/* GStreamer * Copyright (C) 2009 Wim Taymans * * gstmeta.h: Header for Metadata structures * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Library General Public * License as published by the Free Software Foundation; either * version 2 of the License, or (at your option) any later version. * * This library 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 * Library General Public License for more details. * * You should have received a copy of the GNU Library General Public * License along with this library; if not, write to the * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, * Boston, MA 02110-1301, USA. */ #ifndef __GST_META_H__ #define __GST_META_H__ #include G_BEGIN_DECLS typedef struct _GstMeta GstMeta; typedef struct _GstMetaInfo GstMetaInfo; #define GST_META_CAST(meta) ((GstMeta *)(meta)) /** * GstMetaFlags: * @GST_META_FLAG_NONE: no flags * @GST_META_FLAG_READONLY: metadata should not be modified * @GST_META_FLAG_POOLED: metadata is managed by a bufferpool * @GST_META_FLAG_LOCKED: metadata should not be removed * @GST_META_FLAG_LAST: additional flags can be added starting from this flag. * * Extra metadata flags. */ typedef enum { GST_META_FLAG_NONE = 0, GST_META_FLAG_READONLY = (1 << 0), GST_META_FLAG_POOLED = (1 << 1), GST_META_FLAG_LOCKED = (1 << 2), GST_META_FLAG_LAST = (1 << 16) } GstMetaFlags; /** * GST_META_FLAGS: * @meta: a #GstMeta. * * A flags word containing #GstMetaFlags flags set on @meta */ #define GST_META_FLAGS(meta) (GST_META_CAST (meta)->flags) /** * GST_META_FLAG_IS_SET: * @meta: a #GstMeta. * @flag: the #GstMetaFlags to check. * * Gives the status of a specific flag on a metadata. */ #define GST_META_FLAG_IS_SET(meta,flag) !!(GST_META_FLAGS (meta) & (flag)) /** * GST_META_FLAG_SET: * @meta: a #GstMeta. * @flag: the #GstMetaFlags to set. * * Sets a metadata flag on a metadata. */ #define GST_META_FLAG_SET(meta,flag) (GST_META_FLAGS (meta) |= (flag)) /** * GST_META_FLAG_UNSET: * @meta: a #GstMeta. * @flag: the #GstMetaFlags to clear. * * Clears a metadata flag. */ #define GST_META_FLAG_UNSET(meta,flag) (GST_META_FLAGS (meta) &= ~(flag)) /** * GST_META_TAG_MEMORY_STR: * * This metadata stays relevant as long as memory layout is unchanged. * * Since: 1.2 */ #define GST_META_TAG_MEMORY_STR "memory" /** * GstMeta: * @flags: extra flags for the metadata * @info: pointer to the #GstMetaInfo * * Base structure for metadata. Custom metadata will put this structure * as the first member of their structure. */ struct _GstMeta { GstMetaFlags flags; const GstMetaInfo *info; }; #include /** * GstMetaInitFunction: * @meta: a #GstMeta * @params: parameters passed to the init function * @buffer: a #GstBuffer * * Function called when @meta is initialized in @buffer. */ typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuffer *buffer); /** * GstMetaFreeFunction: * @meta: a #GstMeta * @buffer: a #GstBuffer * * Function called when @meta is freed in @buffer. */ typedef void (*GstMetaFreeFunction) (GstMeta *meta, GstBuffer *buffer); /** * gst_meta_transform_copy: * * GQuark for the "gst-copy" transform. */ GST_API GQuark _gst_meta_transform_copy; /** * GST_META_TRANSFORM_IS_COPY: * @type: a transform type * * Check if the transform type is a copy transform */ #define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy) /** * GstMetaTransformCopy: * @region: %TRUE if only region is copied * @offset: the offset to copy, 0 if @region is %FALSE, otherwise > 0 * @size: the size to copy, -1 or the buffer size when @region is %FALSE * * Extra data passed to a "gst-copy" transform #GstMetaTransformFunction. */ typedef struct { gboolean region; gsize offset; gsize size; } GstMetaTransformCopy; /** * GstMetaTransformFunction: * @transbuf: a #GstBuffer * @meta: a #GstMeta * @buffer: a #GstBuffer * @type: the transform type * @data: transform specific data. * * Function called for each @meta in @buffer as a result of performing a * transformation on @transbuf. Additional @type specific transform data * is passed to the function as @data. * * Implementations should check the @type of the transform and parse * additional type specific fields in @data that should be used to update * the metadata on @transbuf. * * Returns: %TRUE if the transform could be performed */ typedef gboolean (*GstMetaTransformFunction) (GstBuffer *transbuf, GstMeta *meta, GstBuffer *buffer, GQuark type, gpointer data); /** * GstMetaInfo: * @api: tag identifying the metadata structure and api * @type: type identifying the implementor of the api * @size: size of the metadata * @init_func: function for initializing the metadata * @free_func: function for freeing the metadata * @transform_func: function for transforming the metadata * * The #GstMetaInfo provides information about a specific metadata * structure. */ struct _GstMetaInfo { GType api; GType type; gsize size; GstMetaInitFunction init_func; GstMetaFreeFunction free_func; GstMetaTransformFunction transform_func; /* No padding needed, GstMetaInfo is always allocated by GStreamer and is * not subclassable or stack-allocatable, so we can extend it as we please * just like interfaces */ }; GST_API GType gst_meta_api_type_register (const gchar *api, const gchar **tags); GST_API gboolean gst_meta_api_type_has_tag (GType api, GQuark tag); GST_API const GstMetaInfo * gst_meta_register (GType api, const gchar *impl, gsize size, GstMetaInitFunction init_func, GstMetaFreeFunction free_func, GstMetaTransformFunction transform_func); GST_API const GstMetaInfo * gst_meta_get_info (const gchar * impl); GST_API const gchar* const* gst_meta_api_type_get_tags (GType api); /* some default tags */ GST_API GQuark _gst_meta_tag_memory; /** * GST_META_TAG_MEMORY: * * Metadata tagged with this tag depends on the particular memory * or buffer that it is on. * * Deprecated: The GQuarks are not exported by any public API, use * GST_META_TAG_MEMORY_STR instead. */ #ifndef GST_DISABLE_DEPRECATED #define GST_META_TAG_MEMORY (_gst_meta_tag_memory) #endif G_END_DECLS #endif /* __GST_META_H__ */