gstalpha.c 24.1 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26
/* GStreamer
 * Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
 *
 * 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 <gst/gst.h>
#include <gst/video/video.h>

#include <string.h>
27
#include <math.h>
28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44

#define GST_TYPE_ALPHA \
  (gst_alpha_get_type())
#define GST_ALPHA(obj) \
  (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_ALPHA,GstAlpha))
#define GST_ALPHA_CLASS(klass) \
  (G_TYPE_CHECK_CLASS_CAST((klass),GST_TYPE_ALPHA,GstAlphaClass))
#define GST_IS_ALPHA(obj) \
  (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_ALPHA))
#define GST_IS_ALPHA_CLASS(obj) \
  (G_TYPE_CHECK_CLASS_TYPE((klass),GST_TYPE_ALPHA))

typedef struct _GstAlpha GstAlpha;
typedef struct _GstAlphaClass GstAlphaClass;

typedef enum
{
45
  ALPHA_METHOD_SET,
46 47
  ALPHA_METHOD_GREEN,
  ALPHA_METHOD_BLUE,
48
  ALPHA_METHOD_CUSTOM,
49 50 51
}
GstAlphaMethod;

52
#define ROUND_UP_2(x) (((x) + 1) & ~1)
Wim Taymans's avatar
Wim Taymans committed
53 54
#define ROUND_UP_4(x) (((x) + 3) & ~3)
#define ROUND_UP_8(x) (((x) + 7) & ~7)
55 56 57 58 59 60 61 62 63 64 65 66

struct _GstAlpha
{
  GstElement element;

  /* pads */
  GstPad *sinkpad;
  GstPad *srcpad;

  /* caps */
  gint in_width, in_height;
  gint out_width, out_height;
67
  gboolean ayuv;
68 69 70

  gdouble alpha;

71 72 73
  guint target_r;
  guint target_g;
  guint target_b;
74 75

  GstAlphaMethod method;
76 77 78 79 80 81 82 83 84 85 86 87 88

  gfloat angle;
  gfloat noise_level;

  gfloat y;                     /* chroma color */
  gint8 cb, cr;
  gint8 kg;
  gfloat accept_angle_cos;
  gfloat accept_angle_sin;
  guint8 accept_angle_tg;
  guint8 accept_angle_ctg;
  guint8 one_over_kc;
  guint8 kfgy_scale;
89 90 91 92 93 94 95 96 97
};

struct _GstAlphaClass
{
  GstElementClass parent_class;
};

/* elementfactory information */
static GstElementDetails gst_alpha_details =
Wim Taymans's avatar
Wim Taymans committed
98
GST_ELEMENT_DETAILS ("Alpha filter",
99 100 101 102 103 104 105 106 107 108 109 110
    "Filter/Effect/Video",
    "Adds an alpha channel to video",
    "Wim Taymans <wim@fluendo.com>");


/* Alpha signals and args */
enum
{
  /* FILL ME */
  LAST_SIGNAL
};

111
#define DEFAULT_METHOD ALPHA_METHOD_SET
112 113 114 115 116 117 118
#define DEFAULT_ALPHA 1.0
#define DEFAULT_TARGET_R 0
#define DEFAULT_TARGET_G 255
#define DEFAULT_TARGET_B 0
#define DEFAULT_ANGLE 20.0
#define DEFAULT_NOISE_LEVEL 2.0

119 120 121 122 123
enum
{
  ARG_0,
  ARG_METHOD,
  ARG_ALPHA,
124 125 126 127 128
  ARG_TARGET_R,
  ARG_TARGET_G,
  ARG_TARGET_B,
  ARG_ANGLE,
  ARG_NOISE_LEVEL,
129 130 131 132 133 134 135 136 137 138 139
  /* FILL ME */
};

static GstStaticPadTemplate gst_alpha_src_template =
GST_STATIC_PAD_TEMPLATE ("src",
    GST_PAD_SRC,
    GST_PAD_ALWAYS,
    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV"))
    );

static GstStaticPadTemplate gst_alpha_sink_template =
140
    GST_STATIC_PAD_TEMPLATE ("sink",
141 142
    GST_PAD_SINK,
    GST_PAD_ALWAYS,
143 144 145
    GST_STATIC_CAPS (GST_VIDEO_CAPS_YUV ("AYUV")
        ";" GST_VIDEO_CAPS_YUV ("I420")
    )
146 147 148 149 150 151
    );


static void gst_alpha_base_init (gpointer g_class);
static void gst_alpha_class_init (GstAlphaClass * klass);
static void gst_alpha_init (GstAlpha * alpha);
152
static void gst_alpha_init_params (GstAlpha * alpha);
153 154 155 156 157 158

static void gst_alpha_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_alpha_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

159 160
static gboolean gst_alpha_sink_setcaps (GstPad * pad, GstCaps * caps);
static GstFlowReturn gst_alpha_chain (GstPad * pad, GstBuffer * buffer);
161

162 163
static GstStateChangeReturn gst_alpha_change_state (GstElement * element,
    GstStateChange transition);
164 165 166 167 168 169 170 171 172 173


static GstElementClass *parent_class = NULL;

#define GST_TYPE_ALPHA_METHOD (gst_alpha_method_get_type())
static GType
gst_alpha_method_get_type (void)
{
  static GType alpha_method_type = 0;
  static GEnumValue alpha_method[] = {
Thomas Vander Stichele's avatar
Thomas Vander Stichele committed
174 175 176 177
    {ALPHA_METHOD_SET, "Set/adjust alpha channel", "set"},
    {ALPHA_METHOD_GREEN, "Chroma Key green", "green"},
    {ALPHA_METHOD_BLUE, "Chroma Key blue", "blue"},
    {ALPHA_METHOD_CUSTOM, "Chroma Key on target_r/g/b", "custom"},
178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235
    {0, NULL, NULL},
  };

  if (!alpha_method_type) {
    alpha_method_type = g_enum_register_static ("GstAlphaMethod", alpha_method);
  }
  return alpha_method_type;
}

/* static guint gst_alpha_signals[LAST_SIGNAL] = { 0 }; */

GType
gst_alpha_get_type (void)
{
  static GType alpha_type = 0;

  if (!alpha_type) {
    static const GTypeInfo alpha_info = {
      sizeof (GstAlphaClass),
      gst_alpha_base_init,
      NULL,
      (GClassInitFunc) gst_alpha_class_init,
      NULL,
      NULL,
      sizeof (GstAlpha),
      0,
      (GInstanceInitFunc) gst_alpha_init,
    };

    alpha_type =
        g_type_register_static (GST_TYPE_ELEMENT, "GstAlpha", &alpha_info, 0);
  }
  return alpha_type;
}

static void
gst_alpha_base_init (gpointer g_class)
{
  GstElementClass *element_class = GST_ELEMENT_CLASS (g_class);

  gst_element_class_set_details (element_class, &gst_alpha_details);

  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_alpha_sink_template));
  gst_element_class_add_pad_template (element_class,
      gst_static_pad_template_get (&gst_alpha_src_template));
}
static void
gst_alpha_class_init (GstAlphaClass * klass)
{
  GObjectClass *gobject_class;
  GstElementClass *gstelement_class;

  gobject_class = (GObjectClass *) klass;
  gstelement_class = (GstElementClass *) klass;

  parent_class = g_type_class_ref (GST_TYPE_ELEMENT);

236 237 238
  gobject_class->set_property = gst_alpha_set_property;
  gobject_class->get_property = gst_alpha_get_property;

239 240 241 242 243 244 245
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_METHOD,
      g_param_spec_enum ("method", "Method",
          "How the alpha channels should be created", GST_TYPE_ALPHA_METHOD,
          DEFAULT_METHOD, (GParamFlags) G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ALPHA,
      g_param_spec_double ("alpha", "Alpha", "The value for the alpha channel",
          0.0, 1.0, DEFAULT_ALPHA, (GParamFlags) G_PARAM_READWRITE));
246 247 248 249 250 251 252 253 254 255 256 257 258 259 260
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET_R,
      g_param_spec_uint ("target_r", "Target Red", "The Red target", 0,
          255, DEFAULT_TARGET_R, (GParamFlags) G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET_G,
      g_param_spec_uint ("target_g", "Target Green", "The Green target", 0,
          255, DEFAULT_TARGET_G, (GParamFlags) G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_TARGET_B,
      g_param_spec_uint ("target_b", "Target Blue", "The Blue target",
          0, 255, DEFAULT_TARGET_B, (GParamFlags) G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_ANGLE,
      g_param_spec_float ("angle", "Angle", "Size of the colorcube to change",
          0.0, 90.0, DEFAULT_ANGLE, (GParamFlags) G_PARAM_READWRITE));
  g_object_class_install_property (G_OBJECT_CLASS (klass), ARG_NOISE_LEVEL,
      g_param_spec_float ("noise_level", "Noise Level", "Size of noise radius",
          0.0, 64.0, DEFAULT_NOISE_LEVEL, (GParamFlags) G_PARAM_READWRITE));
261 262 263 264 265 266 267 268 269

  gstelement_class->change_state = gst_alpha_change_state;
}

static void
gst_alpha_init (GstAlpha * alpha)
{
  /* create the sink and src pads */
  alpha->sinkpad =
270
      gst_pad_new_from_static_template (&gst_alpha_sink_template, "sink");
271 272
  gst_element_add_pad (GST_ELEMENT (alpha), alpha->sinkpad);
  gst_pad_set_chain_function (alpha->sinkpad, gst_alpha_chain);
273
  gst_pad_set_setcaps_function (alpha->sinkpad, gst_alpha_sink_setcaps);
274 275

  alpha->srcpad =
276
      gst_pad_new_from_static_template (&gst_alpha_src_template, "src");
277 278 279 280
  gst_element_add_pad (GST_ELEMENT (alpha), alpha->srcpad);

  alpha->alpha = DEFAULT_ALPHA;
  alpha->method = DEFAULT_METHOD;
281 282 283 284 285
  alpha->target_r = DEFAULT_TARGET_R;
  alpha->target_g = DEFAULT_TARGET_G;
  alpha->target_b = DEFAULT_TARGET_B;
  alpha->angle = DEFAULT_ANGLE;
  alpha->noise_level = DEFAULT_NOISE_LEVEL;
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301
}

/* do we need this function? */
static void
gst_alpha_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstAlpha *alpha;

  g_return_if_fail (GST_IS_ALPHA (object));

  alpha = GST_ALPHA (object);

  switch (prop_id) {
    case ARG_METHOD:
      alpha->method = g_value_get_enum (value);
302 303 304 305 306 307 308 309 310 311 312 313 314 315 316
      switch (alpha->method) {
        case ALPHA_METHOD_GREEN:
          alpha->target_r = 0;
          alpha->target_g = 255;
          alpha->target_b = 0;
          break;
        case ALPHA_METHOD_BLUE:
          alpha->target_r = 0;
          alpha->target_g = 0;
          alpha->target_b = 255;
          break;
        default:
          break;
      }
      gst_alpha_init_params (alpha);
317 318 319 320
      break;
    case ARG_ALPHA:
      alpha->alpha = g_value_get_double (value);
      break;
321 322 323 324 325 326 327 328 329 330 331
    case ARG_TARGET_R:
      alpha->target_r = g_value_get_uint (value);
      gst_alpha_init_params (alpha);
      break;
    case ARG_TARGET_G:
      alpha->target_g = g_value_get_uint (value);
      gst_alpha_init_params (alpha);
      break;
    case ARG_TARGET_B:
      alpha->target_b = g_value_get_uint (value);
      gst_alpha_init_params (alpha);
332
      break;
333 334 335 336 337 338 339
    case ARG_ANGLE:
      alpha->angle = g_value_get_float (value);
      gst_alpha_init_params (alpha);
      break;
    case ARG_NOISE_LEVEL:
      alpha->noise_level = g_value_get_float (value);
      gst_alpha_init_params (alpha);
340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}
static void
gst_alpha_get_property (GObject * object, guint prop_id, GValue * value,
    GParamSpec * pspec)
{
  GstAlpha *alpha;

  g_return_if_fail (GST_IS_ALPHA (object));

  alpha = GST_ALPHA (object);

  switch (prop_id) {
    case ARG_METHOD:
      g_value_set_enum (value, alpha->method);
      break;
    case ARG_ALPHA:
      g_value_set_double (value, alpha->alpha);
      break;
363 364 365 366 367 368 369 370
    case ARG_TARGET_R:
      g_value_set_uint (value, alpha->target_r);
      break;
    case ARG_TARGET_G:
      g_value_set_uint (value, alpha->target_g);
      break;
    case ARG_TARGET_B:
      g_value_set_uint (value, alpha->target_b);
371
      break;
372 373 374 375 376
    case ARG_ANGLE:
      g_value_set_float (value, alpha->angle);
      break;
    case ARG_NOISE_LEVEL:
      g_value_set_float (value, alpha->noise_level);
377 378 379 380 381 382 383
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

384 385
static gboolean
gst_alpha_sink_setcaps (GstPad * pad, GstCaps * caps)
386 387 388 389
{
  GstAlpha *alpha;
  GstStructure *structure;
  gboolean ret;
390
  guint32 fourcc;
391

392
  alpha = GST_ALPHA (GST_PAD_PARENT (pad));
393 394
  structure = gst_caps_get_structure (caps, 0);

395 396 397 398 399 400 401 402 403
  if (gst_structure_get_fourcc (structure, "format", &fourcc)) {
    switch (fourcc) {
      case GST_MAKE_FOURCC ('I', '4', '2', '0'):
        alpha->ayuv = FALSE;
        break;
      case GST_MAKE_FOURCC ('A', 'Y', 'U', 'V'):
        alpha->ayuv = TRUE;
        break;
      default:
404
        return FALSE;
405 406
    }
  } else {
407
    return FALSE;
408 409
  }

410 411 412
  ret = gst_structure_get_int (structure, "width", &alpha->in_width);
  ret &= gst_structure_get_int (structure, "height", &alpha->in_height);

413
  return TRUE;
414 415 416
}

static void
417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447
gst_alpha_set_ayuv (guint8 * src, guint8 * dest, gint width, gint height,
    gdouble alpha)
{
  gint b_alpha = (gint) (alpha * 255);
  gint i, j;
  gint size;
  gint stride;
  gint wrap;

  width = ROUND_UP_2 (width);
  height = ROUND_UP_2 (height);

  stride = ROUND_UP_4 (width);
  size = stride * height;

  wrap = stride - width;

  for (i = 0; i < height; i++) {
    for (j = 0; j < width; j++) {
      *dest++ = (*src++ * b_alpha) >> 8;
      *dest++ = *src++;
      *dest++ = *src++;
      *dest++ = *src++;
    }
    src += wrap;
    dest += wrap;
  }
}

static void
gst_alpha_set_i420 (guint8 * src, guint8 * dest, gint width, gint height,
448 449 450 451 452 453 454
    gdouble alpha)
{
  gint b_alpha = (gint) (alpha * 255);
  guint8 *srcY;
  guint8 *srcU;
  guint8 *srcV;
  gint i, j;
455 456 457 458
  gint size, size2;
  gint stride, stride2;
  gint wrap, wrap2;

Wim Taymans's avatar
Wim Taymans committed
459 460 461
  width = ROUND_UP_2 (width);
  height = ROUND_UP_2 (height);

462 463
  stride = ROUND_UP_4 (width);
  size = stride * height;
Wim Taymans's avatar
Wim Taymans committed
464 465
  stride2 = ROUND_UP_8 (width) / 2;
  size2 = stride2 * height / 2;
466

467 468
  wrap = stride - 2 * (width / 2);
  wrap2 = stride2 - width / 2;
469 470 471

  srcY = src;
  srcU = srcY + size;
472
  srcV = srcU + size2;
473 474 475 476 477 478 479 480 481 482 483 484 485

  for (i = 0; i < height; i++) {
    for (j = 0; j < width / 2; j++) {
      *dest++ = b_alpha;
      *dest++ = *srcY++;
      *dest++ = *srcU;
      *dest++ = *srcV;
      *dest++ = b_alpha;
      *dest++ = *srcY++;
      *dest++ = *srcU++;
      *dest++ = *srcV++;
    }
    if (i % 2 == 0) {
486 487 488 489 490
      srcU -= width / 2;
      srcV -= width / 2;
    } else {
      srcU += wrap2;
      srcV += wrap2;
491
    }
492
    srcY += wrap;
493 494 495
  }
}

496
static void
497
gst_alpha_chroma_key_ayuv (guint8 * src, guint8 * dest, gint width, gint height,
498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603
    GstAlpha * alpha)
{
  gint b_alpha;
  guint8 *src1;
  guint8 *dest1;
  gint i, j;
  gint x, z, u, v, y, a;
  gint size;
  gint stride;
  gint wrap;
  gint tmp, tmp1;
  gint x1, y1;

  width = ROUND_UP_2 (width);
  height = ROUND_UP_2 (height);

  stride = ROUND_UP_4 (width);
  size = stride * height;

  src1 = src;
  dest1 = dest;

  wrap = stride - width;

  for (i = 0; i < height; i++) {
    for (j = 0; j < width; j++) {
      a = *src1++ * (alpha->alpha);
      y = *src1++;
      u = *src1++ - 128;
      v = *src1++ - 128;

      /* Convert foreground to XZ coords where X direction is defined by
         the key color */
      tmp = ((short) u * alpha->cb + (short) v * alpha->cr) >> 7;
      x = CLAMP (tmp, -128, 127);
      tmp = ((short) v * alpha->cb - (short) u * alpha->cr) >> 7;
      z = CLAMP (tmp, -128, 127);

      /* WARNING: accept angle should never be set greater than "somewhat less
         than 90 degrees" to avoid dealing with negative/infinite tg. In reality,
         80 degrees should be enough if foreground is reasonable. If this seems
         to be a problem, go to alternative ways of checking point position
         (scalar product or line equations). This angle should not be too small
         either to avoid infinite ctg (used to suppress foreground without use of
         division) */

      tmp = ((short) (x) * alpha->accept_angle_tg) >> 4;
      tmp = MIN (tmp, 127);

      if (abs (z) > tmp) {
        /* keep foreground Kfg = 0 */
        b_alpha = a;
      } else {
        /* Compute Kfg (implicitly) and Kbg, suppress foreground in XZ coord
           according to Kfg */
        tmp = ((short) (z) * alpha->accept_angle_ctg) >> 4;
        tmp = CLAMP (tmp, -128, 127);
        x1 = abs (tmp);
        y1 = z;

        tmp1 = x - x1;
        tmp1 = MAX (tmp1, 0);
        b_alpha = (((unsigned char) (tmp1) *
                (unsigned short) (alpha->one_over_kc)) / 2);
        b_alpha = 255 - CLAMP (b_alpha, 0, 255);
        b_alpha = (a * b_alpha) >> 8;

        tmp = ((unsigned short) (tmp1) * alpha->kfgy_scale) >> 4;
        tmp1 = MIN (tmp, 255);

        tmp = y - tmp1;
        y = MAX (tmp, 0);

        /* Convert suppressed foreground back to CbCr */
        tmp = ((char) (x1) * (short) (alpha->cb) -
            (char) (y1) * (short) (alpha->cr)) >> 7;
        u = CLAMP (tmp, -128, 127);

        tmp = ((char) (x1) * (short) (alpha->cr) +
            (char) (y1) * (short) (alpha->cb)) >> 7;
        v = CLAMP (tmp, -128, 127);

        /* Deal with noise. For now, a circle around the key color with
           radius of noise_level treated as exact key color. Introduces
           sharp transitions.
         */
        tmp = z * (short) (z) + (x - alpha->kg) * (short) (x - alpha->kg);
        tmp = MIN (tmp, 0xffff);

        if (tmp < alpha->noise_level * alpha->noise_level) {
          b_alpha = 0;
        }
      }

      u += 128;
      v += 128;

      *dest1++ = b_alpha;
      *dest1++ = y;
      *dest1++ = u;
      *dest1++ = v;
    }
    dest1 += wrap;
    src1 += wrap;
  }
}
604

605 606
/* based on http://www.cs.utah.edu/~michael/chroma/
 */
607
static void
608
gst_alpha_chroma_key_i420 (guint8 * src, guint8 * dest, gint width, gint height,
609
    GstAlpha * alpha)
610 611 612 613 614
{
  gint b_alpha;
  guint8 *srcY1, *srcY2, *srcU, *srcV;
  guint8 *dest1, *dest2;
  gint i, j;
615
  gint x, z, u, v, y11, y12, y21, y22, a;
616 617 618
  gint size, size2;
  gint stride, stride2;
  gint wrap, wrap2, wrap3;
619 620
  gint tmp, tmp1;
  gint x1, y1;
621

Wim Taymans's avatar
Wim Taymans committed
622 623 624
  width = ROUND_UP_2 (width);
  height = ROUND_UP_2 (height);

625 626
  stride = ROUND_UP_4 (width);
  size = stride * height;
Wim Taymans's avatar
Wim Taymans committed
627 628
  stride2 = ROUND_UP_8 (width) / 2;
  size2 = stride2 * height / 2;
629 630

  srcY1 = src;
631
  srcY2 = src + stride;
632
  srcU = srcY1 + size;
633
  srcV = srcU + size2;
634 635 636 637

  dest1 = dest;
  dest2 = dest + width * 4;

638 639
  wrap = 2 * stride - 2 * (width / 2);
  wrap2 = stride2 - width / 2;
Wim Taymans's avatar
Wim Taymans committed
640
  wrap3 = 8 * width - 8 * (width / 2);
641

642 643
  a = 255 * alpha->alpha;

644 645
  for (i = 0; i < height / 2; i++) {
    for (j = 0; j < width / 2; j++) {
646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686
      y11 = *srcY1++;
      y12 = *srcY1++;
      y21 = *srcY2++;
      y22 = *srcY2++;
      u = *srcU++ - 128;
      v = *srcV++ - 128;

      /* Convert foreground to XZ coords where X direction is defined by
         the key color */
      tmp = ((short) u * alpha->cb + (short) v * alpha->cr) >> 7;
      x = CLAMP (tmp, -128, 127);
      tmp = ((short) v * alpha->cb - (short) u * alpha->cr) >> 7;
      z = CLAMP (tmp, -128, 127);

      /* WARNING: accept angle should never be set greater than "somewhat less
         than 90 degrees" to avoid dealing with negative/infinite tg. In reality,
         80 degrees should be enough if foreground is reasonable. If this seems
         to be a problem, go to alternative ways of checking point position
         (scalar product or line equations). This angle should not be too small
         either to avoid infinite ctg (used to suppress foreground without use of
         division) */

      tmp = ((short) (x) * alpha->accept_angle_tg) >> 4;
      tmp = MIN (tmp, 127);

      if (abs (z) > tmp) {
        /* keep foreground Kfg = 0 */
        b_alpha = 255;
      } else {
        /* Compute Kfg (implicitly) and Kbg, suppress foreground in XZ coord
           according to Kfg */
        tmp = ((short) (z) * alpha->accept_angle_ctg) >> 4;
        tmp = CLAMP (tmp, -128, 127);
        x1 = abs (tmp);
        y1 = z;

        tmp1 = x - x1;
        tmp1 = MAX (tmp1, 0);
        b_alpha = (((unsigned char) (tmp1) *
                (unsigned short) (alpha->one_over_kc)) / 2);
        b_alpha = 255 - CLAMP (b_alpha, 0, 255);
687
        b_alpha = (a * b_alpha) >> 8;
688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718

        tmp = ((unsigned short) (tmp1) * alpha->kfgy_scale) >> 4;
        tmp1 = MIN (tmp, 255);

        tmp = y11 - tmp1;
        y11 = MAX (tmp, 0);
        tmp = y12 - tmp1;
        y12 = MAX (tmp, 0);
        tmp = y21 - tmp1;
        y21 = MAX (tmp, 0);
        tmp = y22 - tmp1;
        y22 = MAX (tmp, 0);

        /* Convert suppressed foreground back to CbCr */
        tmp = ((char) (x1) * (short) (alpha->cb) -
            (char) (y1) * (short) (alpha->cr)) >> 7;
        u = CLAMP (tmp, -128, 127);

        tmp = ((char) (x1) * (short) (alpha->cr) +
            (char) (y1) * (short) (alpha->cb)) >> 7;
        v = CLAMP (tmp, -128, 127);

        /* Deal with noise. For now, a circle around the key color with
           radius of noise_level treated as exact key color. Introduces
           sharp transitions.
         */
        tmp = z * (short) (z) + (x - alpha->kg) * (short) (x - alpha->kg);
        tmp = MIN (tmp, 0xffff);

        if (tmp < alpha->noise_level * alpha->noise_level) {
          /* Uncomment this if you want total suppression within the noise circle */
719 720 721 722
          b_alpha = 0;
        }
      }

723 724 725
      u += 128;
      v += 128;

726
      *dest1++ = b_alpha;
727
      *dest1++ = y11;
728 729 730
      *dest1++ = u;
      *dest1++ = v;
      *dest1++ = b_alpha;
731
      *dest1++ = y12;
732 733 734
      *dest1++ = u;
      *dest1++ = v;
      *dest2++ = b_alpha;
735
      *dest2++ = y21;
736 737 738
      *dest2++ = u;
      *dest2++ = v;
      *dest2++ = b_alpha;
739
      *dest2++ = y22;
740 741 742
      *dest2++ = u;
      *dest2++ = v;
    }
743 744 745 746 747 748
    dest1 += wrap3;
    dest2 += wrap3;
    srcY1 += wrap;
    srcY2 += wrap;
    srcU += wrap2;
    srcV += wrap2;
749 750 751
  }
}

752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787
static void
gst_alpha_init_params (GstAlpha * alpha)
{
  float kgl;
  float tmp;
  float tmp1, tmp2;

  alpha->y =
      0.257 * alpha->target_r + 0.504 * alpha->target_g +
      0.098 * alpha->target_b;
  tmp1 =
      -0.148 * alpha->target_r - 0.291 * alpha->target_g +
      0.439 * alpha->target_b;
  tmp2 =
      0.439 * alpha->target_r - 0.368 * alpha->target_g -
      0.071 * alpha->target_b;
  kgl = sqrt (tmp1 * tmp1 + tmp2 * tmp2);
  alpha->cb = 127 * (tmp1 / kgl);
  alpha->cr = 127 * (tmp2 / kgl);

  alpha->accept_angle_cos = cos (M_PI * alpha->angle / 180);
  alpha->accept_angle_sin = sin (M_PI * alpha->angle / 180);
  tmp = 15 * tan (M_PI * alpha->angle / 180);
  tmp = MIN (tmp, 255);
  alpha->accept_angle_tg = tmp;
  tmp = 15 / tan (M_PI * alpha->angle / 180);
  tmp = MIN (tmp, 255);
  alpha->accept_angle_ctg = tmp;
  tmp = 1 / (kgl);
  alpha->one_over_kc = 255 * 2 * tmp - 255;
  tmp = 15 * (float) (alpha->y) / kgl;
  tmp = MIN (tmp, 255);
  alpha->kfgy_scale = tmp;
  alpha->kg = MIN (kgl, 127);
}

788 789
static GstFlowReturn
gst_alpha_chain (GstPad * pad, GstBuffer * buffer)
790 791 792 793
{
  GstAlpha *alpha;
  GstBuffer *outbuf;
  gint new_width, new_height;
794
  GstFlowReturn ret;
795

796
  alpha = GST_ALPHA (GST_PAD_PARENT (pad));
797 798 799 800 801

  new_width = alpha->in_width;
  new_height = alpha->in_height;

  if (new_width != alpha->out_width ||
802
      new_height != alpha->out_height || !GST_PAD_CAPS (alpha->srcpad)) {
803 804 805 806 807 808 809
    GstCaps *newcaps;

    newcaps = gst_caps_copy (gst_pad_get_negotiated_caps (alpha->sinkpad));
    gst_caps_set_simple (newcaps,
        "format", GST_TYPE_FOURCC, GST_STR_FOURCC ("AYUV"),
        "width", G_TYPE_INT, new_width, "height", G_TYPE_INT, new_height, NULL);

810
    gst_pad_set_caps (alpha->srcpad, newcaps);
811 812 813 814 815

    alpha->out_width = new_width;
    alpha->out_height = new_height;
  }

Wim Taymans's avatar
Wim Taymans committed
816 817 818
  outbuf =
      gst_buffer_new_and_alloc (ROUND_UP_2 (new_width) *
      ROUND_UP_2 (new_height) * 4);
819
  gst_buffer_set_caps (outbuf, GST_PAD_CAPS (alpha->srcpad));
820 821 822 823
  GST_BUFFER_TIMESTAMP (outbuf) = GST_BUFFER_TIMESTAMP (buffer);
  GST_BUFFER_DURATION (outbuf) = GST_BUFFER_DURATION (buffer);

  switch (alpha->method) {
824 825 826 827 828 829 830 831
    case ALPHA_METHOD_SET:
      if (alpha->ayuv) {
        gst_alpha_set_ayuv (GST_BUFFER_DATA (buffer),
            GST_BUFFER_DATA (outbuf), new_width, new_height, alpha->alpha);
      } else {
        gst_alpha_set_i420 (GST_BUFFER_DATA (buffer),
            GST_BUFFER_DATA (outbuf), new_width, new_height, alpha->alpha);
      }
832 833 834
      break;
    case ALPHA_METHOD_GREEN:
    case ALPHA_METHOD_BLUE:
835
    case ALPHA_METHOD_CUSTOM:
836 837 838 839 840 841 842
      if (alpha->ayuv) {
        gst_alpha_chroma_key_ayuv (GST_BUFFER_DATA (buffer),
            GST_BUFFER_DATA (outbuf), new_width, new_height, alpha);
      } else {
        gst_alpha_chroma_key_i420 (GST_BUFFER_DATA (buffer),
            GST_BUFFER_DATA (outbuf), new_width, new_height, alpha);
      }
843 844 845
      break;
    default:
      break;
846 847 848 849
  }

  gst_buffer_unref (buffer);

850 851 852
  ret = gst_pad_push (alpha->srcpad, outbuf);

  return ret;
853 854
}

855 856
static GstStateChangeReturn
gst_alpha_change_state (GstElement * element, GstStateChange transition)
857
{
858
  GstStateChangeReturn res;
859 860 861 862
  GstAlpha *alpha;

  alpha = GST_ALPHA (element);

863 864
  switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
865
      break;
866
    case GST_STATE_CHANGE_READY_TO_PAUSED:
867
      gst_alpha_init_params (alpha);
868
      break;
869
    case GST_STATE_CHANGE_PAUSED_TO_PLAYING:
870
    default:
871
      break;
872 873 874 875 876
  }

  res = parent_class->change_state (element, transition);

  switch (transition) {
877 878 879
    case GST_STATE_CHANGE_PLAYING_TO_PAUSED:
    case GST_STATE_CHANGE_PAUSED_TO_READY:
    case GST_STATE_CHANGE_READY_TO_NULL:
880
    default:
881 882 883
      break;
  }

884
  return res;
885 886 887 888 889 890 891 892 893 894 895
}

static gboolean
plugin_init (GstPlugin * plugin)
{
  return gst_element_register (plugin, "alpha", GST_RANK_NONE, GST_TYPE_ALPHA);
}

GST_PLUGIN_DEFINE (GST_VERSION_MAJOR,
    GST_VERSION_MINOR,
    "alpha",
896
    "adds an alpha channel to video",
897
    plugin_init, VERSION, GST_LICENSE, GST_PACKAGE_NAME, GST_PACKAGE_ORIGIN)