[FFmpeg-cvslog] libavfilter: image transform code
danielgtaylor
git at videolan.org
Tue Oct 4 02:29:50 CEST 2011
ffmpeg | branch: master | danielgtaylor <dan at programmer-art.org> | Tue Oct 4 02:10:18 2011 +0200| [7985381e236a95c711a5315a83c891eef0c56d3b] | committer: Michael Niedermayer
libavfilter: image transform code
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7985381e236a95c711a5315a83c891eef0c56d3b
---
libavfilter/transform.c | 182 +++++++++++++++++++++++++++++++++++++++++++++++
libavfilter/transform.h | 125 ++++++++++++++++++++++++++++++++
2 files changed, 307 insertions(+), 0 deletions(-)
diff --git a/libavfilter/transform.c b/libavfilter/transform.c
new file mode 100644
index 0000000..c3f7939
--- /dev/null
+++ b/libavfilter/transform.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2010 Georg Martius <georg.martius at web.de>
+ * Copyright (C) 2010 Daniel G. Taylor <dan at programmer-art.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavfilter/transform.c
+ * transform input video
+ */
+
+#include "libavutil/common.h"
+
+#include "transform.h"
+
+#define INTERPOLATE_METHOD(name) \
+ static uint8_t name(float x, float y, const uint8_t *src, \
+ int width, int height, int stride, uint8_t def)
+
+#define PIXEL(img, x, y, w, h, stride, def) \
+ ((x) < 0 || (y) < 0) ? (def) : \
+ (((x) >= (w) || (y) >= (h)) ? (def) : \
+ img[(x) + (y) * (stride)])
+
+/**
+ * Nearest neighbor interpolation
+ */
+INTERPOLATE_METHOD(interpolate_nearest)
+{
+ return PIXEL(src, (int)(x + 0.5), (int)(y + 0.5), width, height, stride, def);
+}
+
+/**
+ * Bilinear interpolation
+ */
+INTERPOLATE_METHOD(interpolate_bilinear)
+{
+ int x_c, x_f, y_c, y_f;
+ int v1, v2, v3, v4;
+
+ if (x < -1 || x > width || y < -1 || y > height) {
+ return def;
+ } else {
+ x_f = (int)x;
+ x_c = x_f + 1;
+
+ y_f = (int)y;
+ y_c = y_f + 1;
+
+ v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
+ v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
+ v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
+ v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
+
+ return (v1*(x - x_f)*(y - y_f) + v2*((x - x_f)*(y_c - y)) +
+ v3*(x_c - x)*(y - y_f) + v4*((x_c - x)*(y_c - y)));
+ }
+}
+
+/**
+ * Biquadratic interpolation
+ */
+INTERPOLATE_METHOD(interpolate_biquadratic)
+{
+ int x_c, x_f, y_c, y_f;
+ uint8_t v1, v2, v3, v4;
+ float f1, f2, f3, f4;
+
+ if (x < - 1 || x > width || y < -1 || y > height)
+ return def;
+ else {
+ x_f = (int)x;
+ x_c = x_f + 1;
+ y_f = (int)y;
+ y_c = y_f + 1;
+
+ v1 = PIXEL(src, x_c, y_c, width, height, stride, def);
+ v2 = PIXEL(src, x_c, y_f, width, height, stride, def);
+ v3 = PIXEL(src, x_f, y_c, width, height, stride, def);
+ v4 = PIXEL(src, x_f, y_f, width, height, stride, def);
+
+ f1 = 1 - sqrt((x_c - x) * (y_c - y));
+ f2 = 1 - sqrt((x_c - x) * (y - y_f));
+ f3 = 1 - sqrt((x - x_f) * (y_c - y));
+ f4 = 1 - sqrt((x - x_f) * (y - y_f));
+ return (v1 * f1 + v2 * f2 + v3 * f3 + v4 * f4) / (f1 + f2 + f3 + f4);
+ }
+}
+
+void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix) {
+ matrix[0] = zoom * cos(angle);
+ matrix[1] = -sin(angle);
+ matrix[2] = x_shift;
+ matrix[3] = -matrix[1];
+ matrix[4] = matrix[0];
+ matrix[5] = y_shift;
+ matrix[6] = 0;
+ matrix[7] = 0;
+ matrix[8] = 1;
+}
+
+void avfilter_add_matrix(const float *m1, const float *m2, float *result)
+{
+ for (int i = 0; i < 9; i++)
+ result[i] = m1[i] + m2[i];
+}
+
+void avfilter_sub_matrix(const float *m1, const float *m2, float *result)
+{
+ for (int i = 0; i < 9; i++)
+ result[i] = m1[i] - m2[i];
+}
+
+void avfilter_mul_matrix(const float *m1, float scalar, float *result)
+{
+ for (int i = 0; i < 9; i++)
+ result[i] = m1[i] * scalar;
+}
+
+void avfilter_transform(const uint8_t *src, uint8_t *dst,
+ int src_stride, int dst_stride,
+ int width, int height, const float *matrix,
+ enum InterpolateMethod interpolate,
+ enum FillMethod fill)
+{
+ int x, y;
+ float x_s, y_s;
+ uint8_t def = 0;
+ uint8_t (*func)(float, float, const uint8_t *, int, int, int, uint8_t) = NULL;
+
+ switch(interpolate) {
+ case INTERPOLATE_NEAREST:
+ func = interpolate_nearest;
+ break;
+ case INTERPOLATE_BILINEAR:
+ func = interpolate_bilinear;
+ break;
+ case INTERPOLATE_BIQUADRATIC:
+ func = interpolate_biquadratic;
+ break;
+ }
+
+ for (y = 0; y < height; y++) {
+ for(x = 0; x < width; x++) {
+ x_s = x * matrix[0] + y * matrix[1] + matrix[2];
+ y_s = x * matrix[3] + y * matrix[4] + matrix[5];
+
+ switch(fill) {
+ case FILL_ORIGINAL:
+ def = src[y * src_stride + x];
+ break;
+ case FILL_CLAMP:
+ y_s = av_clipf(y_s, 0, height - 1);
+ x_s = av_clipf(x_s, 0, width - 1);
+ def = src[(int)y_s * src_stride + (int)x_s];
+ break;
+ case FILL_MIRROR:
+ y_s = (y_s < 0) ? -y_s : (y_s >= height) ? (height + height - y_s) : y_s;
+ x_s = (x_s < 0) ? -x_s : (x_s >= width) ? (width + width - x_s) : x_s;
+ def = src[(int)y_s * src_stride + (int)x_s];
+ }
+
+ dst[y * dst_stride + x] = func(x_s, y_s, src, width, height, src_stride, def);
+ }
+ }
+}
+
diff --git a/libavfilter/transform.h b/libavfilter/transform.h
new file mode 100644
index 0000000..2d5cf37
--- /dev/null
+++ b/libavfilter/transform.h
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2010 Georg Martius <georg.martius at web.de>
+ * Copyright (C) 2010 Daniel G. Taylor <dan at programmer-art.org>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg 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.
+ *
+ * FFmpeg 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file libavfilter/transform.h
+ * transform input video
+ *
+ * All matrices are defined as a single 9-item block of contiguous memory. For
+ * example, the identity matrix would be:
+ *
+ * float *matrix = {1, 0, 0,
+ * 0, 1, 0,
+ * 0, 0, 1};
+ */
+
+enum InterpolateMethod {
+ INTERPOLATE_NEAREST, //< Nearest-neighbor (fast)
+ INTERPOLATE_BILINEAR, //< Bilinear
+ INTERPOLATE_BIQUADRATIC, //< Biquadratic (best)
+ INTERPOLATE_COUNT, //< Number of interpolation methods
+};
+
+// Shortcuts for the fastest and best interpolation methods
+#define INTERPOLATE_DEFAULT INTERPOLATE_BILINEAR
+#define INTERPOLATE_FAST INTERPOLATE_NEAREST
+#define INTERPOLATE_BEST INTERPOLATE_BIQUADRATIC
+
+enum FillMethod {
+ FILL_BLANK, //< Fill zeroes at blank locations
+ FILL_ORIGINAL, //< Original image at blank locations
+ FILL_CLAMP, //< Extruded edge value at blank locations
+ FILL_MIRROR, //< Mirrored edge at blank locations
+ FILL_COUNT, //< Number of edge fill methods
+};
+
+// Shortcuts for fill methods
+#define FILL_DEFAULT FILL_ORIGINAL
+
+/**
+ * Get an affine transformation matrix from a given translation, rotation, and
+ * zoom factor. The matrix will look like:
+ *
+ * [ zoom * cos(angle), -sin(angle), x_shift,
+ * sin(angle), zoom * cos(angle), y_shift,
+ 0, 0, 1 ]
+ *
+ * Paramters:
+ * x_shift: Horizontal translation
+ * y_shift: Vertical translation
+ * angle: Rotation in radians
+ * zoom: Scale percent (1.0 = 100%)
+ * matrix: 9-item affine transformation matrix
+ */
+void avfilter_get_matrix(float x_shift, float y_shift, float angle, float zoom, float *matrix);
+
+/**
+ * Add two matrices together. result = m1 + m2.
+ *
+ * Parameters:
+ * m1: 9-item transformation matrix
+ * m2: 9-item transformation matrix
+ * result: 9-item transformation matrix
+ */
+void avfilter_add_matrix(const float *m1, const float *m2, float *result);
+
+/**
+ * Subtract one matrix from another. result = m1 - m2.
+ *
+ * Parameters:
+ * m1: 9-item transformation matrix
+ * m2: 9-item transformation matrix
+ * result: 9-item transformation matrix
+ */
+void avfilter_sub_matrix(const float *m1, const float *m2, float *result);
+
+/**
+ * Multiply a matrix by a scalar value. result = m1 * scalar.
+ *
+ * Parameters:
+ * m1: 9-item transformation matrix
+ * scalar: A number
+ * result: 9-item transformation matrix
+ */
+void avfilter_mul_matrix(const float *m1, float scalar, float *result);
+
+/**
+ * Do an affine transformation with the given interpolation method. This
+ * multiplies each vector [x,y,1] by the matrix and then interpolates to
+ * get the final value.
+ *
+ * Parameters:
+ * src: Source image
+ * dst: Destination image
+ * src_stride: Source image line size in bytes
+ * dst_stride: Destination image line size in bytes
+ * width: Image width in pixels
+ * height: Image height in pixels
+ * matrix: 9-item affine transformation matrix
+ * interpolate: Pixel interpolation method
+ * fill: Edge fill method
+ */
+void avfilter_transform(const uint8_t *src, uint8_t *dst,
+ int src_stride, int dst_stride,
+ int width, int height, const float *matrix,
+ enum InterpolateMethod interpolate,
+ enum FillMethod fill);
+
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