使用Appsrc Appsink时出错

rb1:3231): GStreamer-CRITICAL **: gst_caps_get_structure: assertion `index < caps->structs->len’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_has_field: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_fixate_field_nearest_fraction: assertion `gst_structure_has_field (structure,field_name)’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_get_fraction: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_has_field: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_has_field: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_has_field: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_structure_has_field: assertion `structure != NULL’ failed

(rb1:3231): GStreamer-CRITICAL **: gst_pad_set_caps: assertion `caps == NULL || gst_caps_is_fixed (caps)’ failed

** ERROR **: not negotiated
aborting…
Aborted

任何帮助,将不胜感激.

作为参考,我已经给出了代码(我还没有实现OpenCV部分)：

#include <gst/gst.h>
#include <gst/app/gstappsrc.h>
#include <gst/app/gstappbuffer.h>
#include <gst/app/gstappsink.h>
#include <gst/gstbuffer.h>
#include <stdbool.h>
#include <stdio.h>

static GMainLoop *loop;
GstBuffer *buffer;
GstAppSinkCallbacks callbacks;
GstElement *pipeline_in;
GstElement *pipeline_out;
GstBus *bus;
GError *error;
const char app_sink_name[] = "app-sink";
const char app_src_name[] = "app-src";
const char pipeline_in_str[500];
const char pipeline_out_str[500];

static gboolean bus_call(GstBus * bus,GstMessage * msg,void *user_data)
{
    gchar *userdata = (gchar *) user_data;
    switch (GST_MESSAGE_TYPE(msg)) {
    case GST_MESSAGE_EOS:{
            //sender check - pipeline1 sends a EOS msg to AppSrc in pipeline2
            if (g_ascii_strcasecmp(userdata,gst_element_get_name(pipeline_in)) == 0) {
                g_print("EOS detected (%s)n",userdata);
                gst_app_src_end_of_stream(GST_APP_SRC(gst_bin_get_by_name(GST_BIN(pipeline_out),app_src_name)));
            }
            //sender check - when pipeline2 sends the EOS msg,quite.
            if (g_ascii_strcasecmp(userdata,gst_element_get_name(pipeline_out)) == 0) {
                g_print("Finished playback (%s)n",userdata);
                g_main_loop_quit(loop);
            }
            break;
        }
    case GST_MESSAGE_ERROR:{
            GError *err;
            gst_message_parse_error(msg,&err,NULL);
            g_error("%s",err->message);
            g_error_free(err);

            g_main_loop_quit(loop);
            break;
        }
    default:
        break;
    }

    return true;
}

GstFlowReturn newbuffer(GstAppSink * app_sink,gpointer user_data)
{
    GstBuffer *buffer = gst_app_sink_pull_buffer((GstAppSink *) gst_bin_get_by_name(GST_BIN(pipeline_in),app_sink_name));
    gst_app_src_push_buffer(GST_APP_SRC(gst_bin_get_by_name(GST_BIN(pipeline_out),app_src_name)),buffer);
    return GST_FLOW_OK;
}

int main(int argc,char *argv[])
{
    int result;
    gst_init(&argc,&argv);
    loop = g_main_loop_new(NULL,FALSE);

    pipeline_in = gst_pipeline_new("my_pipeline");
    pipeline_out = gst_pipeline_new("my_pipeline2");
    //result=sprintf(pipeline_in_str,"udpsrc port=5000 ! video/x-h264,width=(int)640,height=(int)480,framerate=(fraction)30/1,pixel-aspect-ratio=(fraction    )1/1,codec_data=(buffer            )0142c01effe100176742c01e92540501ed8088000003000bb9aca00078b17501000468ce3c80,stream-format=(string)avc,alignment=(string)au ! ffdec_h264 ! video/x-raw-yuv,width=640,height=480 ! ffmpegcolorspace ! video/x-raw-rgb,height=480 !   ffmpegcolorspace ! appsink name="%s"",app_sink_name);
    result = sprintf(pipeline_in_str,"videotestsrc ! video/x-raw-rgb,height=480     ! ffmpegcolorspace ! appsink name=%s",app_sink_name);
    printf("First pipeline string nn%sn",pipeline_in_str);
    pipeline_in = gst_parse_launch(pipeline_in_str,&error);
    if (error) {
        g_printerr("Error in first pipeline: %sn",error->message);
        return -1;
    }
    result = sprintf(pipeline_out_str,"appsrc name=%s ! queue ! videoparse format=14    width=640 height=480 ! videorate ! videoscale ! ffmpegcolorspace ! video/x-        raw-rgb,height=480 ! xvimagesink",app_src_name);
    printf("Second pipeline stringnn%sn",pipeline_out_str);
    pipeline_out = gst_parse_launch(pipeline_out_str,error->message);
        return -1;
    }

    bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline_in));
    gst_bus_add_watch(bus,bus_call,NULL);
    gst_object_unref(bus);
    bus = gst_pipeline_get_bus(GST_PIPELINE(pipeline_out));
    gst_bus_add_watch(bus,NULL);
    gst_object_unref(bus);
    gst_element_set_state(GST_ELEMENT(pipeline_in),GST_STATE_PLAYING);
    gst_element_set_state(GST_ELEMENT(pipeline_out),GST_STATE_PLAYING);

    callbacks.eos = NULL;
    callbacks.new_preroll = NULL;
    callbacks.new_buffer = newbuffer;
    gst_app_sink_set_callbacks((GstAppSink *) gst_bin_get_by_name(GST_BIN(pipeline_in),app_sink_name),&callbacks,NULL,NULL);

    g_main_loop_run(loop);
    gst_element_set_state(GST_ELEMENT(pipeline_in),GST_STATE_NULL);
    gst_element_set_state(GST_ELEMENT(pipeline_out),GST_STATE_NULL);
    gst_object_unref(GST_OBJECT(pipeline_in));
    gst_object_unref(GST_OBJECT(pipeline_out));
    return 0;
}

/* indented using http://indentcode.net/ */