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GstAllocator *
gst_dmabuf_allocator_new (void);
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.
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Since: 1.2
GstMemory * gst_dmabuf_allocator_alloc (GstAllocator *allocator,gint fd,gsize size);
Return a GstMemory that wraps a dmabuf file descriptor.
allocator |
allocator to be used for this memory |
|
fd |
dmabuf file descriptor |
|
size |
memory size |
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_mmap() request.
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Since: 1.2
gint
gst_dmabuf_memory_get_fd (GstMemory *mem);
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.
Since: 1.2
#define GST_CAPS_FEATURE_MEMORY_DMABUF "memory:DMABuf"
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 protocal, 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 (preferrably 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 incomming memory using
gst_is_dmabuf_memory().
Since: 1.11