the alignment of the memory
pointer to the #GstAllocator
the maximum size allocated
parent structure
the offset where valid data starts
parent memory block
the size of valid data
Return a copy of size bytes from mem starting from offset. This copy is
guaranteed to be writable. size can be set to -1 to return a copy
from offset to the end of the memory region.
offset to copy from
size to copy, or -1 to copy to the end of the memory region
Get the current size, offset and maxsize of mem.
Check if mem1 and mem2 share the memory with a common parent memory object
and that the memory is contiguous.
If this is the case, the memory of mem1 and mem2 can be merged
efficiently by performing gst_memory_share() on the parent object from
the returned offset.
a #GstMemory
Check if mem if allocated with an allocator for mem_type.
a memory type
Fill info with the pointer and sizes of the memory in mem that can be
accessed according to flags.
This function can return %FALSE for various reasons:
mem is not accessible with the given flags.info and its contents remain valid for as long as mem is valid and
until gst_memory_unmap() is called.
For each gst_memory_map() call, a corresponding gst_memory_unmap() call should be done.
Resize the memory region. mem should be writable and offset + size should be
less than the maxsize of mem.
#GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED will be cleared when offset or padding is increased respectively.
a new offset
a new size
Return a shared copy of size bytes from mem starting from offset. No
memory copy is performed and the memory region is simply shared. The result
is guaranteed to be non-writable. size can be set to -1 to return a shared
copy from offset to the end of the memory region.
offset to share from
size to share, or -1 to share to the end of the memory region
Release the memory obtained with gst_memory_map()
a #GstMapInfo
Allocate a new memory block that wraps the given data.
The prefix/padding must be filled with 0 if flags contains
#GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
#GstMemoryFlags
data to wrap
allocated size of data
offset in data
called with user_data when the memory is freed
GstMemory is a lightweight refcounted object that wraps a region of memory. They are typically used to manage the data of a #GstBuffer.
A GstMemory object has an allocated region of memory of maxsize. The maximum size does not change during the lifetime of the memory object. The memory also has an offset and size property that specifies the valid range of memory in the allocated region.
Memory is usually created by allocators with a gst_allocator_alloc() method call. When %NULL is used as the allocator, the default allocator will be used.
New allocators can be registered with gst_allocator_register(). Allocators are identified by name and can be retrieved with gst_allocator_find(). gst_allocator_set_default() can be used to change the default allocator.
New memory can be created with gst_memory_new_wrapped() that wraps the memory allocated elsewhere.
Refcounting of the memory block is performed with gst_memory_ref() and gst_memory_unref().
The size of the memory can be retrieved and changed with gst_memory_get_sizes() and gst_memory_resize() respectively.
Getting access to the data of the memory is performed with gst_memory_map(). The call will return a pointer to offset bytes into the region of memory. After the memory access is completed, gst_memory_unmap() should be called.
Memory can be copied with gst_memory_copy(), which will return a writable copy. gst_memory_share() will create a new memory block that shares the memory with an existing memory block at a custom offset and with a custom size.
Memory can be efficiently merged when gst_memory_is_span() returns %TRUE.