Media type probing

[Sergey Yakimenko-2]

Hello all,

I wonder if there is a way to determine whether there are gstreamer elements
in a certain gstreamer configuration on a certain system that support certain
media type? In other words, if there is a mechanism, or a way to implement
such a mechanism similar to DirectShow's IGraphBuilder::Render() or
IFilterGraph2::RenderEx() functions? I now that there is a way of recognizing
media type - decodebin, etc.; but I need to do the opposite operation: I have
a media stream with fully specified mediatype, and I'd like to know whether I
can play the stream, but to know this before I start playing, i.e. without
playing the stream.

I would be highly appreciate for any advice.


Sergey Yakimenko




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[michael smith-6-3]

On Wed, Dec 24, 2008 at 3:49 AM, Sergey Yakimenko <[hidden email]> wrote:

> Hello all,
>
> I wonder if there is a way to determine whether there are gstreamer elements
> in a certain gstreamer configuration on a certain system that support certain
> media type? In other words, if there is a mechanism, or a way to implement
> such a mechanism similar to DirectShow's IGraphBuilder::Render() or
> IFilterGraph2::RenderEx() functions? I now that there is a way of recognizing
> media type - decodebin, etc.; but I need to do the opposite operation: I have
> a media stream with fully specified mediatype, and I'd like to know whether I
> can play the stream, but to know this before I start playing, i.e. without
> playing the stream.

Yes, this is basically what decodebin does internally - it uses a
typefind element to find out what type of media it is, then iterates
over the element factories to find a compatible decoder/demuxer.

You can look at the code for that to figure out the details of how to do it.

Mike

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[Sergey Yakimenko-2]

Michael,

Thanks for your reply. You're right - it seems that decodebin does exactly
what I need. I wonder why this didn't occur to me before. Thank you.


--
Best regards,
Sergey Yakimenko               [hidden email]
software developer of ApriorIT - A PriorITy Choice!



-----Original Message-----
From: Michael Smith
Sent: Wednesday, December 24, 2008 8:41:10 PM
To: Sergey Yakimenko
CC:  
Subject: [gst-devel] Media type probing

MS> On Wed, Dec 24, 2008 at 3:49 AM, Sergey Yakimenko <[hidden email]> wrote:

>> Hello all,
>>
>> I wonder if there is a way to determine whether there are gstreamer elements
>> in a certain gstreamer configuration on a certain system that support certain
>> media type? In other words, if there is a mechanism, or a way to implement
>> such a mechanism similar to DirectShow's IGraphBuilder::Render() or
>> IFilterGraph2::RenderEx() functions? I now that there is a way of recognizing
>> media type - decodebin, etc.; but I need to do the opposite operation: I have
>> a media stream with fully specified mediatype, and I'd like to know whether I
>> can play the stream, but to know this before I start playing, i.e. without
>> playing the stream.

MS> Yes, this is basically what decodebin does internally - it uses a
MS> typefind element to find out what type of media it is, then iterates
MS> over the element factories to find a compatible decoder/demuxer.

MS> You can look at the code for that to figure out the details of how to do it.

MS> Mike





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