![]() |
![]() |
![]() |
GStreamer Good Plugins 0.10 Plugins Reference Manual | ![]() |
---|---|---|---|---|
GObject +----GstObject +----GstElement +----GstBaseSink +----GstVideoSink +----GstGdkPixbufSink
This sink element takes RGB or RGBA images as input and wraps them into GdkPixbuf objects, for easy saving to file via the GdkPixbuf library API or displaying in Gtk+ applications (e.g. using the GtkImage widget).
There are two ways to use this element and obtain the GdkPixbuf objects created:
"preroll-pixbuf"
or "pixbuf"
on the bus, which
will be posted whenever an image would usually be rendered. See below for
more details on these messages and how to extract the pixbuf object
contained in them.
"last-pixbuf"
property when needed.
The primary purpose of this element is to abstract away the GstBuffer to GdkPixbuf conversion. Other than that it's very similar to the fakesink element.
This element is meant for easy no-hassle video snapshotting. It is not suitable for video playback or video display at high framerates. Use ximagesink, xvimagesink or some other suitable video sink in connection with the GstXOverlay interface instead if you want to do video playback.
As mentioned above, this element will by default post element messages
containing structures named "preroll-pixbuf"
or "pixbuf"
on the bus (this
can be disabled by setting the
"send-messages"
property to FALSE though). The element message's structure
will have the following fields:
"pixbuf"
: the GdkPixbuf object
"pixel-aspect-ratio"
: the pixel aspect
ratio (PAR) of the input image (this field contains a GstFraction); the
PAR is usually 1:1 for images, but is often something non-1:1 in the case
of video input. In this case the image may be distorted and you may need
to rescale it accordingly before saving it to file or displaying it. This
can easily be done using the
GdkPixbuf library API (the reason this is not done automatically
is that the application will often scale the image anyway according to the
size of the output window, in which case it is much more efficient to only
scale once rather than twice). You can put a videoscale element and a
capsfilter element with
video/x-raw-rgb,pixel-aspect-ratio=(fraction)1/1
caps
in front of this element to make sure the pixbufs always have a 1:1 PAR.
gst-launch -m -v videotestsrc num-buffers=1 ! gdkpixbufsink
Process one single test image as pixbuf (note that the output you see will be slightly misleading. The message structure does contain a valid pixbuf object even if the structure string says '(NULL)').
plugin |
gdkpixbuf |
author |
Tim-Philipp Müller <tim centricular net> |
class |
Sink/Video |
name |
sink |
direction |
sink |
presence |
always |
details |
video/x-raw-rgb, bpp=(int)24, depth=(int)24, endianness=(int)4321, red_mask=(int)16711680, green_mask=(int)65280, blue_mask=(int)255, width=(int)[ 16, 4096 ], height=(int)[ 16, 4096 ], framerate=(fraction)[ 0/1, 2147483647/1 ] |
video/x-raw-rgb, bpp=(int)32, depth=(int)32, endianness=(int)4321, red_mask=(int)-16777216, green_mask=(int)16711680, blue_mask=(int)65280, alpha_mask=(int)255, width=(int)[ 16, 4096 ], height=(int)[ 16, 4096 ], framerate=(fraction)[ 0/1, 2147483647/1 ] |