1/* GStreamer
2 * Copyright (C) 2009 Wim Taymans <[email protected]>
3 *
4 * gstmeta.h: Header for Metadata structures
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22
23#ifndef __GST_META_H__
24#define __GST_META_H__
25
26#include <glib.h>
27
28G_BEGIN_DECLS
29
30typedef struct _GstMeta GstMeta;
31typedef struct _GstMetaInfo GstMetaInfo;
32
33#define GST_META_CAST(meta) ((GstMeta *)(meta))
34
35/**
36 * GstMetaFlags:
37 * @GST_META_FLAG_NONE: no flags
38 * @GST_META_FLAG_READONLY: metadata should not be modified
39 * @GST_META_FLAG_POOLED: metadata is managed by a bufferpool
40 * @GST_META_FLAG_LOCKED: metadata should not be removed
41 * @GST_META_FLAG_LAST: additional flags can be added starting from this flag.
42 *
43 * Extra metadata flags.
44 */
45typedef enum {
46 GST_META_FLAG_NONE = 0,
47 GST_META_FLAG_READONLY = (1 << 0),
48 GST_META_FLAG_POOLED = (1 << 1),
49 GST_META_FLAG_LOCKED = (1 << 2),
50
51 GST_META_FLAG_LAST = (1 << 16)
52} GstMetaFlags;
53
54/**
55 * GST_META_FLAGS:
56 * @meta: a #GstMeta.
57 *
58 * A flags word containing #GstMetaFlags flags set on @meta
59 */
60#define GST_META_FLAGS(meta) (GST_META_CAST (meta)->flags)
61/**
62 * GST_META_FLAG_IS_SET:
63 * @meta: a #GstMeta.
64 * @flag: the #GstMetaFlags to check.
65 *
66 * Gives the status of a specific flag on a metadata.
67 */
68#define GST_META_FLAG_IS_SET(meta,flag) !!(GST_META_FLAGS (meta) & (flag))
69/**
70 * GST_META_FLAG_SET:
71 * @meta: a #GstMeta.
72 * @flag: the #GstMetaFlags to set.
73 *
74 * Sets a metadata flag on a metadata.
75 */
76#define GST_META_FLAG_SET(meta,flag) (GST_META_FLAGS (meta) |= (flag))
77/**
78 * GST_META_FLAG_UNSET:
79 * @meta: a #GstMeta.
80 * @flag: the #GstMetaFlags to clear.
81 *
82 * Clears a metadata flag.
83 */
84#define GST_META_FLAG_UNSET(meta,flag) (GST_META_FLAGS (meta) &= ~(flag))
85
86/**
87 * GST_META_TAG_MEMORY_STR:
88 *
89 * This metadata stays relevant as long as memory layout is unchanged.
90 *
91 * Since: 1.2
92 */
93#define GST_META_TAG_MEMORY_STR "memory"
94
95/**
96 * GstMeta:
97 * @flags: extra flags for the metadata
98 * @info: pointer to the #GstMetaInfo
99 *
100 * Base structure for metadata. Custom metadata will put this structure
101 * as the first member of their structure.
102 */
103struct _GstMeta {
104 GstMetaFlags flags;
105 const GstMetaInfo *info;
106};
107
108#include <gst/gstbuffer.h>
109
110/**
111 * GstMetaInitFunction:
112 * @meta: a #GstMeta
113 * @params: parameters passed to the init function
114 * @buffer: a #GstBuffer
115 *
116 * Function called when @meta is initialized in @buffer.
117 */
118typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuffer *buffer);
119
120/**
121 * GstMetaFreeFunction:
122 * @meta: a #GstMeta
123 * @buffer: a #GstBuffer
124 *
125 * Function called when @meta is freed in @buffer.
126 */
127typedef void (*GstMetaFreeFunction) (GstMeta *meta, GstBuffer *buffer);
128
129/**
130 * gst_meta_transform_copy:
131 *
132 * GQuark for the "gst-copy" transform.
133 */
134
135GST_API GQuark _gst_meta_transform_copy;
136
137/**
138 * GST_META_TRANSFORM_IS_COPY:
139 * @type: a transform type
140 *
141 * Check if the transform type is a copy transform
142 */
143#define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy)
144
145/**
146 * GstMetaTransformCopy:
147 * @region: %TRUE if only region is copied
148 * @offset: the offset to copy, 0 if @region is %FALSE, otherwise > 0
149 * @size: the size to copy, -1 or the buffer size when @region is %FALSE
150 *
151 * Extra data passed to a "gst-copy" transform #GstMetaTransformFunction.
152 */
153typedef struct {
154 gboolean region;
155 gsize offset;
156 gsize size;
157} GstMetaTransformCopy;
158
159/**
160 * GstMetaTransformFunction:
161 * @transbuf: a #GstBuffer
162 * @meta: a #GstMeta
163 * @buffer: a #GstBuffer
164 * @type: the transform type
165 * @data: transform specific data.
166 *
167 * Function called for each @meta in @buffer as a result of performing a
168 * transformation on @transbuf. Additional @type specific transform data
169 * is passed to the function as @data.
170 *
171 * Implementations should check the @type of the transform and parse
172 * additional type specific fields in @data that should be used to update
173 * the metadata on @transbuf.
174 *
175 * Returns: %TRUE if the transform could be performed
176 */
177typedef gboolean (*GstMetaTransformFunction) (GstBuffer *transbuf,
178 GstMeta *meta, GstBuffer *buffer,
179 GQuark type, gpointer data);
180
181/**
182 * GstMetaInfo:
183 * @api: tag identifying the metadata structure and api
184 * @type: type identifying the implementor of the api
185 * @size: size of the metadata
186 * @init_func: function for initializing the metadata
187 * @free_func: function for freeing the metadata
188 * @transform_func: function for transforming the metadata
189 *
190 * The #GstMetaInfo provides information about a specific metadata
191 * structure.
192 */
193struct _GstMetaInfo {
194 GType api;
195 GType type;
196 gsize size;
197
198 GstMetaInitFunction init_func;
199 GstMetaFreeFunction free_func;
200 GstMetaTransformFunction transform_func;
201
202 /* No padding needed, GstMetaInfo is always allocated by GStreamer and is
203 * not subclassable or stack-allocatable, so we can extend it as we please
204 * just like interfaces */
205};
206
207GST_API
208GType gst_meta_api_type_register (const gchar *api,
209 const gchar **tags);
210GST_API
211gboolean gst_meta_api_type_has_tag (GType api, GQuark tag);
212
213GST_API
214const GstMetaInfo * gst_meta_register (GType api, const gchar *impl,
215 gsize size,
216 GstMetaInitFunction init_func,
217 GstMetaFreeFunction free_func,
218 GstMetaTransformFunction transform_func);
219GST_API
220const GstMetaInfo * gst_meta_get_info (const gchar * impl);
221
222GST_API
223const gchar* const* gst_meta_api_type_get_tags (GType api);
224
225GST_API
226guint64 gst_meta_get_seqnum (const GstMeta * meta);
227
228GST_API
229gint gst_meta_compare_seqnum (const GstMeta * meta1,
230 const GstMeta * meta2);
231
232/* some default tags */
233
234GST_API GQuark _gst_meta_tag_memory;
235
236/**
237 * GST_META_TAG_MEMORY:
238 *
239 * Metadata tagged with this tag depends on the particular memory
240 * or buffer that it is on.
241 *
242 * Deprecated: The GQuarks are not exported by any public API, use
243 * GST_META_TAG_MEMORY_STR instead.
244 */
245#ifndef GST_DISABLE_DEPRECATED
246#define GST_META_TAG_MEMORY (_gst_meta_tag_memory)
247#endif
248
249G_END_DECLS
250
251#endif /* __GST_META_H__ */
252