The difference between mmap and mmap64 is the type of 'offset' argument.
mmap64 always uses a 64-bit interger as offset, while mmap uses off_t,
whose size can vary on different operating systems or architectures.
However, not all operating systems support mmap64. Fortunately, although
FreeBSD only has mmap, its off_t is always 64-bit regardless of
architectures, so we can simply use mmap when sizeof(off_t) == 8.
https://bugzilla.gnome.org/show_bug.cgi?id=791779
Even though hooked up to the build system, it's clear that no one
has ever built or used this with GStreamer 1.x. It wants to link
against libgstinterfaces, which no longer exists. And uses 0.10-style
raw audio caps. And the last meaningful change was done in 2009.
Let's just remove it.
That example only tested the property probe interface, which has been removed.
The same kind of thing can now be done with the generic gst-device-monitor tool.
Most of those have V4L2 drivers these days enabling it make sure that it
this code is enabled in major distribution, hence that HW accelerated
decoder/encoder can be used on platforms that support it. The probes are
slightly increasing the first init of gstreamer library, though the
result is cached in the registry for later use.
With the VPX decoders it's not simple to use downstream buffer pool,
because we don't know the image size and alignment when buffers get
allocated. We can though use GstAllocator (for downstream, or the system
allocator) to avoid a copy before pushing if downstream supports
GstVideoMeta. This would still cause a copy for sink that requires
specialized memory and does not have a GstAllocator for that, though
it will greatly improve performance for sink like glimagesink and
cluttersink. To avoid allocating for every buffer, we also use a
internal buffer pool.
https://bugzilla.gnome.org/show_bug.cgi?id=745372
If something in /dev/video* get added, removed or replaced, we need to
probe the devices again in order to ensure the dynamic devices are up to
date.
https://bugzilla.gnome.org/show_bug.cgi?id=758085
