int mlt_frame_composite_yuv( mlt_frame this, mlt_frame that, int x, int y, float weight )
{
int ret = 0;
- int x_start = 0;
int width_src, height_src;
int width_dest, height_dest;
mlt_image_format format_src, format_dest;
uint8_t *p_src, *p_dest;
- int x_end;
int i, j;
int stride_src;
int stride_dest;
+ int x_src = 0, y_src = 0;
+
+ // optimization point - no work to do
+ 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( this, &p_dest, &format_dest, &width_dest, &height_dest, 1 /* writable */ );
mlt_frame_get_image( that, &p_src, &format_src, &width_src, &height_src, 0 /* writable */ );
- x_end = width_src;
-
stride_src = width_src * 2;
stride_dest = width_dest * 2;
- uint8_t *lower = p_dest;
- uint8_t *upper = p_dest + height_dest * stride_dest;
-
- p_dest += ( y * stride_dest ) + ( x * 2 );
-
+
+ // crop overlay off the left edge of frame
if ( x < 0 )
{
- x_start = -x;
- x_end += x_start;
+ 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!
+// if ( interlaced && y % 2 )
+// ++y;
+ 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 );
- uint8_t *z = 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;
+ // now do the compositing only to cropped extents
for ( i = 0; i < height_src; i++ )
{
uint8_t *p = p_src;
uint8_t *q = p_dest;
uint8_t *o = p_dest;
+ uint8_t *z = p_alpha;
for ( j = 0; j < width_src; j ++ )
{
- if ( q >= lower && q < upper && j >= x_start && j < x_end )
- {
uint8_t y = *p ++;
uint8_t uv = *p ++;
uint8_t a = ( z == NULL ) ? 255 : *z ++;
float value = ( weight * ( float ) a / 255.0 );
*o ++ = (uint8_t)( y * value + *q++ * ( 1 - value ) );
*o ++ = (uint8_t)( uv * value + *q++ * ( 1 - value ) );
- }
- else
- {
- p += 2;
- o += 2;
- q += 2;
- if ( z != NULL )
- z += 1;
- }
}
p_src += stride_src;
p_dest += stride_dest;
+ if ( p_alpha )
+ p_alpha += stride_src / 2;
}
return ret;