[gst-devel] How to send data to next elemnet before calling _chain()

[Chen, Weian]

Hi,

I have another question, could you help to answew:

In your code, for stream->caps, whose caps is it?

thanks,
Weian
________________________________
From: sudarshan bisht [mailto:bisht.sudarshan at gmail.com]
Sent: 2009年8月20日 12:32
To: Discussion of the development of GStreamer
Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain()

      Hi  ,
             I think you can send such extradata using caps .

So on demuxer side do :---

           GstBuffer *=buf;

            buf = gst_buffer_new_and_alloc (size);

            memcpy (GST_BUFFER_DATA (buf), the data u want to pass as an extradata (should be guint8*) , size);

           gst_caps_set_simple (stream->caps,"codec_data", GST_TYPE_BUFFER, buf, NULL);

           gst_buffer_unref (buf);
 On Decoder side in _setcaps function u can do :----


        GstBuffer    *codec_data = NULL;

         guint8* extradata =NULL;

        capStruct = gst_caps_get_structure(caps,0);

       /* Read extra data passed via demuxer. */
        value = gst_structure_get_value(capStruct, "codec_data");

        codec_data = gst_value_get_buffer(value);

        extradata =GST_BUFFER_DATA(codec_data);

        // now u can parse extradata to get your fields .


2009/8/20 Chen, Weian <weian.chen at intel.com<mailto:weian.chen at intel.com>>

The data I want to send is couple of bytes (some information of current element)  which will be used in next element's _setcap() funct. So we could not wait the gst_pad_push() function to send.

thanks,
Weian
-----Original Message-----
From: Michael Smith [mailto:msmith at xiph.org<mailto:msmith at xiph.org>]
Sent: 2009年8月20日 1:35
To: Discussion of the development of GStreamer
Subject: Re: [gst-devel] How to send data to next elemnet before calling _chain()

On Wed, Aug 19, 2009 at 4:41 AM, Chen, Weian<weian.chen at intel.com<mailto:weian.chen at intel.com>> wrote:
> Hi All,
>
> I need to send some data to the next element before calling the _chain
> function (such as send the data from src element to encoder element), does
> it possible?

Can you explain in a bit more detail what you want to do?

You normally should call gst_pad_push() to send data to the next
element in your pipeline - but that calls the chain function in that
next element, so it sounds like you're asking for something different?

What data do you want to send? Why do you want to avoid calling the
chain function when sending this data?

Mike

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--
Regards,

Sudarshan Bisht
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