Transcoding support

[Alex Lee-5]

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?

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

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?

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?


Please correct me if there are any errors. I completely new to GStreamer.

Thanks,
Alex

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[Stefan Sauer]

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
> [hidden email]
> https://lists.sourceforge.net/lists/listinfo/gstreamer-devel

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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
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gstreamer-devel mailing list
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