Constant that defines the caps feature name for DMA buffer sharing.
It has to be used for non-mappable dma-buf only, i.e. when the underlying
memory is not mappable to user space. Or when the mapped memory contains
non meaningful data. It can be the case for protected content or when the
user wants explicitly avoid any software post processing.
In these cases all elements between the exported and the importer has to work
in passthrough mode. This is done by adding this caps feature.
When the memory is mappable for read and write requests then it is assumes
to be a fast path and so this caps feature should not be used. Though
according to the dma-buf protocol, while it is mapped it prevents the
exporter to migrate the buffer.
This caps feature should not serve at all the purpose of selecting the
@GST_ALLOCATOR_DMABUF allocator during caps negotiation.
When the exporter is the upstream element from the importer point of view,
the exporter should try to map the dma buffer at runtime (preferably during
decide_allocation phase). When it succeeds for #GST_MAP_READWRITE this caps
feature should not be used. This allows scalers, color converts and any image
processing filters to work directly on the dma buffer.
In this case the importer element should check all incoming memory using
gst_is_dmabuf_memory().
Base class for allocators with dmabuf-backed memory
Return a new dmabuf allocator.
a new dmabuf allocator, or NULL if the allocator
isn't available. Use gst_object_unref() to release the allocator after
usage
Return a %GstMemory that wraps a dmabuf file descriptor.
a GstMemory based on @allocator.
When the buffer will be released dmabuf allocator will close the @fd.
The memory is only mmapped on gst_buffer_map() request.
allocator to be used for this memory
dmabuf file descriptor
memory size
Return a %GstMemory that wraps a dmabuf file descriptor.
a GstMemory based on @allocator.
When the buffer will be released the allocator will close the @fd unless
the %GST_FD_MEMORY_FLAG_DONT_CLOSE flag is specified.
The memory is only mmapped on gst_buffer_mmap() request.
allocator to be used for this memory
dmabuf file descriptor
memory size
extra #GstFdMemoryFlags
Base class for allocators with fd-backed memory
Return a new fd allocator.
a new fd allocator, or NULL if the allocator
isn't available. Use gst_object_unref() to release the allocator after
usage
Return a %GstMemory that wraps a generic file descriptor.
a GstMemory based on @allocator.
When the buffer will be released the allocator will close the @fd unless
the %GST_FD_MEMORY_FLAG_DONT_CLOSE flag is specified.
The memory is only mmapped on gst_buffer_map() request.
allocator to be used for this memory
file descriptor
memory size
extra #GstFdMemoryFlags
Various flags to control the operation of the fd backed memory.
no flag
once the memory is mapped,
keep it mapped until the memory is destroyed.
do a private mapping instead of
the default shared mapping.
don't close the file descriptor when
the memory is freed. Since: 1.10
Marker interface for allocators with physical address backed memory
Return the file descriptor associated with @mem.
the file descriptor associated with the memory, or -1. The file
descriptor is still owned by the GstMemory. Use dup to take a copy
if you intend to use it beyond the lifetime of this GstMemory.
the memory to get the file descriptor
Get the fd from @mem. Call gst_is_fd_memory() to check if @mem has
an fd.
the fd of @mem or -1 when there is no fd on @mem
#GstMemory
Check if @mem is dmabuf memory.
%TRUE if @mem is dmabuf memory, otherwise %FALSE
the memory to be check
Check if @mem is memory backed by an fd
%TRUE when @mem has an fd that can be retrieved with
gst_fd_memory_get_fd().
#GstMemory
whether the memory at @mem is backed by physical memory
a #GstMemory
Physical memory address that is backing @mem, or 0 if none
a #GstMemory