[gst-devel] Transcoding support

[Stefan Kost]

Alex Lee schrieb:
> Hi All,
> 
> I want to add a new decoder and encoder plugin for a new video std to
> GStreamer, in order to
> transcode some Theora/Vorbis/OGG media file to <New video
> std>/Vorbis/OGG files and play
> the transcoded media file.
> 
> What I learned now is I should wirte two plugins (decoder and encoder
> plugins) as Plugin
> Writer's Guide tells. But this is a new video coding std, and GStreamer
> don't have a MIME
> type for this kind of stream. Does any one knows how to add a new MIME
> type to GStreamer?

gstreamer uses media types, while they look similar to mime types its an own
domain. if you need a new media-type, you just use it.

> 
> Also I want to know how to keep synchronized in GStreamer during the
> transcoding process,
> should I worry about that?

all elements in the same pipeline are syncronized to the same clock.

> 
> Another question is how to install/registry my plugin to GSteamer. So
> that I can use my plugin
> to creat a pipleline using gst-launch to do the transcoding work. Does
> GStreamer can load and
> use my plugin from another shared library?

Have a look at the API docs, first chapter "Running GStreamer Applications".
There is no need to register it, just place it in the right directory.

> 
> I'm also confused by gst-launch parameter list format:
> 
>      example% gst-launch sunaudiosrc !
> 'audio/x-raw-int,rate=[32000,64000],width
> =[16,32],depth={16,24,32},signed=(boolean)true' ! wavenc ! filesink
> location=rec
> ording.wav
> 
>      example% gst-launch filesrc location=videofile ! decodebin
> name=decoder dec
> oder. ! queue ! audioconvert ! audioresample ! osssink decoder. !
> ffmpegcolorspa
> ce ! xvimagesink
> 
> Why there is a ! between "sunaudiosrc" and its properties and what the
> meaning of the "." after
> "osssink decoder". Does any one knows some pointers talking the format
> and their real meaning?

Have you discovered the man page fro gst-launch yet? The stuff after sunaudiosrc
are not parameters - its an implicit caps-filter element. The "osssink" is the
end of a pipeline part and "decoder." specifies an yet unliked pad from
decodebin (see name="decoder") as a start of a pipeline fragemnt. Remeber that
gstreamer pipelines are actually graphs and not just a sequence of elements.

> 
> 
> Please correct me if there are any errors. I completely new to GStreamer.
> 
> Thanks,
> Alex
> 
> 
> ------------------------------------------------------------------------
> 
> ------------------------------------------------------------------------------
> Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are
> powering Web 2.0 with engaging, cross-platform capabilities. Quickly and
> easily build your RIAs with Flex Builder, the Eclipse(TM)based development
> software that enables intelligent coding and step-through debugging.
> Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> gstreamer-devel mailing list
> gstreamer-devel at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel