appsrc & appsink usage

[Michael White]

Hi all,


I'm working with GStreamer 1.4.5 on iOS and am having problems with appsrc and appsink.  I'm using appsrc and appsink to pass data between two pipes that work independently; pipelineA will always be playing while pipelineB may change states based on user input, network conditions, etc....  My basis for testing is the following pipeline:



-----------------------------------

    pipeline1 = gst_parse_launch("videotestsrc is-live=true"
                                 " !video/x-raw,format=(string)RGB,width=(int)640,height=(int)480,framerate=(fraction)30/1"
                                 " !videoconvert"
                                 " !autovideosink"
                                 , &error);
    gst_element_set_state(pipeline1, GST_STATE_READY);

-----------------------------------



Obviously I've trimmed down the code from what's there, but this is the essence of it.  I handle the pipeline state change to GST_STATE_READY callback by setting state to GST_STATE_PLAYING.  This works as expected, i.e. I see the test pattern.  What I want to do is create two pipelines and add appsrc & appsink between the two:


-----------------------------------
init()
{
    pipelineA = gst_parse_launch("videotestsrc is-live=true"
                                         " !video/x-raw,format=(string)RGB,width=(int)640,height=(int)480,framerate=(fraction)30/1"
                                         " !appsink name=myappsink"
                                 , &error);
    pipelineB = gst_parse_launch(" appsrc name=myappsrc format=3 is-live=true"
                                         " !videoconvert"
                                         " !autovideosink"
                                         , &error);
    appSink = gst_bin_get_by_name(GST_BIN(pipelinA), "mayappsink");
    memset(&callbacks, 0, sizeof(callbacks));
    callbacks.new_sample = newPacket;
    gst_app_sink_set_callbacks((GstAppSink *)(appSink), &callbacks, NULL, NULL);
    global_appSrc = gst_bin_get_by_name(GST_BIN(pipelineB), "myappsrc");


    gst_element_set_state(pipelineA, GST_STATE_READY);
    gst_element_set_state(pipelineB, GST_STATE_READY);
}


static GstFlowReturn newPacket(GstAppSink *appsink, gpointer data)
{
    static bool firstSample=YES;
    GstFlowReturn retval = GST_FLOW_OK;
    if (gst_app_sink_is_eos(appsink) == FALSE)
    {
        GstSample *sample = gst_app_sink_pull_sample(appsink);
        if (NULL != sample)
        {
            if (YES == firstSample)
            {
                GstCaps *caps = gst_sample_get_caps(sample);
                gst_caps_ref(caps);
                gst_app_src_set_caps((GstAppSrc *)global_appSrc, caps);
                firstSample = NO;
            }
            GstBuffer *buffer = gst_sample_get_buffer(sample);
            if (NULL != buffer)
            {
                if (((GST_STATE_PLAYING == global_pipelineBState) || (GST_STATE_PAUSED == global_pipelineBState)))
                {
                    retval = gst_app_src_push_buffer((GstAppSrc *)global_appSrc, gst_buffer_ref(buffer));
	            NSLog(@"retval = %d", retval);
                 }
            }
            gst_sample_unref(sample);
        }
    }


    return retval;
}

------------------------------------------------------


Again, I've trimmed the code quite a bit but I believe all the important bits are there.  As before, I handle the pipeline state changes to GST_STATE_READY callback by setting the states to GST_STATE_PLAYING.


This pair of pipelines do not work.  "not work" means I see no errors (I am registering for error, eos, state-changed, and clock-lost callbacks) but I also see no test pattern, just a blank screen.  I see the samples and buffers being handled by newPacket(), as there is a continuous stream of debug output.  I've tried various permutations, including adding the same caps line in pipleineB, i.e.:



------------------------------------------------------

    pipelineB = gst_parse_launch(" appsrc name=myappsrc format=3 is-live=true"

                                         " !video/x-raw,format=(string)RGB,width=(int)640,height=(int)480,framerate=(fraction)30/1"

                                         " !videoconvert"
                                         " !autovideosink"
                                         , &error);

------------------------------------------------------



But I get the same results: no error but also no video.


Any thoughts on what I'm doing wrong here?


Thanks,
Michael

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/gstreamer-devel/attachments/20150508/fe777de0/attachment.html>