_max,
                       int *color_y_min, int *color_y_max )
{
    int last = 1;
    int i, j;

    /**
     * Apply some smoothing to remove noise
     */
    GaussianConvolution( p_diff, p_smooth, i_pitch, i_lines, i_visible );

    /**
     * Label the shapes and build the labels dependencies list
     */
    for( j = 0; j < i_pitch; j++ )
    {
        p_smooth[j] = 0;
        p_smooth[(i_lines-1)*i_pitch+j] = 0;
    }
    for( i = 1; i < i_lines-1; i++ )
    {
        p_smooth[i*i_pitch] = 0;
        for( j = 1; j < i_pitch-1; j++ )
        {
            if( p_smooth[i*i_pitch+j] > 15 )
            {
                if( p_smooth[(i-1)*i_pitch+j-1] )
                {
                    p_smooth[i*i_pitch+j] = p_smooth[(i-1)*i_pitch+j-1];
                }
                else if( p_smooth[(i-1)*i_pitch+j] )
                    p_smooth[i*i_pitch+j] = p_smooth[(i-1)*i_pitch+j];
                else if( p_smooth[i*i_pitch+j-1] )
                    p_smooth[i*i_pitch+j] = p_smooth[i*i_pitch+j-1];
                else
                {
                    if( last < NUM_COLORS )
                    {
                        p_smooth[i*i_pitch+j] = last;
                        colors[last] = last;
                        last++;
                    }
                }
                #define CHECK( A ) \
                if( p_smooth[A] && p_smooth[A] != p_smooth[i*i_pitch+j] ) \
                { \
                    if( p_smooth[A] < p_smooth[i*i_pitch+j] ) \
                        colors[p_smooth[i*i_pitch+j]] = p_smooth[A]; \
                    else \
                        colors[p_smooth[A]] = p_smooth[i*i_pitch+j]; \
                }
                CHECK( i*i_pitch+j-1 );
                CHECK( (i-1)*i_pitch+j-1 );
                CHECK( (i-1)*i_pitch+j );
                CHECK( (i-1)*i_pitch+j+1 );
                #undef CHECK
            }
            else
            {
                p_smooth[i*i_pitch+j] = 0;
            }
        }
        p_smooth[i*i_pitch+j] = 0;
    }

    /**
     * Initialise empty rectangle list
     */
    for( i = 1; i < last; i++ )
    {
        color_x_min[i] = -1;
        color_x_max[i] = -1;
        color_y_min[i] = -1;
        color_y_max[i] = -1;
    }

    /**
     * Compute rectangle coordinates
     */
    for( i = 0; i < i_pitch * i_lines; i++ )
    {
        if( p_smooth[i] )
        {
            while( colors[p_smooth[i]] != (int)p_smooth[i] )
                p_smooth[i] = colors[p_smooth[i]];
            if( color_x_min[p_smooth[i]] == -1 )
            {
                color_x_min[p_smooth[i]] =
                color_x_max[p_smooth[i]] = i % i_pitch;
                color_y_min[p_smooth[i]] =
                color_y_max[p_smooth[i]] = i / i_pitch;
            }
            else
            {
                int x = i % i_pitch, y = i / i_pitch;
                if( x < color_x_min[p_smooth[i]] )
                    color_x_min[p_smooth[i]] = x;
                if( x > color_x_max[p_smooth[i]] )
                    color_x_max[p_smooth[i]] = x;
                if( y < color_y_min[p_smooth[i]] )
                    color_y_min[p_smooth[i]] = y;
                if( y > color_y_max[p_smooth[i]] )
                    color_y_max[p_smooth[i]] = y;
            }
        }
    }

    /**
     * Merge overlaping rectangles
     */
    for( i = 1; i < last; i++ )
    {
        if( colors[i] != i ) continue;
        if( color_x_min[i] == -1 ) continue;
        for( j = i+1; j < last; j++ )
        {
            if( colors[j] != j ) continue;
            if( color_x_min[j] == -1 ) continue;
            if( __MAX( color_x_min[i], color_x_min[j] ) < __MIN( color_x_max[i], color_x_max[j] ) &&
                __MAX( color_y_min[i], color_y_min[j] ) < __MIN( color_y_max[i], color_y_max[j] ) )
            {
                color_x_min[i] = __MIN( color_x_min[i], color_x_min[j] );
                color_x_max[i] = __MAX( color_x_max[i], color_x_max[j] );
                color_y_min[i] = __MIN( color_y_min[i], color_y_min[j] );
                color_y_max[i] = __MAX( color_y_max[i], color_y_max[j] );
                color_x_min[j] = -1;
                j = 0;
            }
        }
    }

    return last;
}

static void Draw( filter_t *p_filter, uint8_t *p_pix, int i_pix_pitch, int i_pix_size )
{
    filter_sys_t *p_sys = p_filter->p_sys;
    int i, j;

    for( i = 1, j = 0; i < p_sys->i_colors; i++ )
    {
        int x, y;

        if( p_sys->colors[i] != i )
            continue;

        const int color_x_min = p_sys->color_x_min[i];
        const int color_x_max = p_sys->color_x_max[i];
        const int color_y_min = p_sys->color_y_min[i];
        const int color_y_max = p_sys->color_y_max[i];

        if( color_x_min == -1 )
            continue;
        if( ( color_y_max - color_y_min ) * ( color_x_max - color_x_min ) < 16 )
            continue;

        j++;

        y = color_y_min;
        for( x = color_x_min; x <= color_x_max; x++ )
            p_pix[y*i_pix_pitch+x*i_pix_size] = 0xff;

        y = color_y_max;
        for( x = color_x_min; x <= color_x_max; x++ )
            p_pix[y*i_pix_pitch+x*i_pix_size] = 0xff;

        x = color_x_min;
        for( y = color_y_min; y <= color_y_max; y++ )
            p_pix[y*i_pix_pitch+x*i_pix_size] = 0xff;

        x = color_x_max;
        for( y = color_y_min; y <= color_y_max; y++ )
            p_pix[y*i_pix_pitch+x*i_pix_size] = 0xff;
    }
    msg_Dbg( p_filter, "Counted %d moving shapes.", j );
}