For testing purpose. Used to test XYZ JPEG2000 output
---
libavfilter/Makefile | 1 +
libavfilter/allfilters.c | 1 +
libavfilter/vf_xyz2rgb.c | 201 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 203 insertions(+)
create mode 100644 libavfilter/vf_xyz2rgb.c
diff --git a/libavfilter/Makefile b/libavfilter/Makefile
index 4a3331a..816c640 100644
--- a/libavfilter/Makefile
+++ b/libavfilter/Makefile
@@ -77,6 +77,7 @@ OBJS-$(CONFIG_SPLIT_FILTER) += split.o
OBJS-$(CONFIG_TRANSPOSE_FILTER) += vf_transpose.o
OBJS-$(CONFIG_UNSHARP_FILTER) += vf_unsharp.o
OBJS-$(CONFIG_VFLIP_FILTER) += vf_vflip.o
+OBJS-$(CONFIG_XYZ2RGB_FILTER) += vf_xyz2rgb.o
OBJS-$(CONFIG_YADIF_FILTER) += vf_yadif.o
OBJS-$(CONFIG_COLOR_FILTER) += vsrc_color.o
diff --git a/libavfilter/allfilters.c b/libavfilter/allfilters.c
index f3ce91c..d1021b1 100644
--- a/libavfilter/allfilters.c
+++ b/libavfilter/allfilters.c
@@ -97,6 +97,7 @@ void avfilter_register_all(void)
REGISTER_FILTER(TRANSPOSE, transpose, vf);
REGISTER_FILTER(UNSHARP, unsharp, vf);
REGISTER_FILTER(VFLIP, vflip, vf);
+ REGISTER_FILTER(XYZ2RGB, xyz2rgb, vf);
REGISTER_FILTER(YADIF, yadif, vf);
REGISTER_FILTER(COLOR, color, vsrc);
diff --git a/libavfilter/vf_xyz2rgb.c b/libavfilter/vf_xyz2rgb.c
new file mode 100644
index 0000000..866daa0
--- /dev/null
+++ b/libavfilter/vf_xyz2rgb.c
@@ -0,0 +1,201 @@
+/*
+ * XYZ to RGB filter
+ * Copyright (c) 2012 Matthias Buercher
+ * Copyright (c) 2013 Nicolas Bertrand <[email protected]>
+ *
+ * This file is part of Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * xyz2rgb filter
+ * Converts from XYZ to RGB space
+ * Useful to convert jpeg2000 files from MXF containers in DCP
+ * The filter has no parameters
+ */
+
+#include <string.h>
+
+#include "libavutil/pixdesc.h"
+#include "libavutil/common.h"
+#include "libavutil/internal.h"
+#include "libavutil/intreadwrite.h"
+#include "libavutil/imgutils.h"
+#include "avfilter.h"
+#include "formats.h"
+#include "internal.h"
+#include "video.h"
+
+/* pre defined color-spaces gamma */
+#define XYZ_GAMMA (2.6f)
+#define RGB_GAMMA (2.2f)
+
+typedef struct {
+ int xyzgamma[4096];
+ int rgbgamma[4096];
+ int (* matrix)[3];
+} XYZ2RGBContext;
+
+/*
+ * XYZ to RGB conversion matrix
+ * R | 3.2404542 -1.5371385 -0.4985314 | X
+ * G = 4095 * | -0.9692660 1.8760108 0.0415560 | Y
+ * B | 0.0556434 -0.2040259 1.0572252 | Z
+ *
+ * The matrix is stored in int values
+ */
+static int xyz2rgb_matrix[3][3] = {
+ {13270, -6295, -2041},
+ {-3969, 7682, 170},
+ { 228, -835, 4329} };
+
+static int query_formats(AVFilterContext * ctx)
+{
+ AVFilterFormats *formats;
+ int ret = -1 ;
+
+ if (ctx->inputs[0]) {
+ formats = NULL;
+ ret = ff_add_format(&formats, AV_PIX_FMT_XYZ12);
+ ff_formats_ref(formats, &ctx->inputs[0]->out_formats);
+ }
+ if (ctx->outputs[0]) {
+ formats = NULL;
+ ret = ff_add_format(&formats, AV_PIX_FMT_RGB48);
+ ff_formats_ref(formats, &ctx->outputs[0]->in_formats);
+ }
+ return ret;
+}
+
+/**
+ * The gamma values are precalculated in an array
+ * XYZ uses projector gamma 2.6
+ * sRGB uses gamma 2.2
+ * The gamma function is the inverse power function, calculated in [0..1] and
scaled to 12-bit fixed point
+ *
+ * The matrix multipliers are precalculated and scaled to 12bit bitdepth (4096
values)
+ * For documentation see
+ * http://www.brucelindbloom.com/index.html?Eqn_RGB_XYZ_Matrix.html
+ * http://en.wikipedia.org/wiki/SRGB
+*/
+
+static int config_props(AVFilterLink * inlink)
+{
+ XYZ2RGBContext *settings = inlink->dst->priv;
+ int i;
+ double xyzgamma = XYZ_GAMMA;
+ double rgbgamma = 1.0 / RGB_GAMMA;
+
+ /* set gamma vectors */
+ for (i = 0; i < 4096; i++) {
+ settings->xyzgamma[i] =
+ lrintf(pow(i / 4095.0, xyzgamma) * 4095.0);
+ settings->rgbgamma[i] =
+ lrintf(pow(i / 4095.0, rgbgamma) * 4095.0);
+ }
+
+ settings->matrix = xyz2rgb_matrix;
+ return 0;
+}
+
+static int filter_frame(AVFilterLink * inlink, AVFrame * in)
+{
+ AVFilterLink *outlink = inlink->dst->outputs[0];
+ XYZ2RGBContext *settings = inlink->dst->priv;
+
+ AVFrame *out;
+ uint8_t *inrow, *outrow;
+ int i, j;
+ int r, g, b, x, y, z;
+
+ out = ff_get_video_buffer(outlink, outlink->w, outlink->h);
+ if (!out) {
+ av_frame_free(&in);
+ return AVERROR(ENOMEM);
+ }
+
+ out->pts = in->pts;
+ inrow = in->data[0];
+ outrow = out->data[0];
+
+ /*
+ * In case of XYZ (12-bit depth) format input
+ * conversion to RGB24 (8-bit depth) --> loss of precision
+ * FIXME: test/implement output RGB48 for display
+ */
+ if (inlink->format == AV_PIX_FMT_XYZ12) {
+ for (i = 0; i < inlink->h; i++) {
+ for (j = 0; j < inlink->w * 6; j += 6) {
+ // read little endian and scale from 16bit to 12bit
+ x = AV_RL16(inrow + j) >> 4;
+ y = AV_RL16(inrow + j + 2) >> 4;
+ z = AV_RL16(inrow + j + 4) >> 4;
+
+ // convert from XYZ to XYZlinear
+ x = settings->xyzgamma[x];
+ y = settings->xyzgamma[y];
+ z = settings->xyzgamma[z];
+
+ // convert from XYZlinear to sRGBlinear
+ r = settings->matrix[0][0] * x +
+ settings->matrix[0][1] * y +
+ settings->matrix[0][2] * z >> 12;
+ g = settings->matrix[1][0] * x +
+ settings->matrix[1][1] * y +
+ settings->matrix[1][2] * z >> 12;
+ b = settings->matrix[2][0] * x +
+ settings->matrix[1][2] * y +
+ settings->matrix[2][2] * z >> 12;
+
+ // limit values to 12-bit depth
+ r = av_clip_c(r,0,4095);
+ g = av_clip_c(g,0,4095);
+ b = av_clip_c(b,0,4095);
+
+ // convert from sRGBlinear to RGB and scale from 12bit to 16bit
+ r = settings->rgbgamma[r] << 4;
+ g = settings->rgbgamma[g] << 4;
+ b = settings->rgbgamma[b] << 4;
+
+ // write little endian
+ AV_WL16(outrow + j, r);
+ AV_WL16(outrow + j + 2, g);
+ AV_WL16(outrow + j + 4, b);
+ }
+ inrow += in->linesize[0];
+ outrow += out->linesize[0];
+ }
+ }
+ av_frame_free(&in);
+ return ff_filter_frame(outlink, out);
+}
+
+AVFilter avfilter_vf_xyz2rgb = {
+ .name = "xyz2rgb",
+ .description = NULL_IF_CONFIG_SMALL("Converts XYZ to RGB."),
+ .priv_size = sizeof(XYZ2RGBContext),
+ .query_formats = query_formats,
+ .inputs = (const AVFilterPad[]) {{.name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,
+ .filter_frame = filter_frame,
+ .config_props = config_props,
+ .min_perms = AV_PERM_READ,},
+ {.name = NULL}},
+ .outputs = (const AVFilterPad[]) {{.name = "default",
+ .type = AVMEDIA_TYPE_VIDEO,},
+ {.name = NULL}},
+};
--
1.7.9.5
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