gstreamer/docs/manual/goals.xml
Andy Wingo 70cfc6cb4d new parser that uses flex and bison
Original commit message from CVS:
* new parser that uses flex and bison
- doesn't do dynamic pipelines yet...
* added GErrors to the gst_parse_launch[v] api
* added --gst-mask-help command line option
* fixed -o option for gst-launch
* GstElement api change:
- gst_element_get_pad
- gst_element_get_request_pad, gst_element_get_static_pad
- gst_element_get_compatible_pad
- gst_element_get_compatible_static_pad, gst_element_get_compatible_request_pad
- gst_element_[dis]connect -> gst_element_[dis]connect_pads
- gst_element_[dis]connect_elements -> gst_element_[dis]connect
* manual update
* example, tool, and doc updates for the api changes
- no more plugin docs in the core docs, plugins require a more
extensive doc system
2002-04-07 23:32:16 +00:00

129 lines
4 KiB
XML

<chapter id="cha-goals">
<title>Goals</title>
<para>
GStreamer was designed to provide a solution to the current Linux media
problems.
</para>
<sect1 id="sec-goals-design">
<title>The design goals</title>
<para>
We descibe what we try to achieve with GStreamer.
</para>
<sect2 id="sec-goals-clean">
<title>Clean and powerfull</title>
<para>
GStreamer wants to provide a clean interface to:
</para>
<itemizedlist>
<listitem>
<para>
The application programmer who wants to build a media pipeline.
The programmer can use an extensive set of powerfull tools to create
media pipelines without writing a single line of code. Performing
complex media manipulations becomes very easy.
</para>
</listitem>
<listitem>
<para>
The plugin programmer. Plugin programmers are provided a clean and
simple API to create self contained plugins. An extensive debugging
and tracing mechanism has been integrated. GStreamer also comes with
an extensive set of real-life plugins that serve as an example too.
</para>
</listitem>
</itemizedlist>
</sect2>
<sect2 id="sec-goals-object">
<title>Object oriented</title>
<para>
Adhere to the GLib 2.0 object model. A programmer familiar with GLib 2.0 or older versions
of Gtk+ will be comfortable with GStreamer.
</para>
<para>
GStreamer uses the mechanism of signals and object properties.
</para>
<para>
All objects can be queried at runtime for their various properties and
capabilities.
</para>
</sect2>
<sect2 id="sec-goals-extensible">
<title>Extensible</title>
<para>
All GStreamer Objects can be extended using the GObject inheritance methods.
</para>
<para>
All plugins are loaded dynamically and can be extended and upgraded
independently.
</para>
</sect2>
<sect2 id="sec-goals-binary">
<title>Allow binary only plugins</title>
<para>
Plugins are shared libraries that are loaded at runtime. Since all the properties of the
plugin can be set using the GObject properties, there is no need (and in fact no way) to
have any header files installed for the plugins.
</para>
<para>
Special care has been taking into making the plugin completely self
contained. All relevant aspects of plugins can be queried at run-time.
</para>
</sect2>
<sect2 id="sec-goals-performance">
<title>High performance</title>
<para>
High performance is obtained by:
</para>
<itemizedlist>
<listitem>
<para>
Using GLib g_mem_chunk where possible to minimize dynamic memory
allocation.
</para>
</listitem>
<listitem>
<para>
Extremely light-weight connections between plugins. Data can travel
the pipeline with minimal overhead.
</para>
</listitem>
<listitem>
<para>
Providing a mechanism to directly work on the target memory. A plugin can for example
directly write to the X server's shared memory space. Buffers can also point to
arbitrary memory, such as a sound card's internal hardware buffer.
</para>
</listitem>
<listitem>
<para>
Refcounting and copy on write minimize usage of memcpy(3).
Sub-buffers efficiently split buffers into manageable pieces.
</para>
</listitem>
<listitem>
<para>
The use of cothreads to minimize the threading overhead. Cothreads are a simple and fast
user-space method for switching between subtasks.
</para>
</listitem>
<listitem>
<para>
Allowing HW acceleration by the use of specialized plugins.
</para>
</listitem>
<listitem>
<para>
Using a plugin registry with the specifications of the plugins so
that the plugin loading can be delayed until the plugin is actually
used.
</para>
</listitem>
</itemizedlist>
</sect2>
</sect1>
</chapter>