3 * Copyright (C) 2007 David Schleef <ds@schleef.org>
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Library General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Library General Public License for more details.
15 * You should have received a copy of the GNU Library General Public
16 * License along with this library; if not, write to the
17 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
18 * Boston, MA 02111-1307, USA.
21 * Logic enhanced by William Brack <wbrack@mmm.com.hk>
25 * SECTION:element-bayer2rgb
27 * Decodes raw camera bayer (fourcc BA81) to RGB.
31 * In order to guard against my advancing maturity, some extra detailed
32 * information about the logic of the decode is included here. Much of
33 * this was inspired by a technical paper from siliconimaging.com, which
34 * in turn was based upon an article from IEEE,
35 * T. Sakamoto, C. Nakanishi and T. Hase,
36 * “Software pixel interpolation for digital still cameras suitable for
38 * IEEE Trans. Consumer Electronics, vol. 44, no. 4, November 1998.
40 * The code assumes a Bayer matrix of the type produced by the fourcc
41 * BA81 (v4l2 format SBGGR8) of width w and height h which looks like:
51 * We expand this matrix, producing a separate {r, g, b} triple for each
52 * of the individual elements. The algorithm for doing this expansion is
55 * We are designing for speed of transformation, at a slight expense of code.
56 * First, we calculate the appropriate triples for the four corners, the
57 * remainder of the top and bottom rows, and the left and right columns.
58 * The reason for this is that those elements are transformed slightly
59 * differently than all of the remainder of the matrix. Finally, we transform
60 * all of the remainder.
62 * The transformation into the "appropriate triples" is based upon the
63 * "nearest neighbor" principal, with some additional complexity for the
64 * calculation of the "green" element, where an "adaptive" pairing is used.
66 * For purposes of documentation and indentification, each element of the
67 * original array can be put into one of four classes:
70 * GR A green element which is followed by a red one
71 * GB A green element which is followed by a blue one
79 #include <gst/base/gstbasetransform.h>
80 #include <gst/video/video.h>
85 #define GST_CAT_DEFAULT gst_bayer2rgb_debug
86 GST_DEBUG_CATEGORY_STATIC (GST_CAT_DEFAULT);
88 #define GST_TYPE_BAYER2RGB (gst_bayer2rgb_get_type())
89 #define GST_BAYER2RGB(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BAYER2RGB,GstBayer2RGB))
90 #define GST_IS_BAYER2RGB(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BAYER2RGB))
91 #define GST_BAYER2RGB_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass) ,GST_TYPE_BAYER2RGB,GstBayer2RGBClass))
92 #define GST_IS_BAYER2RGB_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass) ,GST_TYPE_BAYER2RGB))
93 #define GST_BAYER2RGB_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS((obj) ,GST_TYPE_BAYER2RGB,GstBayer2RGBClass))
94 typedef struct _GstBayer2RGB GstBayer2RGB;
95 typedef struct _GstBayer2RGBClass GstBayer2RGBClass;
97 typedef void (*GstBayer2RGBProcessFunc) (GstBayer2RGB *, guint8 *, guint);
101 GstBaseTransform basetransform;
107 int pixsize; /* bytes per pixel */
108 int r_off; /* offset for red */
109 int g_off; /* offset for green */
110 int b_off; /* offset for blue */
113 struct _GstBayer2RGBClass
115 GstBaseTransformClass parent;
118 //#define SRC_CAPS GST_VIDEO_CAPS_RGBx
120 GST_VIDEO_CAPS_RGBx ";" \
121 GST_VIDEO_CAPS_xRGB ";" \
122 GST_VIDEO_CAPS_BGRx ";" \
123 GST_VIDEO_CAPS_xBGR ";" \
124 GST_VIDEO_CAPS_RGBA ";" \
125 GST_VIDEO_CAPS_ARGB ";" \
126 GST_VIDEO_CAPS_BGRA ";" \
127 GST_VIDEO_CAPS_ABGR ";" \
128 GST_VIDEO_CAPS_RGB ";" \
131 #define SINK_CAPS "video/x-raw-bayer,width=(int)[1,MAX],height=(int)[1,MAX]"
138 #define DEBUG_INIT(bla) \
139 GST_DEBUG_CATEGORY_INIT (gst_bayer2rgb_debug, "bayer2rgb", 0, "bayer2rgb element");
141 GType gst_bayer2rgb_get_type (void);
142 GST_BOILERPLATE_FULL (GstBayer2RGB, gst_bayer2rgb, GstBaseTransform,
143 GST_TYPE_BASE_TRANSFORM, DEBUG_INIT);
145 static void gst_bayer2rgb_set_property (GObject * object, guint prop_id,
146 const GValue * value, GParamSpec * pspec);
147 static void gst_bayer2rgb_get_property (GObject * object, guint prop_id,
148 GValue * value, GParamSpec * pspec);
150 static gboolean gst_bayer2rgb_set_caps (GstBaseTransform * filter,
151 GstCaps * incaps, GstCaps * outcaps);
152 static GstFlowReturn gst_bayer2rgb_transform (GstBaseTransform * base,
153 GstBuffer * inbuf, GstBuffer * outbuf);
154 static void gst_bayer2rgb_reset (GstBayer2RGB * filter);
155 static GstCaps *gst_bayer2rgb_transform_caps (GstBaseTransform * base,
156 GstPadDirection direction, GstCaps * caps);
157 static gboolean gst_bayer2rgb_get_unit_size (GstBaseTransform * base,
158 GstCaps * caps, guint * size);
162 gst_bayer2rgb_base_init (gpointer klass)
164 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
166 gst_element_class_set_details_simple (element_class,
167 "Bayer to RGB decoder for cameras", "Filter/Converter/Video",
168 "Converts video/x-raw-bayer to video/x-raw-rgb",
169 "William Brack <wbrack@mmm.com.hk>");
171 gst_element_class_add_pad_template (element_class,
172 gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
173 gst_caps_from_string (SRC_CAPS)));
174 gst_element_class_add_pad_template (element_class,
175 gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
176 gst_caps_from_string (SINK_CAPS)));
180 gst_bayer2rgb_class_init (GstBayer2RGBClass * klass)
182 GObjectClass *gobject_class;
184 gobject_class = (GObjectClass *) klass;
185 gobject_class->set_property = gst_bayer2rgb_set_property;
186 gobject_class->get_property = gst_bayer2rgb_get_property;
188 GST_BASE_TRANSFORM_CLASS (klass)->transform_caps =
189 GST_DEBUG_FUNCPTR (gst_bayer2rgb_transform_caps);
190 GST_BASE_TRANSFORM_CLASS (klass)->get_unit_size =
191 GST_DEBUG_FUNCPTR (gst_bayer2rgb_get_unit_size);
192 GST_BASE_TRANSFORM_CLASS (klass)->set_caps =
193 GST_DEBUG_FUNCPTR (gst_bayer2rgb_set_caps);
194 GST_BASE_TRANSFORM_CLASS (klass)->transform =
195 GST_DEBUG_FUNCPTR (gst_bayer2rgb_transform);
199 gst_bayer2rgb_init (GstBayer2RGB * filter, GstBayer2RGBClass * klass)
201 gst_bayer2rgb_reset (filter);
202 gst_base_transform_set_in_place (GST_BASE_TRANSFORM (filter), TRUE);
205 /* No properties are implemented, so only a warning is produced */
207 gst_bayer2rgb_set_property (GObject * object, guint prop_id,
208 const GValue * value, GParamSpec * pspec)
213 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
219 gst_bayer2rgb_get_property (GObject * object, guint prop_id,
220 GValue * value, GParamSpec * pspec)
225 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
230 /* Routine to convert colormask value into relative byte offset */
232 get_pix_offset (int mask, int bpp)
234 int bpp32 = (bpp / 8) - 3;
246 GST_ERROR ("Invalid color mask 0x%08x", mask);
252 gst_bayer2rgb_set_caps (GstBaseTransform * base, GstCaps * incaps,
255 GstBayer2RGB *filter = GST_BAYER2RGB (base);
256 GstStructure *structure;
259 GST_DEBUG ("in caps %" GST_PTR_FORMAT " out caps %" GST_PTR_FORMAT, incaps,
262 structure = gst_caps_get_structure (incaps, 0);
264 gst_structure_get_int (structure, "width", &filter->width);
265 gst_structure_get_int (structure, "height", &filter->height);
266 filter->stride = GST_ROUND_UP_4 (filter->width);
268 /* To cater for different RGB formats, we need to set params for later */
269 structure = gst_caps_get_structure (outcaps, 0);
270 gst_structure_get_int (structure, "bpp", &bpp);
271 filter->pixsize = bpp / 8;
272 gst_structure_get_int (structure, "red_mask", &val);
273 filter->r_off = get_pix_offset (val, bpp);
274 gst_structure_get_int (structure, "green_mask", &val);
275 filter->g_off = get_pix_offset (val, bpp);
276 gst_structure_get_int (structure, "blue_mask", &val);
277 filter->b_off = get_pix_offset (val, bpp);
283 gst_bayer2rgb_reset (GstBayer2RGB * filter)
295 gst_bayer2rgb_transform_caps (GstBaseTransform * base,
296 GstPadDirection direction, GstCaps * caps)
298 GstStructure *structure;
300 GstStructure *newstruct;
302 GST_DEBUG_OBJECT (caps, "transforming caps (from)");
304 structure = gst_caps_get_structure (caps, 0);
306 if (direction == GST_PAD_SRC) {
307 newcaps = gst_caps_new_simple ("video/x-raw-bayer", NULL);
309 newcaps = gst_caps_new_simple ("video/x-raw-rgb", NULL);
311 newstruct = gst_caps_get_structure (newcaps, 0);
313 gst_structure_set_value (newstruct, "width",
314 gst_structure_get_value (structure, "width"));
315 gst_structure_set_value (newstruct, "height",
316 gst_structure_get_value (structure, "height"));
317 gst_structure_set_value (newstruct, "framerate",
318 gst_structure_get_value (structure, "framerate"));
320 GST_DEBUG_OBJECT (newcaps, "transforming caps (into)");
326 gst_bayer2rgb_get_unit_size (GstBaseTransform * base, GstCaps * caps,
329 GstStructure *structure;
335 structure = gst_caps_get_structure (caps, 0);
337 if (gst_structure_get_int (structure, "width", &width) &&
338 gst_structure_get_int (structure, "height", &height)) {
339 name = gst_structure_get_name (structure);
340 /* Our name must be either video/x-raw-bayer video/x-raw-rgb */
341 if (strcmp (name, "video/x-raw-rgb")) {
342 /* For bayer, we handle only BA81 (BGGR), which is BPP=24 */
343 *size = GST_ROUND_UP_4 (width) * height;
346 /* For output, calculate according to format */
347 if (gst_structure_get_int (structure, "bpp", &pixsize)) {
348 *size = width * height * (pixsize / 8);
354 GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
355 ("Incomplete caps, some required field missing"));
360 * We define values for the colors, just to make the code more readable.
362 #define RED 0 /* Pure red element */
363 #define GREENB 1 /* Green element which is on a blue line */
364 #define BLUE 2 /* Pure blue element */
365 #define GREENR 3 /* Green element which is on a red line */
367 /* Routine to generate the top and bottom edges (not including corners) */
369 hborder (uint8_t * input, uint8_t * output, int bot_top,
370 int typ, GstBayer2RGB * filter)
372 uint8_t *op; /* output pointer */
373 uint8_t *ip; /* input pointer */
374 uint8_t *nx; /* next line pointer */
375 int ix; /* loop index */
377 op = output + (bot_top * filter->width * (filter->height - 1) + 1) *
379 ip = input + bot_top * filter->stride * (filter->height - 1);
380 /* calculate minus or plus one line, depending upon bot_top flag */
381 nx = ip + (1 - 2 * bot_top) * filter->stride;
382 /* Stepping horizontally */
383 for (ix = 1; ix < filter->width - 1; ix++, op += filter->pixsize) {
386 op[filter->r_off] = ip[ix];
387 op[filter->g_off] = (ip[ix + 1] + ip[ix - 1] + nx[ix] + 1) / 3;
388 op[filter->b_off] = (nx[ix + 1] + nx[ix - 1] + 1) / 2;
392 op[filter->r_off] = (ip[ix + 1] + ip[ix - 1] + 1) / 2;
393 op[filter->g_off] = ip[ix];
394 op[filter->b_off] = nx[ix];
398 op[filter->r_off] = nx[ix];
399 op[filter->g_off] = ip[ix];
400 op[filter->b_off] = (ip[ix + 1] + ip[ix - 1] + 1) / 2;
404 op[filter->r_off] = (nx[ix + 1] + nx[ix - 1] + 1) / 2;
405 op[filter->g_off] = (ip[ix + 1] + ip[ix - 1] + nx[ix] + 1) / 3;
406 op[filter->b_off] = ip[ix];
413 /* Routine to generate the left and right edges, not including corners */
415 vborder (uint8_t * input, uint8_t * output, int right_left,
416 int typ, GstBayer2RGB * filter)
418 uint8_t *op; /* output pointer */
419 uint8_t *ip; /* input pointer */
420 uint8_t *la; /* line above pointer */
421 uint8_t *lb; /* line below pointer */
422 int ix; /* loop index */
423 int lr; /* 'left-right' flag - +1 is right, -1 is left */
425 lr = (1 - 2 * right_left);
426 /* stepping vertically */
427 for (ix = 1; ix < filter->height - 1; ix++) {
428 ip = input + right_left * (filter->width - 1) + ix * filter->stride;
429 op = output + (right_left * (filter->width - 1) + ix * filter->width) *
431 la = ip + filter->stride;
432 lb = ip - filter->stride;
435 op[filter->r_off] = ip[0];
436 op[filter->g_off] = (la[0] + ip[lr] + lb[0] + 1) / 3;
437 op[filter->b_off] = (la[lr] + lb[lr] + 1) / 2;
441 op[filter->r_off] = ip[lr];
442 op[filter->g_off] = ip[0];
443 op[filter->b_off] = (la[lr] + lb[lr] + 1) / 2;
447 op[filter->r_off] = (la[lr] + lb[lr] + 1) / 2;
448 op[filter->g_off] = ip[0];
449 op[filter->b_off] = ip[lr];
453 op[filter->r_off] = (la[lr] + lb[lr] + 1) / 2;
454 op[filter->g_off] = (la[0] + ip[lr] + lb[0] + 1) / 3;
455 op[filter->b_off] = ip[0];
462 /* Produce the four (top, bottom, left, right) edges */
464 do_row0_col0 (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
468 /* Horizontal edges */
469 hborder (input, output, 0, GREENB, filter);
470 if (filter->height & 1)
471 type = GREENB; /* odd # rows, "bottom" edge same as top */
473 type = RED; /* even #, bottom side different */
474 hborder (input, output, 1, type, filter);
477 vborder (input, output, 0, GREENR, filter);
478 if (filter->width & 1)
479 type = GREENR; /* odd # cols, "right" edge same as left */
481 type = RED; /* even #, right side different */
482 vborder (input, output, 1, type, filter);
486 corner (uint8_t * input, uint8_t * output, int x, int y,
487 int xd, int yd, int typ, GstBayer2RGB * filter)
489 uint8_t *ip; /* input pointer */
490 uint8_t *op; /* output pointer */
491 uint8_t *nx; /* adjacent line */
493 op = output + y * filter->width * filter->pixsize + x * filter->pixsize;
494 ip = input + y * filter->stride + x;
495 nx = ip + yd * filter->stride;
498 op[filter->r_off] = ip[0];
499 op[filter->g_off] = (nx[0] + ip[xd] + 1) / 2;
500 op[filter->b_off] = nx[xd];
503 op[filter->r_off] = ip[xd];
504 op[filter->g_off] = ip[0];
505 op[filter->b_off] = nx[0];
508 op[filter->r_off] = nx[0];
509 op[filter->g_off] = ip[0];
510 op[filter->b_off] = ip[xd];
513 op[filter->r_off] = nx[xd];
514 op[filter->g_off] = (nx[0] + ip[xd] + 1) / 2;
515 op[filter->b_off] = ip[0];
521 do_corners (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
526 corner (input, output, 0, 0, 1, 1, BLUE, filter);
528 corner (input, output, 0, filter->height - 1, 1, -1,
529 (filter->height & 1) ? BLUE : GREENR, filter);
531 corner (input, output, filter->width - 1, 0, -1, 0,
532 (filter->width & 1) ? BLUE : GREENB, filter);
534 if (filter->width & 1) /* if odd # cols, B or GB */
537 typ = GREENB; /* if even # cols, B or GR */
538 typ |= (filter->height & 1); /* if odd # rows, GB or GR */
539 corner (input, output, filter->width - 1, filter->height - 1, -1, -1,
544 do_body (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
546 int ip, op; /* input and output pointers */
547 int w, h; /* loop indices */
548 int type; /* calculated colour of current element */
553 * We are processing row (line) by row, starting with the second
554 * row and continuing through the next to last. Each row is processed
555 * column by column, starting with the second and continuing through
556 * to the next to last.
558 for (h = 1; h < filter->height - 1; h++) {
560 * Remember we are processing "row by row". For each row, we need
561 * to set the type of the first element to be processed. Since we
562 * have already processed the edges, the "first element" will be
563 * the pixel at position (1,1). Assuming BG format, this should
564 * be RED for odd-numbered rows and GREENB for even rows.
570 /* Calculate the starting position for the row */
571 op = h * filter->width * filter->pixsize; /* output (converted) pos */
572 ip = h * filter->stride; /* input (bayer data) pos */
573 for (w = 1; w < filter->width - 1; w++) {
574 op += filter->pixsize; /* we are processing "horizontally" */
578 output[op + filter->r_off] = input[ip];
579 output[op + filter->b_off] = (input[ip - filter->stride - 1] +
580 input[ip - filter->stride + 1] +
581 input[ip + filter->stride - 1] +
582 input[ip + filter->stride + 1] + 2) / 4;
583 v1 = input[ip + filter->stride];
584 v2 = input[ip - filter->stride];
590 output[op + filter->g_off] = (v1 + v2 + 1) / 2;
592 output[op + filter->g_off] = (h1 + h2 + 1) / 2;
594 output[op + filter->g_off] = (v1 + h1 + v2 + h2 + 2) / 4;
598 output[op + filter->r_off] = (input[ip + 1] + input[ip - 1] + 1) / 2;
599 output[op + filter->g_off] = input[ip];
600 output[op + filter->b_off] = (input[ip - filter->stride] +
601 input[ip + filter->stride] + 1) / 2;
605 output[op + filter->r_off] = (input[ip - filter->stride] +
606 input[ip + filter->stride] + 1) / 2;
607 output[op + filter->g_off] = input[ip];
608 output[op + filter->b_off] = (input[ip + 1] + input[ip - 1] + 1) / 2;
612 output[op + filter->r_off] = (input[ip - filter->stride - 1] +
613 input[ip - filter->stride + 1] +
614 input[ip + filter->stride - 1] +
615 input[ip + filter->stride + 1] + 2) / 4;
616 output[op + filter->b_off] = input[ip];
617 v1 = input[ip + filter->stride];
618 v2 = input[ip - filter->stride];
624 output[op + filter->g_off] = (v1 + v2 + 1) / 2;
626 output[op + filter->g_off] = (h1 + h2 + 1) / 2;
628 output[op + filter->g_off] = (v1 + h1 + v2 + h2 + 2) / 4;
637 gst_bayer2rgb_transform (GstBaseTransform * base, GstBuffer * inbuf,
640 GstBayer2RGB *filter = GST_BAYER2RGB (base);
641 uint8_t *input, *output;
644 * We need to lock our filter params to prevent changing
645 * caps in the middle of a transformation (nice way to get
648 GST_OBJECT_LOCK (filter);
650 GST_DEBUG ("transforming buffer");
651 input = (uint8_t *) GST_BUFFER_DATA (inbuf);
652 output = (uint8_t *) GST_BUFFER_DATA (outbuf);
653 do_corners (input, output, filter);
654 do_row0_col0 (input, output, filter);
655 do_body (input, output, filter);
657 GST_OBJECT_UNLOCK (filter);