It is incorrect to modify the frame properties after passing them, since
VTCompressionSessionEncodeFrame takes reference and we have no control
over when it's being used.
In fact, the code can be simplified. We just preallocate the frame
properties for keyframe requests, and pass NULL otherwise.
https://bugzilla.gnome.org/show_bug.cgi?id=748467
The codec that called us might be holding locks to shared resources, so
we should never push downstream from within its buffer callback.
Note that a GstBufferList is not used here because we need to preserve
the buffer metadata held by our GstBuffer subclasses.
Provides the following elements:
qtkitvideosrc: OS X video source relying on the QTKit API. Comes with
hard-coded caps as the API does not provide any way of querying for
formats supported by the hardware. Hasn't been tested a lot, but seems
to work.
miovideosrc: OS X video source which uses the undocumented/private
CoreMediaIOServices API, which is also the one used by iChat.
Present on latest version of Leopard and all versions of Snow Leopard.
Has been tested extensively with built-in cameras and TANDBERG's
PrecisionHD USB camera.
vtenc, vtdec: Generic codec wrappers which make use of the undocumented/
private VideoToolbox API on OS X and iOS. List of codecs are currently
hard-coded to H.264 for vtenc, and H.264 + JPEG for vtdec. Can easily be
expanded by adding new entries to the lists, but haven't yet had time to
do that. Should probably also implement probing as available codecs depend
on the OS and its version, and there doesn't seem to be any way to
enumerate the available codecs.
vth264decbin, vth264encbin: Wrapper bins to make it easier to use
vtdec_h264/vtenc_h264 in live scenarios.
iphonecamerasrc: iPhone camera source relying on the undocumented/private
Celestial API. Tested on iOS 3.1 running on an iPhone 3GS. Stops working
after a few minutes, presumably because of a resource leak. Needs some
love.
Note that the iOS parts haven't yet been ported to iOS 4.x.
