1/* GStreamer
2 * Copyright (C) <2014> Wim Taymans <wim.taymans@gmail.com>
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
17 * Boston, MA 02110-1301, USA.
18 */
19
20#ifndef __GST_VIDEO_RESAMPLER_H__
21#define __GST_VIDEO_RESAMPLER_H__
22
23#include <gst/gst.h>
24#include <gst/video/video-prelude.h>
25
26G_BEGIN_DECLS
27
28typedef struct _GstVideoResampler GstVideoResampler;
29
30/**
31 * GstVideoResamplerMethod:
32 * @GST_VIDEO_RESAMPLER_METHOD_NEAREST: Duplicates the samples when
33 * upsampling and drops when downsampling
34 * @GST_VIDEO_RESAMPLER_METHOD_LINEAR: Uses linear interpolation to reconstruct
35 * missing samples and averaging to downsample
36 * @GST_VIDEO_RESAMPLER_METHOD_CUBIC: Uses cubic interpolation
37 * @GST_VIDEO_RESAMPLER_METHOD_SINC: Uses sinc interpolation
38 * @GST_VIDEO_RESAMPLER_METHOD_LANCZOS: Uses lanczos interpolation
39 *
40 * Different subsampling and upsampling methods
41 *
42 * Since: 1.6
43 */
44typedef enum {
45 GST_VIDEO_RESAMPLER_METHOD_NEAREST,
46 GST_VIDEO_RESAMPLER_METHOD_LINEAR,
47 GST_VIDEO_RESAMPLER_METHOD_CUBIC,
48 GST_VIDEO_RESAMPLER_METHOD_SINC,
49 GST_VIDEO_RESAMPLER_METHOD_LANCZOS
50} GstVideoResamplerMethod;
51
52/**
53 * GST_VIDEO_RESAMPLER_OPT_CUBIC_B:
54 *
55 * G_TYPE_DOUBLE, B parameter of the cubic filter. The B
56 * parameter controls the bluriness. Values between 0.0 and
57 * 2.0 are accepted. 1/3 is the default.
58 *
59 * Below are some values of popular filters:
60 * B C
61 * Hermite 0.0 0.0
62 * Spline 1.0 0.0
63 * Catmull-Rom 0.0 1/2
64 * Mitchell 1/3 1/3
65 * Robidoux 0.3782 0.3109
66 * Robidoux
67 * Sharp 0.2620 0.3690
68 * Robidoux
69 * Soft 0.6796 0.1602
70 */
71#define GST_VIDEO_RESAMPLER_OPT_CUBIC_B "GstVideoResampler.cubic-b"
72/**
73 * GST_VIDEO_RESAMPLER_OPT_CUBIC_C:
74 *
75 * G_TYPE_DOUBLE, C parameter of the cubic filter. The C
76 * parameter controls the Keys alpha value. Values between 0.0 and
77 * 2.0 are accepted. 1/3 is the default.
78 *
79 * See #GST_VIDEO_RESAMPLER_OPT_CUBIC_B for some more common values
80 */
81#define GST_VIDEO_RESAMPLER_OPT_CUBIC_C "GstVideoResampler.cubic-c"
82
83/**
84 * GST_VIDEO_RESAMPLER_OPT_ENVELOPE:
85 *
86 * G_TYPE_DOUBLE, specifies the size of filter envelope for
87 * @GST_VIDEO_RESAMPLER_METHOD_LANCZOS. values are clamped between
88 * 1.0 and 5.0. 2.0 is the default.
89 */
90#define GST_VIDEO_RESAMPLER_OPT_ENVELOPE "GstVideoResampler.envelope"
91
92/**
93 * GST_VIDEO_RESAMPLER_OPT_SHARPNESS:
94 *
95 * G_TYPE_DOUBLE, specifies sharpness of the filter for
96 * @GST_VIDEO_RESAMPLER_METHOD_LANCZOS. values are clamped between
97 * 0.5 and 1.5. 1.0 is the default.
98 */
99#define GST_VIDEO_RESAMPLER_OPT_SHARPNESS "GstVideoResampler.sharpness"
100
101/**
102 * GST_VIDEO_RESAMPLER_OPT_SHARPEN:
103 *
104 * G_TYPE_DOUBLE, specifies sharpening of the filter for
105 * @GST_VIDEO_RESAMPLER_METHOD_LANCZOS. values are clamped between
106 * 0.0 and 1.0. 0.0 is the default.
107 */
108#define GST_VIDEO_RESAMPLER_OPT_SHARPEN "GstVideoResampler.sharpen"
109/**
110 * GST_VIDEO_RESAMPLER_OPT_MAX_TAPS:
111 *
112 * G_TYPE_INT, limits the maximum number of taps to use.
113 * 16 is the default.
114 */
115#define GST_VIDEO_RESAMPLER_OPT_MAX_TAPS "GstVideoResampler.max-taps"
116
117/**
118 * GstVideoResamplerFlags:
119 * @GST_VIDEO_RESAMPLER_FLAG_NONE: no flags
120 * @GST_VIDEO_RESAMPLER_FLAG_HALF_TAPS: when no taps are given, half the
121 * number of calculated taps. This can be used when making scalers
122 * for the different fields of an interlaced picture. Since: 1.10
123 *
124 * Different resampler flags.
125 *
126 * Since: 1.6
127 */
128typedef enum {
129 GST_VIDEO_RESAMPLER_FLAG_NONE = (0),
130 GST_VIDEO_RESAMPLER_FLAG_HALF_TAPS = (1 << 0),
131} GstVideoResamplerFlags;
132
133/**
134 * GstVideoResampler:
135 * @in_size: the input size
136 * @out_size: the output size
137 * @max_taps: the maximum number of taps
138 * @n_phases: the number of phases
139 * @offset: array with the source offset for each output element
140 * @phase: array with the phase to use for each output element
141 * @n_taps: array with new number of taps for each phase
142 * @taps: the taps for all phases
143 *
144 * A structure holding resampler information.
145 *
146 * Since: 1.6
147 */
148struct _GstVideoResampler
149{
150 gint in_size;
151 gint out_size;
152 guint max_taps;
153 guint n_phases;
154 guint32 *offset;
155 guint32 *phase;
156 guint32 *n_taps;
157 gdouble *taps;
158
159 /*< private >*/
160 gpointer _gst_reserved[GST_PADDING];
161};
162
163
164GST_VIDEO_API
165gboolean gst_video_resampler_init (GstVideoResampler *resampler,
166 GstVideoResamplerMethod method,
167 GstVideoResamplerFlags flags,
168 guint n_phases, guint n_taps,
169 gdouble shift,
170 guint in_size, guint out_size,
171 GstStructure *options);
172
173GST_VIDEO_API
174void gst_video_resampler_clear (GstVideoResampler *resampler);
175
176G_END_DECLS
177
178#endif /* __GST_VIDEO_RESAMPLER_H__ */
179

source code of include/gstreamer-1.0/gst/video/video-resampler.h