GStreamer 1.0 element that can save a single frame as a snapshot image from a video stream. This element will can be insterted into a pipeline and it will just pass the video frames on until it's trigger property is set to true. Then it will save a frame and then go back to just passing the video on. It is different from using filesink because it does not terminate the stream, and it can be used to pick off individual frames from a live feed in a simple manner without using a tee.
Properties:
trigger : If true the next frame after the frame delay, is written to an image file.
framedelay : The delay in frames from the trigger to the image save.
filetype : Specify the file type ("bmp", "png" or "jpeg").
location : Specify the file path and filename to write to.
First run autogen.sh $ chmod a+x autogen.sh $ ./autogen.sh This will use autotools to setup the dev environment, and complete with the line: "Now type 'make' to compile this module." You can do that. $ make
$ sudo make install will put install the lo file for use with GStreamer, in /usr/local/lib/gstreamer-1.0 To use this in a pipeline you need to tell gstreamer where to find the .lo file. use: $ export GST_PLUGIN_PATH=/usr/local/lib/gstreamer-1.0
Working: gst-launch-1.0 videotestsrc num-buffers=20 ! snapshotfilter trigger=true framedelay=15 filetype="jpeg" location="image.jpg" ! videoconvert ! xvimagesink
Gstreamer plugin locations: /usr/lib/i386-linux-gnu/gstreamer-1.0 /usr/local/lib/gstreamer-1.0
gst-plugin is a template for writing your own GStreamer plug-in.
The code is deliberately kept simple so that you quickly understand the basics of how to set up autotools and your source tree.
This template demonstrates :
- what to do in autogen.sh
- how to setup configure.ac (your package name and version, GStreamer flags)
- how to setup your source dir
- what to put in Makefile.am
More features and templates might get added later on.
To use it, either make a copy for yourself and rename the parts or use the make_element script in tools. To create sources for "myfilter" based on the "gsttransform" template run:
cd src; ../tools/make_element myfilter gsttransform
This will create gstmyfilter.c and gstmyfilter.h. Open them in an editor and start editing. There are several occurances of the string "template", update those with real values. The plugin will be called 'myfilter' and it will have one element called 'myfilter' too. Also look for "FIXME:" markers that point you to places where you need to edit the code.
You still need to adjust the Makefile.am.