[gst-devel] help wrt loading the gstreamer plugins

[Deeptendu Bikash]

Hi Pavan,

I am also relatively new to GStreamer but using it for a month now. Here is
what I would suggest you to do:

(a) The best way to understand whats going on behind the scene is to go
through the debug level log messages. For example: gst-launch --gst-debug=5
--gst-debug-no-color filesrc location=<...> ! <demuxer> ! <decoder> ! <sink>
2>/tmp/out. Quit the pipeline forcefully after a second since the generated
log will be huge. It however pays to go through the pain of going through
the huge log in /tmp/out.

(b) The best way to understand decodebin is to go through the decodebin
code. It is easy to understand, and there is also an explanation given in
the README file in the gst-plugins-base/gst/playback directory.

Hope this would help in you in getting some answers for 1. I do not have a
good knowledge on 2 and would myself wait for answers from seasoned gst
developers.

Regards,
Deeptendu

On 9/5/06, Pavan Krishnamurthy <2pavan at gmail.com> wrote:
>
>  Hi,
>
>
>
> This is my first mail to this group. I have been working on gstreamer
> since a few days. Read most of the docs and experimented few things like
> writing new audio sink plugin.
>
>
>
> But I am not very much clear about some of the concepts. Can anybody
> explain me on the following?
>
>
>
>    1. Typefind and autoplugging :
>
>  I wanted to know how a media player application builds a pipeline by
> itself, just by the media filename. Does the gstreamer loads all the plugins
> in the GST_PLUGIN_PATH whenever gstreamer is initialized? If not when will
> it load the exact plugin required to handle a particular media type.
>
> In the docs, it is written that, gstreamer uses a typefind element which
> iterates through all the plugins which implement typefind functionality. And
> when a plugin which can handle that media is found, it emits a signal. So
> does it mean that to load a plugin to handle a particular format, all the
> plugins in the system needs to be loaded? If not how can the typefind
> function of a plugin be called without loading it?
>
>
>
> Also I read about the elements "playbin" and "decodebin". Do these
> elements help the application to build the pipeline dynamically? If so what
> mechanism do they use to build the pipeline?
>
>
>
>    1. XML and Registry in gstreamer:
>
> In the docs it is written that XML is used internally to manage the plugin
> registry. The plugin registry is a file that contains the definition of all
> the plugins GStreamer knows about to have quick access to the specifics of
> the plugins.
>
>
>
> When is this registry.xml file generated first time? And how is it
> generated? How is this file used in gstreamer? Is it used for loading
> plugins dynamically?
>
>
>
> Thanks in advance for any sort of help.
>
> Regards,
>
> Pavan
>
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