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Added doc for xvimagesink.

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Original commit message from CVS:
2005-11-26  Julien MOUTTE  <julien@moutte.net>

* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-base-plugins-docs.sgml:
* docs/plugins/gst-plugins-base-plugins-sections.txt:
* sys/xvimage/xvimagesink.c: Added doc for xvimagesink.
This commit is contained in:
Julien Moutte 2005-11-26 15:26:36 +00:00
parent f663c82d02
commit c5a52004e0
5 changed files with 118 additions and 1 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2005-11-26 Julien MOUTTE <julien@moutte.net>
* docs/plugins/Makefile.am:
* docs/plugins/gst-plugins-base-plugins-docs.sgml:
* docs/plugins/gst-plugins-base-plugins-sections.txt:
* sys/xvimage/xvimagesink.c: Added doc for xvimagesink.
2005-11-26 Julien MOUTTE <julien@moutte.net>
* docs/plugins/Makefile.am:

3
docs/plugins/Makefile.am
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@ -85,7 +85,8 @@ EXTRA_HFILES = \
$(top_srcdir)/gst/tcp/gsttcpserversink.h \
$(top_srcdir)/gst/videotestsrc/gstvideotestsrc.h \
$(top_srcdir)/gst/volume/gstvolume.h \
$(top_srcdir)/sys/ximage/ximagesink.h
$(top_srcdir)/sys/ximage/ximagesink.h \
$(top_srcdir)/sys/xvimage/xvimagesink.h
# Images to copy into HTML directory.
HTML_IMAGES =

1
docs/plugins/gst-plugins-base-plugins-docs.sgml
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@ -25,6 +25,7 @@
<xi:include href="xml/element-volume.xml" />
<xi:include href="xml/element-vorbisenc.xml" />
<xi:include href="xml/element-ximagesink.xml" />
<xi:include href="xml/element-xvimagesink.xml" />
</chapter>
<chapter>

8
docs/plugins/gst-plugins-base-plugins-sections.txt
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@ -95,6 +95,14 @@ GstXImageSink
GstXImagesSinkClass
</SECTION>
<SECTION>
<FILE>element-xvimagesink</FILE>
<TITLE>xvimagesink</TITLE>
GstXvImageSink
<SUBSECTION Standard>
GstXvImagesSinkClass
</SECTION>
<SECTION>
<FILE>private</FILE>

100
sys/xvimage/xvimagesink.c
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@ -17,6 +17,106 @@
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:element-xvimagesink
*
* <refsect2>
* <para>
* XvImageSink renders video frames to a drawable (XWindow) on a local display
* using the XVideo extension. Rendering to a remote display is theorically
* possible but i doubt that the XVideo extension is actually available when
* connecting to a remote display. This element can receive a Window ID from the
* application through the XOverlay interface and will then render video frames
* in this drawable. If no Window ID was provided by the application, the
* element will create its own internal window and render into it.
* </para>
* <title>Scaling</title>
* <para>
* The XVideo extension, when it's available, handles hardware accelerated
* scaling of video frames. This means that the element will just accept
* incoming video frames no matter their geometry and will then put them to the
* drawable scaling them on the fly. Using the
* <link linkend="GstXvImageSink--force-aspect-ratio">force-aspect-ratio</link>
* property it is possible to enforce scaling with a constant aspect ratio,
* which means drawing black borders around the video frame.
* </para>
* <title>Events</title>
* <para>
* XvImageSink creates a thread to handle events coming from the drawable. There
* are several kind of events that can be grouped in 2 big categories: input
* events and window state related events. Input events will be translated to
* navigation events and pushed upstream for other elements to react on them.
* This includes events such as pointer moves, key press/release, clicks etc...
* Other events are used to handle the drawable appearance even when the data
* is not flowing (GST_STATE_PAUSED). That means that even when the element is
* paused, it will receive expose events from the drawable and draw the latest
* frame with correct borders/aspect-ratio.
* </para>
* <title>Pixel aspect ratio</title>
* <para>
* When changing state to GST_STATE_READY, XvImageSink will open a connection to
* the display specified in the
* <link linkend="GstXvImageSink--display">display</link> property or the
* default display if nothing specified. Once this connection is open it will
* inspect the display configuration including the physical display geometry and
* then calculate the pixel aspect ratio. When receiving video frames with a
* different pixel aspect ratio, XvImageSink will use hardware scaling to
* display the video frames correctly on display's pixel aspect ratio.
* Sometimes the calculated pixel aspect ratio can be wrong, it is
* then possible to enforce a specific pixel aspect ratio using the
* <link linkend="GstXvImageSink--pixel-aspect-ratio">pixel-aspect-ratio</link>
* property.
* </para>
* <title>Examples</title>
* <para>
* Here is a simple pipeline to test hardware scaling :
* <programlisting>
* gst-launch -v videotestsrc ! xvimagesink
* </programlisting>
* When the test video signal appears you can resize the window and see that
* video frames are scaled through hardware (no extra CPU cost). You can try
* again setting the force-aspect-ratio property to true and observe the borders
* drawn around the scaled image respecting aspect ratio.
* <programlisting>
* gst-launch -v videotestsrc ! xvimagesink force-aspect-ratio=true
* </programlisting>
* </para>
* <para>
* Here is a simple pipeline to test navigation events :
* <programlisting>
* gst-launch -v videotestsrc ! navigationtest ! xvimagesink
* </programlisting>
* While moving the mouse pointer over the test signal you will see a black box
* following the mouse pointer. If you press the mouse button somewhere on the
* video and release it somewhere else a green box will appear where you pressed
* the button and a red one where you released it. (The navigationtest element
* is part of gst-plugins-good.) You can observe here that even if the images
* are scaled through hardware the pointer coordinates are converted back to the
* original video frame geometry so that the box can be drawn to the correct
* position. This also handles borders correctly, limiting coordinates to the
* image area
* </para>
* <para>
* Here is a simple pipeline to test pixel aspect ratio :
* <programlisting>
* gst-launch -v videotestsrc ! video/x-raw-yuv, pixel-aspect-ratio=(fraction)4/3 ! xvimagesink
* </programlisting>
* This is faking a 4/3 pixel aspect ratio caps on video frames produced by
* videotestsrc, in most cases the pixel aspect ratio of the display will be
* 1/1. This means that XvImageSink will have to do the scaling to convert
* incoming frames to a size that will match the display pixel aspect ratio
* (from 320x240 to 320x180 in this case). Note that you might have to escape
* some characters for your shell like '\(fraction\)'.
* </para>
* <para>
* Here is a test pipeline to test the colorbalance interface :
* <programlisting>
* gst-launch -v videotestsrc ! xvimagesink hue=100 saturation=-100 brightness=100
* </programlisting>
* </para>
* </refsect2>
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif