Commit f5eb3663 authored by Julien Isorce's avatar Julien Isorce Committed by Nicolas Dufresne
Browse files

allocators: define GST_CAPS_FEATURE_MEMORY_DMABUF

Adds "memory:DMABuf" caps feature. Since 1.11 tag.
Useful when the the dma-buf buffer cannot be mapped to CPU for r/w requests.
Example: protected content or platform constraints.

https://bugzilla.gnome.org/show_bug.cgi?id=759358
parent c37b1e8c
......@@ -4,6 +4,7 @@
<FILE>gstdmabuf</FILE>
<TITLE>dmabuf</TITLE>
<INCLUDE>gst/allocators/gstdmabuf.h</INCLUDE>
GST_CAPS_FEATURE_MEMORY_DMABUF
gst_dmabuf_allocator_new
gst_dmabuf_allocator_alloc
gst_dmabuf_memory_get_fd
......
......@@ -26,6 +26,38 @@
G_BEGIN_DECLS
/**
* GST_CAPS_FEATURE_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
*/
#define GST_CAPS_FEATURE_MEMORY_DMABUF "memory:DMABuf"
#define GST_ALLOCATOR_DMABUF "dmabuf"
#define GST_TYPE_DMABUF_ALLOCATOR (gst_dmabuf_allocator_get_type())
......
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