anx_import.h File Reference

Specification of AnxImporter. More...

#include <annodex/anx_types.h>
#include <annodex/anx_core.h>

Go to the source code of this file.

Data Structures
struct	_AnxImporter
struct	_AnxSourceTrack
struct	_AnxSource

Typedefs
typedef struct _AnxImporter	AnxImporter
	An AnxImporter implements generic functions for retrieving data from sources of a particular content type.
typedef struct _AnxSourceTrack	AnxSourceTrack
	An AnxSourceTrack contains one track of data.
typedef struct _AnxSource	AnxSource
	An AnxSource contains an instance of an active source object, which may in turn contain several tracks.
typedef AnxSource *(*	AnxImporterOpenFunc) (const char *path, const char *id, int ignore_raw, double start_time, double end_time, AnxImportCallbacks *import_callbacks)
	Signature of a function for opening a source object by filename.
typedef AnxSource *(*	AnxImporterOpenFDFunc) (int fd, const char *id, int ignore_raw, double start_time, double end_time, AnxImportCallbacks *import_callbacks)
	Signature of a function for opening a source object attached to an open file descriptor.
typedef long(*	AnxImporterReadFunc) (AnxSource *source, unsigned char *buf, long n, long bound)
	Signature of a function for reading bytes from a source object.
typedef long(*	AnxImporterSizeofNextReadFunc) (AnxSource *source, long bound)
	Signature of a function to return the preferred next read size.
typedef int(*	AnxImporterCloseFunc) (AnxSource *source)
	Signature of a function to close a source object.

Functions
int	anx_importer_register (AnxImporter *importer)
	Register an AnxImporter object with libannodex.
int	anx_importer_unregister (AnxImporter *importer)
	Unregister an AnxImporter previously registered with libannodex.
AnxImporter *	anx_importer_find (char *content_type)
	Find the AnxImporter registered with the given content type.

Detailed Description

Specification of AnxImporter.

• When read requires starting a new frame or GOP, check the need_sync flag. If this is set, output a sync frame.

Note

Always check not to seek before start_packet and not to seek or read past end_packet.

• seek should return the actual position after seeking (as the backend may not be able to seek exactly to the requested position).

Backends must implement the following function:

• AnxImporter * anx_importer_init (int i);

Importers are accessed by index i using values from 0 upwards. For out of range indexes, this function must return NULL.

No other symbols in a backend should be visible (ie. declare all other globals and functions as static).

Typedef Documentation

AnxImporterCloseFunc

typedef int(* AnxImporterCloseFunc) (AnxSource *source)

Signature of a function to close a source object.

Parameters

source

an AnxSource* handle

AnxImporterOpenFDFunc

typedef AnxSource *(* AnxImporterOpenFDFunc) (int fd, const char *id, int ignore_raw, double start_time, double end_time, AnxImportCallbacks *import_callbacks)

Signature of a function for opening a source object attached to an open file descriptor.

Parameters

fd	an open file descriptor
id	the id of this
ignore_raw	a flag to indicate that the importer should ignore any raw source read requests, ie. just deliver clips
start_time	the start time to initially seek to
end_time	a time bound to end on
import_callbacks	callbacks to call when further importing or anchor inserting is required.

Returns

a new AnxSource * handle

AnxImporterOpenFunc

typedef AnxSource *(* AnxImporterOpenFunc) (const char *path, const char *id, int ignore_raw, double start_time, double end_time, AnxImportCallbacks *import_callbacks)

Signature of a function for opening a source object by filename.

Parameters

path	the path to the source file
id	the id of this
ignore_raw	a flag to indicate that the importer should ignore any raw source read requests, ie. just deliver clips
start_time	the start time to initially seek to
end_time	a time bound to end on
import_callbacks	callbacks to call when further importing or anchor inserting is required.

Returns

a new AnxSource * handle

AnxImporterReadFunc

typedef long(* AnxImporterReadFunc) (AnxSource *source, unsigned char *buf, long n, long bound)

Signature of a function for reading bytes from a source object.

Parameters

source	an AnxSource * handle
buf	a buffer to read data into
n	a maximum number of bytes to read
bound	a maximum granulecount to read

AnxImporterSizeofNextReadFunc

typedef long(* AnxImporterSizeofNextReadFunc) (AnxSource *source, long bound)

Signature of a function to return the preferred next read size.

Parameters

source	an AnxSource * handle
bound	a maximum granulecount to read

Function Documentation

anx_importer_find()

AnxImporter * anx_importer_find

(

char *

content_type

)

Find the AnxImporter registered with the given content type.

Parameters

content_type

the content type

Returns

the AnxImporter * on success, NULL on failure

anx_importer_register()

int anx_importer_register

(

AnxImporter *

importer

)

Register an AnxImporter object with libannodex.

Parameters

importer

the importer

Returns

0 on success, -1 on failure

anx_importer_unregister()

int anx_importer_unregister

(

AnxImporter *

importer

)

Unregister an AnxImporter previously registered with libannodex.

Parameters

importer

the importer

Returns

0 on success, -1 on failure