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);
90 GST_BAYER_2_RGB_FORMAT_BGGR = 0,
91 GST_BAYER_2_RGB_FORMAT_GBRG,
92 GST_BAYER_2_RGB_FORMAT_GRBG,
93 GST_BAYER_2_RGB_FORMAT_RGGB
97 #define GST_TYPE_BAYER2RGB (gst_bayer2rgb_get_type())
98 #define GST_BAYER2RGB(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj),GST_TYPE_BAYER2RGB,GstBayer2RGB))
99 #define GST_IS_BAYER2RGB(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj),GST_TYPE_BAYER2RGB))
100 #define GST_BAYER2RGB_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST((klass) ,GST_TYPE_BAYER2RGB,GstBayer2RGBClass))
101 #define GST_IS_BAYER2RGB_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE((klass) ,GST_TYPE_BAYER2RGB))
102 #define GST_BAYER2RGB_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS((obj) ,GST_TYPE_BAYER2RGB,GstBayer2RGBClass))
103 typedef struct _GstBayer2RGB GstBayer2RGB;
104 typedef struct _GstBayer2RGBClass GstBayer2RGBClass;
106 typedef void (*GstBayer2RGBProcessFunc) (GstBayer2RGB *, guint8 *, guint);
110 GstBaseTransform basetransform;
116 int pixsize; /* bytes per pixel */
117 int r_off; /* offset for red */
118 int g_off; /* offset for green */
119 int b_off; /* offset for blue */
123 struct _GstBayer2RGBClass
125 GstBaseTransformClass parent;
128 //#define SRC_CAPS GST_VIDEO_CAPS_RGBx
130 GST_VIDEO_CAPS_RGBx ";" \
131 GST_VIDEO_CAPS_xRGB ";" \
132 GST_VIDEO_CAPS_BGRx ";" \
133 GST_VIDEO_CAPS_xBGR ";" \
134 GST_VIDEO_CAPS_RGBA ";" \
135 GST_VIDEO_CAPS_ARGB ";" \
136 GST_VIDEO_CAPS_BGRA ";" \
137 GST_VIDEO_CAPS_ABGR ";" \
138 GST_VIDEO_CAPS_RGB ";" \
141 #define SINK_CAPS "video/x-raw-bayer,format=(string){bggr,grbg,gbrg,rggb}," \
142 "width=(int)[1,MAX],height=(int)[1,MAX],framerate=(fraction)[0/1,MAX]"
149 #define DEBUG_INIT(bla) \
150 GST_DEBUG_CATEGORY_INIT (gst_bayer2rgb_debug, "bayer2rgb", 0, "bayer2rgb element");
152 GType gst_bayer2rgb_get_type (void);
153 GST_BOILERPLATE_FULL (GstBayer2RGB, gst_bayer2rgb, GstBaseTransform,
154 GST_TYPE_BASE_TRANSFORM, DEBUG_INIT);
156 static void gst_bayer2rgb_set_property (GObject * object, guint prop_id,
157 const GValue * value, GParamSpec * pspec);
158 static void gst_bayer2rgb_get_property (GObject * object, guint prop_id,
159 GValue * value, GParamSpec * pspec);
161 static gboolean gst_bayer2rgb_set_caps (GstBaseTransform * filter,
162 GstCaps * incaps, GstCaps * outcaps);
163 static GstFlowReturn gst_bayer2rgb_transform (GstBaseTransform * base,
164 GstBuffer * inbuf, GstBuffer * outbuf);
165 static void gst_bayer2rgb_reset (GstBayer2RGB * filter);
166 static GstCaps *gst_bayer2rgb_transform_caps (GstBaseTransform * base,
167 GstPadDirection direction, GstCaps * caps);
168 static gboolean gst_bayer2rgb_get_unit_size (GstBaseTransform * base,
169 GstCaps * caps, guint * size);
173 gst_bayer2rgb_base_init (gpointer klass)
175 GstElementClass *element_class = GST_ELEMENT_CLASS (klass);
177 gst_element_class_set_details_simple (element_class,
178 "Bayer to RGB decoder for cameras", "Filter/Converter/Video",
179 "Converts video/x-raw-bayer to video/x-raw-rgb",
180 "William Brack <wbrack@mmm.com.hk>");
182 gst_element_class_add_pad_template (element_class,
183 gst_pad_template_new ("src", GST_PAD_SRC, GST_PAD_ALWAYS,
184 gst_caps_from_string (SRC_CAPS)));
185 gst_element_class_add_pad_template (element_class,
186 gst_pad_template_new ("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
187 gst_caps_from_string (SINK_CAPS)));
191 gst_bayer2rgb_class_init (GstBayer2RGBClass * klass)
193 GObjectClass *gobject_class;
195 gobject_class = (GObjectClass *) klass;
196 gobject_class->set_property = gst_bayer2rgb_set_property;
197 gobject_class->get_property = gst_bayer2rgb_get_property;
199 GST_BASE_TRANSFORM_CLASS (klass)->transform_caps =
200 GST_DEBUG_FUNCPTR (gst_bayer2rgb_transform_caps);
201 GST_BASE_TRANSFORM_CLASS (klass)->get_unit_size =
202 GST_DEBUG_FUNCPTR (gst_bayer2rgb_get_unit_size);
203 GST_BASE_TRANSFORM_CLASS (klass)->set_caps =
204 GST_DEBUG_FUNCPTR (gst_bayer2rgb_set_caps);
205 GST_BASE_TRANSFORM_CLASS (klass)->transform =
206 GST_DEBUG_FUNCPTR (gst_bayer2rgb_transform);
210 gst_bayer2rgb_init (GstBayer2RGB * filter, GstBayer2RGBClass * klass)
212 gst_bayer2rgb_reset (filter);
213 gst_base_transform_set_in_place (GST_BASE_TRANSFORM (filter), TRUE);
216 /* No properties are implemented, so only a warning is produced */
218 gst_bayer2rgb_set_property (GObject * object, guint prop_id,
219 const GValue * value, GParamSpec * pspec)
224 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
230 gst_bayer2rgb_get_property (GObject * object, guint prop_id,
231 GValue * value, GParamSpec * pspec)
236 G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
241 /* Routine to convert colormask value into relative byte offset */
243 get_pix_offset (int mask, int bpp)
245 int bpp32 = (bpp / 8) - 3;
257 GST_ERROR ("Invalid color mask 0x%08x", mask);
263 gst_bayer2rgb_set_caps (GstBaseTransform * base, GstCaps * incaps,
266 GstBayer2RGB *bayer2rgb = GST_BAYER2RGB (base);
267 GstStructure *structure;
271 GST_DEBUG ("in caps %" GST_PTR_FORMAT " out caps %" GST_PTR_FORMAT, incaps,
274 structure = gst_caps_get_structure (incaps, 0);
276 gst_structure_get_int (structure, "width", &bayer2rgb->width);
277 gst_structure_get_int (structure, "height", &bayer2rgb->height);
278 bayer2rgb->stride = GST_ROUND_UP_4 (bayer2rgb->width);
280 format = gst_structure_get_string (structure, "format");
281 if (g_str_equal (format, "bggr")) {
282 bayer2rgb->format = GST_BAYER_2_RGB_FORMAT_BGGR;
283 } else if (g_str_equal (format, "gbrg")) {
284 bayer2rgb->format = GST_BAYER_2_RGB_FORMAT_GBRG;
285 } else if (g_str_equal (format, "grbg")) {
286 bayer2rgb->format = GST_BAYER_2_RGB_FORMAT_GRBG;
287 } else if (g_str_equal (format, "rggb")) {
288 bayer2rgb->format = GST_BAYER_2_RGB_FORMAT_RGGB;
293 /* To cater for different RGB formats, we need to set params for later */
294 structure = gst_caps_get_structure (outcaps, 0);
295 gst_structure_get_int (structure, "bpp", &bpp);
296 bayer2rgb->pixsize = bpp / 8;
297 gst_structure_get_int (structure, "red_mask", &val);
298 bayer2rgb->r_off = get_pix_offset (val, bpp);
299 gst_structure_get_int (structure, "green_mask", &val);
300 bayer2rgb->g_off = get_pix_offset (val, bpp);
301 gst_structure_get_int (structure, "blue_mask", &val);
302 bayer2rgb->b_off = get_pix_offset (val, bpp);
308 gst_bayer2rgb_reset (GstBayer2RGB * filter)
320 gst_bayer2rgb_transform_caps (GstBaseTransform * base,
321 GstPadDirection direction, GstCaps * caps)
323 GstStructure *structure;
325 GstStructure *newstruct;
327 GST_DEBUG_OBJECT (caps, "transforming caps (from)");
329 structure = gst_caps_get_structure (caps, 0);
331 if (direction == GST_PAD_SRC) {
332 newcaps = gst_caps_from_string ("video/x-raw-bayer,"
333 "format=(string){bggr,grbg,gbrg,rggb}");
335 newcaps = gst_caps_new_simple ("video/x-raw-rgb", NULL);
337 newstruct = gst_caps_get_structure (newcaps, 0);
339 gst_structure_set_value (newstruct, "width",
340 gst_structure_get_value (structure, "width"));
341 gst_structure_set_value (newstruct, "height",
342 gst_structure_get_value (structure, "height"));
343 gst_structure_set_value (newstruct, "framerate",
344 gst_structure_get_value (structure, "framerate"));
346 GST_DEBUG_OBJECT (newcaps, "transforming caps (into)");
352 gst_bayer2rgb_get_unit_size (GstBaseTransform * base, GstCaps * caps,
355 GstStructure *structure;
361 structure = gst_caps_get_structure (caps, 0);
363 if (gst_structure_get_int (structure, "width", &width) &&
364 gst_structure_get_int (structure, "height", &height)) {
365 name = gst_structure_get_name (structure);
366 /* Our name must be either video/x-raw-bayer video/x-raw-rgb */
367 if (strcmp (name, "video/x-raw-rgb")) {
368 /* For bayer, we handle only BA81 (BGGR), which is BPP=24 */
369 *size = GST_ROUND_UP_4 (width) * height;
372 /* For output, calculate according to format */
373 if (gst_structure_get_int (structure, "bpp", &pixsize)) {
374 *size = width * height * (pixsize / 8);
380 GST_ELEMENT_ERROR (base, CORE, NEGOTIATION, (NULL),
381 ("Incomplete caps, some required field missing"));
386 * We define values for the colors, just to make the code more readable.
388 #define RED 0 /* Pure red element */
389 #define GREENB 1 /* Green element which is on a blue line */
390 #define BLUE 2 /* Pure blue element */
391 #define GREENR 3 /* Green element which is on a red line */
394 get_pixel_type (GstBayer2RGB * filter, int x, int y)
398 if (((x ^ filter->format) & 1)) {
399 if ((y ^ (filter->format >> 1)) & 1)
404 if ((y ^ (filter->format >> 1)) & 1)
412 /* Routine to generate the top and bottom edges (not including corners) */
414 hborder (uint8_t * input, uint8_t * output, int bot_top,
415 int typ, GstBayer2RGB * filter)
417 uint8_t *op; /* output pointer */
418 uint8_t *ip; /* input pointer */
419 uint8_t *nx; /* next line pointer */
420 int ix; /* loop index */
422 op = output + (bot_top * filter->width * (filter->height - 1) + 1) *
424 ip = input + bot_top * filter->stride * (filter->height - 1);
425 /* calculate minus or plus one line, depending upon bot_top flag */
426 nx = ip + (1 - 2 * bot_top) * filter->stride;
427 /* Stepping horizontally */
428 for (ix = 1; ix < filter->width - 1; ix++, op += filter->pixsize) {
431 op[filter->r_off] = ip[ix];
432 op[filter->g_off] = (ip[ix + 1] + ip[ix - 1] + nx[ix] + 1) / 3;
433 op[filter->b_off] = (nx[ix + 1] + nx[ix - 1] + 1) / 2;
437 op[filter->r_off] = (ip[ix + 1] + ip[ix - 1] + 1) / 2;
438 op[filter->g_off] = ip[ix];
439 op[filter->b_off] = nx[ix];
443 op[filter->r_off] = nx[ix];
444 op[filter->g_off] = ip[ix];
445 op[filter->b_off] = (ip[ix + 1] + ip[ix - 1] + 1) / 2;
449 op[filter->r_off] = (nx[ix + 1] + nx[ix - 1] + 1) / 2;
450 op[filter->g_off] = (ip[ix + 1] + ip[ix - 1] + nx[ix] + 1) / 3;
451 op[filter->b_off] = ip[ix];
458 /* Routine to generate the left and right edges, not including corners */
460 vborder (uint8_t * input, uint8_t * output, int right_left,
461 int typ, GstBayer2RGB * filter)
463 uint8_t *op; /* output pointer */
464 uint8_t *ip; /* input pointer */
465 uint8_t *la; /* line above pointer */
466 uint8_t *lb; /* line below pointer */
467 int ix; /* loop index */
468 int lr; /* 'left-right' flag - +1 is right, -1 is left */
470 lr = (1 - 2 * right_left);
471 /* stepping vertically */
472 for (ix = 1; ix < filter->height - 1; ix++) {
473 ip = input + right_left * (filter->width - 1) + ix * filter->stride;
474 op = output + (right_left * (filter->width - 1) + ix * filter->width) *
476 la = ip + filter->stride;
477 lb = ip - filter->stride;
480 op[filter->r_off] = ip[0];
481 op[filter->g_off] = (la[0] + ip[lr] + lb[0] + 1) / 3;
482 op[filter->b_off] = (la[lr] + lb[lr] + 1) / 2;
486 op[filter->r_off] = ip[lr];
487 op[filter->g_off] = ip[0];
488 op[filter->b_off] = (la[lr] + lb[lr] + 1) / 2;
492 op[filter->r_off] = (la[lr] + lb[lr] + 1) / 2;
493 op[filter->g_off] = ip[0];
494 op[filter->b_off] = ip[lr];
498 op[filter->r_off] = (la[lr] + lb[lr] + 1) / 2;
499 op[filter->g_off] = (la[0] + ip[lr] + lb[0] + 1) / 3;
500 op[filter->b_off] = ip[0];
507 /* Produce the four (top, bottom, left, right) edges */
509 do_row0_col0 (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
511 /* Horizontal edges */
512 hborder (input, output, 0, get_pixel_type (filter, 1, 0), filter);
513 hborder (input, output, 1, get_pixel_type (filter, 1, filter->height - 1),
517 vborder (input, output, 0, get_pixel_type (filter, 0, 1), filter);
518 vborder (input, output, 1, get_pixel_type (filter, filter->width - 1, 1),
523 corner (uint8_t * input, uint8_t * output, int x, int y,
524 int xd, int yd, int typ, GstBayer2RGB * filter)
526 uint8_t *ip; /* input pointer */
527 uint8_t *op; /* output pointer */
528 uint8_t *nx; /* adjacent line */
530 op = output + y * filter->width * filter->pixsize + x * filter->pixsize;
531 ip = input + y * filter->stride + x;
532 nx = ip + yd * filter->stride;
535 op[filter->r_off] = ip[0];
536 op[filter->g_off] = (nx[0] + ip[xd] + 1) / 2;
537 op[filter->b_off] = nx[xd];
540 op[filter->r_off] = ip[xd];
541 op[filter->g_off] = ip[0];
542 op[filter->b_off] = nx[0];
545 op[filter->r_off] = nx[0];
546 op[filter->g_off] = ip[0];
547 op[filter->b_off] = ip[xd];
550 op[filter->r_off] = nx[xd];
551 op[filter->g_off] = (nx[0] + ip[xd] + 1) / 2;
552 op[filter->b_off] = ip[0];
558 do_corners (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
561 corner (input, output, 0, 0, 1, 1, get_pixel_type (filter, 0, 0), filter);
563 corner (input, output, 0, filter->height - 1, 1, -1,
564 get_pixel_type (filter, 0, filter->height - 1), filter);
566 corner (input, output, filter->width - 1, 0, -1, 0,
567 get_pixel_type (filter, filter->width - 1, 0), filter);
569 corner (input, output, filter->width - 1, filter->height - 1, -1, -1,
570 get_pixel_type (filter, filter->width - 1, filter->height - 1), filter);
574 do_body (uint8_t * input, uint8_t * output, GstBayer2RGB * filter)
576 int ip, op; /* input and output pointers */
577 int w, h; /* loop indices */
578 int type; /* calculated colour of current element */
583 * We are processing row (line) by row, starting with the second
584 * row and continuing through the next to last. Each row is processed
585 * column by column, starting with the second and continuing through
586 * to the next to last.
588 for (h = 1; h < filter->height - 1; h++) {
590 * Remember we are processing "row by row". For each row, we need
591 * to set the type of the first element to be processed. Since we
592 * have already processed the edges, the "first element" will be
593 * the pixel at position (1,1). Assuming BG format, this should
594 * be RED for odd-numbered rows and GREENB for even rows.
596 type = get_pixel_type (filter, 1, h);
597 /* Calculate the starting position for the row */
598 op = h * filter->width * filter->pixsize; /* output (converted) pos */
599 ip = h * filter->stride; /* input (bayer data) pos */
600 for (w = 1; w < filter->width - 1; w++) {
601 op += filter->pixsize; /* we are processing "horizontally" */
605 output[op + filter->r_off] = input[ip];
606 output[op + filter->b_off] = (input[ip - filter->stride - 1] +
607 input[ip - filter->stride + 1] +
608 input[ip + filter->stride - 1] +
609 input[ip + filter->stride + 1] + 2) / 4;
610 v1 = input[ip + filter->stride];
611 v2 = input[ip - filter->stride];
617 output[op + filter->g_off] = (v1 + v2 + 1) / 2;
619 output[op + filter->g_off] = (h1 + h2 + 1) / 2;
621 output[op + filter->g_off] = (v1 + h1 + v2 + h2 + 2) / 4;
625 output[op + filter->r_off] = (input[ip + 1] + input[ip - 1] + 1) / 2;
626 output[op + filter->g_off] = input[ip];
627 output[op + filter->b_off] = (input[ip - filter->stride] +
628 input[ip + filter->stride] + 1) / 2;
632 output[op + filter->r_off] = (input[ip - filter->stride] +
633 input[ip + filter->stride] + 1) / 2;
634 output[op + filter->g_off] = input[ip];
635 output[op + filter->b_off] = (input[ip + 1] + input[ip - 1] + 1) / 2;
639 output[op + filter->r_off] = (input[ip - filter->stride - 1] +
640 input[ip - filter->stride + 1] +
641 input[ip + filter->stride - 1] +
642 input[ip + filter->stride + 1] + 2) / 4;
643 output[op + filter->b_off] = input[ip];
644 v1 = input[ip + filter->stride];
645 v2 = input[ip - filter->stride];
651 output[op + filter->g_off] = (v1 + v2 + 1) / 2;
653 output[op + filter->g_off] = (h1 + h2 + 1) / 2;
655 output[op + filter->g_off] = (v1 + h1 + v2 + h2 + 2) / 4;
664 gst_bayer2rgb_transform (GstBaseTransform * base, GstBuffer * inbuf,
667 GstBayer2RGB *filter = GST_BAYER2RGB (base);
668 uint8_t *input, *output;
671 * We need to lock our filter params to prevent changing
672 * caps in the middle of a transformation (nice way to get
675 GST_OBJECT_LOCK (filter);
677 GST_DEBUG ("transforming buffer");
678 input = (uint8_t *) GST_BUFFER_DATA (inbuf);
679 output = (uint8_t *) GST_BUFFER_DATA (outbuf);
680 do_corners (input, output, filter);
681 do_row0_col0 (input, output, filter);
682 do_body (input, output, filter);
684 GST_OBJECT_UNLOCK (filter);