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bbca6b1ddf
Custom meta is backed by a GstStructure, and does not require that users of the API expose their GstMeta implementation as public API for other components to make use of it. In addition, it provides a simpler interface by ignoring the impl vs. api distinction that the regular API exposes. This new API is meant to be the meta counterpart to custom events and messages, and to be more convenient than the lower-level API when the absolute best performance isn't a requirement. Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/609>
302 lines
8.7 KiB
C
302 lines
8.7 KiB
C
/* GStreamer
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* Copyright (C) 2009 Wim Taymans <wim.taymans@gmail.be>
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*
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* gstmeta.h: Header for Metadata structures
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
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* Boston, MA 02110-1301, USA.
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*/
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#ifndef __GST_META_H__
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#define __GST_META_H__
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#include <glib.h>
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G_BEGIN_DECLS
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typedef struct _GstMeta GstMeta;
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typedef struct _GstMetaInfo GstMetaInfo;
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#define GST_META_CAST(meta) ((GstMeta *)(meta))
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/**
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* GstMetaFlags:
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* @GST_META_FLAG_NONE: no flags
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* @GST_META_FLAG_READONLY: metadata should not be modified
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* @GST_META_FLAG_POOLED: metadata is managed by a bufferpool
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* @GST_META_FLAG_LOCKED: metadata should not be removed
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* @GST_META_FLAG_LAST: additional flags can be added starting from this flag.
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*
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* Extra metadata flags.
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*/
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typedef enum {
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GST_META_FLAG_NONE = 0,
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GST_META_FLAG_READONLY = (1 << 0),
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GST_META_FLAG_POOLED = (1 << 1),
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GST_META_FLAG_LOCKED = (1 << 2),
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GST_META_FLAG_LAST = (1 << 16)
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} GstMetaFlags;
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/**
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* GST_META_FLAGS:
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* @meta: a #GstMeta.
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*
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* A flags word containing #GstMetaFlags flags set on @meta
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*/
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#define GST_META_FLAGS(meta) (GST_META_CAST (meta)->flags)
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/**
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* GST_META_FLAG_IS_SET:
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* @meta: a #GstMeta.
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* @flag: the #GstMetaFlags to check.
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*
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* Gives the status of a specific flag on a metadata.
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*/
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#define GST_META_FLAG_IS_SET(meta,flag) !!(GST_META_FLAGS (meta) & (flag))
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/**
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* GST_META_FLAG_SET:
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* @meta: a #GstMeta.
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* @flag: the #GstMetaFlags to set.
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*
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* Sets a metadata flag on a metadata.
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*/
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#define GST_META_FLAG_SET(meta,flag) (GST_META_FLAGS (meta) |= (flag))
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/**
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* GST_META_FLAG_UNSET:
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* @meta: a #GstMeta.
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* @flag: the #GstMetaFlags to clear.
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*
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* Clears a metadata flag.
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*/
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#define GST_META_FLAG_UNSET(meta,flag) (GST_META_FLAGS (meta) &= ~(flag))
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/**
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* GST_META_TAG_MEMORY_STR:
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*
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* This metadata stays relevant as long as memory layout is unchanged.
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*
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* Since: 1.2
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*/
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#define GST_META_TAG_MEMORY_STR "memory"
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/**
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* GstMeta:
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* @flags: extra flags for the metadata
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* @info: pointer to the #GstMetaInfo
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*
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* Base structure for metadata. Custom metadata will put this structure
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* as the first member of their structure.
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*/
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struct _GstMeta {
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GstMetaFlags flags;
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const GstMetaInfo *info;
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};
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/**
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* GstCustomMeta:
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*
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* Simple typing wrapper around #GstMeta
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*
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* Since: 1.20
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*/
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typedef struct {
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GstMeta meta;
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} GstCustomMeta;
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#include <gst/gstbuffer.h>
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/**
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* GstMetaInitFunction:
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* @meta: a #GstMeta
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* @params: parameters passed to the init function
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* @buffer: a #GstBuffer
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*
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* Function called when @meta is initialized in @buffer.
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*/
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typedef gboolean (*GstMetaInitFunction) (GstMeta *meta, gpointer params, GstBuffer *buffer);
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/**
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* GstMetaFreeFunction:
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* @meta: a #GstMeta
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* @buffer: a #GstBuffer
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*
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* Function called when @meta is freed in @buffer.
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*/
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typedef void (*GstMetaFreeFunction) (GstMeta *meta, GstBuffer *buffer);
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/**
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* gst_meta_transform_copy:
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*
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* GQuark for the "gst-copy" transform.
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*/
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GST_API GQuark _gst_meta_transform_copy;
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/**
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* GST_META_TRANSFORM_IS_COPY:
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* @type: a transform type
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*
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* Check if the transform type is a copy transform
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*/
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#define GST_META_TRANSFORM_IS_COPY(type) ((type) == _gst_meta_transform_copy)
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/**
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* GstMetaTransformCopy:
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* @region: %TRUE if only region is copied
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* @offset: the offset to copy, 0 if @region is %FALSE, otherwise > 0
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* @size: the size to copy, -1 or the buffer size when @region is %FALSE
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*
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* Extra data passed to a "gst-copy" transform #GstMetaTransformFunction.
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*/
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typedef struct {
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gboolean region;
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gsize offset;
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gsize size;
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} GstMetaTransformCopy;
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/**
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* GstMetaTransformFunction:
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* @transbuf: a #GstBuffer
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* @meta: a #GstMeta
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* @buffer: a #GstBuffer
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* @type: the transform type
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* @data: transform specific data.
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*
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* Function called for each @meta in @buffer as a result of performing a
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* transformation on @transbuf. Additional @type specific transform data
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* is passed to the function as @data.
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*
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* Implementations should check the @type of the transform and parse
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* additional type specific fields in @data that should be used to update
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* the metadata on @transbuf.
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*
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* Returns: %TRUE if the transform could be performed
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*/
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typedef gboolean (*GstMetaTransformFunction) (GstBuffer *transbuf,
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GstMeta *meta, GstBuffer *buffer,
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GQuark type, gpointer data);
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/**
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* GstCustomMetaTransformFunction:
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* @transbuf: a #GstBuffer
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* @meta: a #GstCustomMeta
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* @buffer: a #GstBuffer
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* @type: the transform type
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* @data: transform specific data.
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* @user_data: user data passed when registering the meta
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*
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* Function called for each @meta in @buffer as a result of performing a
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* transformation on @transbuf. Additional @type specific transform data
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* is passed to the function as @data.
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*
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* Implementations should check the @type of the transform and parse
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* additional type specific fields in @data that should be used to update
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* the metadata on @transbuf.
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*
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* Returns: %TRUE if the transform could be performed
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* Since: 1.20
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*/
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typedef gboolean (*GstCustomMetaTransformFunction) (GstBuffer *transbuf,
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GstCustomMeta *meta, GstBuffer *buffer,
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GQuark type, gpointer data, gpointer user_data);
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/**
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* GstMetaInfo:
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* @api: tag identifying the metadata structure and api
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* @type: type identifying the implementor of the api
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* @size: size of the metadata
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* @init_func: function for initializing the metadata
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* @free_func: function for freeing the metadata
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* @transform_func: function for transforming the metadata
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*
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* The #GstMetaInfo provides information about a specific metadata
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* structure.
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*/
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struct _GstMetaInfo {
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GType api;
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GType type;
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gsize size;
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GstMetaInitFunction init_func;
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GstMetaFreeFunction free_func;
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GstMetaTransformFunction transform_func;
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/* No padding needed, GstMetaInfo is always allocated by GStreamer and is
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* not subclassable or stack-allocatable, so we can extend it as we please
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* just like interfaces */
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};
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GST_API
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GType gst_meta_api_type_register (const gchar *api,
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const gchar **tags);
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GST_API
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gboolean gst_meta_api_type_has_tag (GType api, GQuark tag);
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GST_API
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const GstMetaInfo * gst_meta_register (GType api, const gchar *impl,
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gsize size,
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GstMetaInitFunction init_func,
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GstMetaFreeFunction free_func,
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GstMetaTransformFunction transform_func);
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GST_API
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const GstMetaInfo * gst_meta_register_custom (const gchar *name, const gchar **tags,
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GstCustomMetaTransformFunction transform_func,
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gpointer user_data, GDestroyNotify destroy_data);
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GST_API
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gboolean gst_meta_info_is_custom (const GstMetaInfo *info);
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GST_API
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GstStructure * gst_custom_meta_get_structure (GstCustomMeta *meta);
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GST_API
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gboolean gst_custom_meta_has_name (GstCustomMeta *meta, const gchar * name);
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GST_API
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const GstMetaInfo * gst_meta_get_info (const gchar * impl);
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GST_API
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const gchar* const* gst_meta_api_type_get_tags (GType api);
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GST_API
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guint64 gst_meta_get_seqnum (const GstMeta * meta);
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GST_API
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gint gst_meta_compare_seqnum (const GstMeta * meta1,
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const GstMeta * meta2);
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/* some default tags */
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GST_API GQuark _gst_meta_tag_memory;
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/**
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* GST_META_TAG_MEMORY:
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*
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* Metadata tagged with this tag depends on the particular memory
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* or buffer that it is on.
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*
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* Deprecated: The GQuarks are not exported by any public API, use
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* GST_META_TAG_MEMORY_STR instead.
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*/
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#ifndef GST_DISABLE_DEPRECATED
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#define GST_META_TAG_MEMORY (_gst_meta_tag_memory)
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#endif
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G_END_DECLS
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#endif /* __GST_META_H__ */
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