gstreamer/gst/dvdspu/gstdvdspu-render.c
Jan Schmidt b68a05dbfa gstspu: Implement PGS rendering and alpha blending
Refactor the DVD subpicture compositing, switching it to 8-bit alpha
calculations. Reuse some of the resulting code to implement PGS
subpicture blending.

Implement parsing and collecting of composition objects properly, but
assuming a single active window and colour palette for now. I need more
PGS samples.
2009-05-26 15:58:09 +01:00

94 lines
2.9 KiB
C

/* GStreamer DVD Sub-Picture Unit
* Copyright (C) 2007 Fluendo S.A. <info@fluendo.com>
* Copyright (C) 2009 Jan Schmidt <thaytan@noraisin.net>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <gst/gst.h>
#include "gstdvdspu.h"
GST_DEBUG_CATEGORY_EXTERN (dvdspu_debug);
#define GST_CAT_DEFAULT dvdspu_debug
void
gstspu_clear_comp_buffers (SpuState * state)
{
/* The area to clear is the line inside the disp_rect, each entry 4 bytes,
* of the sub-sampled UV planes. */
gint16 left = state->comp_left / 2;
gint16 right = state->comp_right / 2;
gint16 uv_width = sizeof (guint32) * (right - left + 1);
memset (state->comp_bufs[0] + left, 0, uv_width);
memset (state->comp_bufs[1] + left, 0, uv_width);
memset (state->comp_bufs[2] + left, 0, uv_width);
}
void
gstspu_blend_comp_buffers (SpuState * state, guint8 * planes[3])
{
gint16 uv_end;
gint16 left, x;
guint8 *out_U;
guint8 *out_V;
guint32 *in_U;
guint32 *in_V;
guint32 *in_A;
gint16 comp_last_x = state->comp_right;
if (comp_last_x < state->comp_left)
return; /* Didn't draw in the comp buffers, nothing to do... */
#if 0
GST_LOG ("Blending comp buffers from x=%d to x=%d",
state->comp_left, state->comp_right);
#endif
/* Set up the output pointers */
out_U = planes[1]; /* U plane */
out_V = planes[2]; /* V plane */
/* Input starts at the first pixel of the compositing buffer */
in_U = state->comp_bufs[0]; /* U comp buffer */
in_V = state->comp_bufs[1]; /* V comp buffer */
in_A = state->comp_bufs[2]; /* A comp buffer */
/* Calculate how many pixels to blend based on the maximum X value that was
* drawn in the render_line function, divided by 2 (rounding up) to account
* for UV sub-sampling */
uv_end = (comp_last_x + 1) / 2;
left = state->comp_left / 2;
for (x = left; x < uv_end; x++) {
guint32 tmp;
/* Each entry in the compositing buffer is 4 summed pixels, so the
* inverse alpha is (4 * 0xff) - in_A[x] */
guint16 inv_A = (4 * 0xff) - in_A[x];
tmp = in_U[x] + inv_A * out_U[x];
out_U[x] = (guint8) (tmp / (4 * 0xff));
tmp = in_V[x] + inv_A * out_V[x];
out_V[x] = (guint8) (tmp / (4 * 0xff));
}
}