GstBufferList

GstBufferList — Lists of buffers for data-passing

Functions

Types and Values

Object Hierarchy

    GBoxed
    ╰── GstBufferList

Includes

#include <gst/gst.h>

Description

Buffer lists are an object containing a list of buffers.

Buffer lists are created with gst_buffer_list_new() and filled with data using a gst_buffer_list_insert().

Buffer lists can be pushed on a srcpad with gst_pad_push_list(). This is interesting when multiple buffers need to be pushed in one go because it can reduce the amount of overhead for pushing each buffer individually.

Functions

gst_buffer_list_new ()

GstBufferList *
gst_buffer_list_new (void);

Creates a new, empty GstBufferList. The caller is responsible for unreffing the returned GstBufferList.

Free-function: gst_buffer_list_unref

Returns

the new GstBufferList. gst_buffer_list_unref() after usage.

[transfer full]


gst_buffer_list_new_sized ()

GstBufferList *
gst_buffer_list_new_sized (guint size);

Creates a new, empty GstBufferList. The caller is responsible for unreffing the returned GstBufferList. The list will have size space preallocated so that memory reallocations can be avoided.

Free-function: gst_buffer_list_unref

Parameters

size

an initial reserved size

 

Returns

the new GstBufferList. gst_buffer_list_unref() after usage.

[transfer full]


gst_buffer_list_length ()

guint
gst_buffer_list_length (GstBufferList *list);

Returns the number of buffers in list .

Parameters

list

a GstBufferList

 

Returns

the number of buffers in the buffer list


gst_buffer_list_add()

#define gst_buffer_list_add(l,b) gst_buffer_list_insert((l),-1,(b));

Append b at the end of l .

Parameters

l

a GstBufferList

 

b

a GstBuffer

 

gst_buffer_list_insert ()

void
gst_buffer_list_insert (GstBufferList *list,
                        gint idx,
                        GstBuffer *buffer);

Insert buffer at idx in list . Other buffers are moved to make room for this new buffer.

A -1 value for idx will append the buffer at the end.

Parameters

list

a GstBufferList

 

idx

the index

 

buffer

a GstBuffer.

[transfer full]

gst_buffer_list_remove ()

void
gst_buffer_list_remove (GstBufferList *list,
                        guint idx,
                        guint length);

Remove length buffers starting from idx in list . The following buffers are moved to close the gap.

Parameters

list

a GstBufferList

 

idx

the index

 

length

the amount to remove

 

gst_buffer_list_ref ()

GstBufferList *
gst_buffer_list_ref (GstBufferList *list);

Increases the refcount of the given buffer list by one.

Note that the refcount affects the writability of list and its data, see gst_buffer_list_make_writable(). It is important to note that keeping additional references to GstBufferList instances can potentially increase the number of memcpy operations in a pipeline.

Parameters

list

a GstBufferList

 

Returns

list .

[transfer full]


gst_buffer_list_unref ()

void
gst_buffer_list_unref (GstBufferList *list);

Decreases the refcount of the buffer list. If the refcount reaches 0, the buffer list will be freed.

Parameters

list

a GstBufferList.

[transfer full]

gst_buffer_list_copy ()

GstBufferList *
gst_buffer_list_copy (const GstBufferList *list);

Create a shallow copy of the given buffer list. This will make a newly allocated copy of the source list with copies of buffer pointers. The refcount of buffers pointed to will be increased by one.

Parameters

list

a GstBufferList

 

Returns

a new copy of list .

[transfer full]


gst_buffer_list_is_writable()

#define gst_buffer_list_is_writable(list) gst_mini_object_is_writable (GST_MINI_OBJECT_CAST (list))

Tests if you can safely add buffers and groups into a buffer list.

Parameters

list

a GstBufferList

 

gst_buffer_list_make_writable()

#define gst_buffer_list_make_writable(list) GST_BUFFER_LIST_CAST (gst_mini_object_make_writable (GST_MINI_OBJECT_CAST (list)))

Makes a writable buffer list from the given buffer list. If the source buffer list is already writable, this will simply return the same buffer list. A copy will otherwise be made using gst_buffer_list_copy().

Parameters

list

a GstBufferList.

[transfer full]

Returns

a writable list, which may or may not be the same as list .

[transfer full]


GstBufferListFunc ()

gboolean
(*GstBufferListFunc) (GstBuffer **buffer,
                      guint idx,
                      gpointer user_data);

A function that will be called from gst_buffer_list_foreach(). The buffer field will point to a the reference of the buffer at idx .

When this function returns TRUE, the next buffer will be returned. When FALSE is returned, gst_buffer_list_foreach() will return.

When buffer is set to NULL, the item will be removed from the bufferlist. When buffer has been made writable, the new buffer reference can be assigned to buffer . This function is responsible for unreffing the old buffer when removing or modifying.

Parameters

buffer

pointer the buffer.

[out][nullable]

idx

the index of buffer

 

user_data

user data passed to gst_buffer_list_foreach()

 

Returns

FALSE when gst_buffer_list_foreach() should stop


gst_buffer_list_foreach ()

gboolean
gst_buffer_list_foreach (GstBufferList *list,
                         GstBufferListFunc func,
                         gpointer user_data);

Call func with data for each buffer in list .

func can modify the passed buffer pointer or its contents. The return value of func define if this function returns or if the remaining buffers in the list should be skipped.

Parameters

list

a GstBufferList

 

func

a GstBufferListFunc to call.

[scope call]

user_data

user data passed to func .

[closure]

Returns

TRUE when func returned TRUE for each buffer in list or when list is empty.


gst_buffer_list_get ()

GstBuffer *
gst_buffer_list_get (GstBufferList *list,
                     guint idx);

Get the buffer at idx .

Parameters

list

a GstBufferList

 

idx

the index

 

Returns

the buffer at idx in group or NULL when there is no buffer. The buffer remains valid as long as list is valid.

[transfer none][nullable]

Types and Values

GstBufferList

typedef struct _GstBufferList GstBufferList;

Opaque list of grouped buffers.

See Also

GstPad, GstMiniObject