It sounds like you do something wrong. The things you describe are perfectly normal when you don't push enough data fast enough in appsrc.

What are pushing in appsrc? Where does the data come from? Your example would suggest it's a live source but you don't have appsrc configured as a live source? Is the data you push timestamped? 

It's also likely that you want to configure caps on the appsrc...

           Thanks for your attention.

         I had user such codes set appsrc caps.

         GstCaps *caps = gst_caps_from_string("video/x-raw-rgb, width=(int)176, height=(int)144, framerate=(fraction)25/2, bpp=(int)16, depth=(int)16, red_mask=(int)63488, green_mask=(int)2016, blue_mask=(int)31, endianness=(int)1234");
     gst_app_src_set_caps(GST_APP_SRC(v_src), caps);

   And after run the pipe , I write video/x-raw-rgb data in another thread which create by g_thread_create. The thread will push data to appsrc .

do
{
    .....
    buf = gst_app_buffer_new(tmpbuf, size, gst_app_buf_free, tmpbuf);
    gst_app_src_push_buffer(GST_APP_SRC (v_src), buf);
    ....
}while(1)

 And the pipeline could work good if I only codec video info. 
 
timestamp, I don't konw how to deal it now.  May be question is here, I will study it with fast,   But can you tell me more about it?

                                                                                                                    thank you very much!

can you check the return value of gst_app_src_push_buffer() ?

thanks you result.

There days I try to find out , where is worg, but i am failed. 

But I see gst_app_src_push_buffer result are GST_FLOW_OK. Please such pipeline , it stilln't work good.

static gboolean write_frame(GstElement* appsrc)
{
    GstBuffer *buf;
    GstFlowReturn ret;
    char tmpbuf[176*144*2] = {0};
    buf = gst_app_buffer_new(tmpbuf, 176*144*2, gst_app_buf_free, tmpbuf);
    if( (ret = gst_app_src_push_buffer(GST_APP_SRC (appsrc), buf) )!= GST_FLOW_OK)
    {
        printf("gst_buf push data error value is %d  \n", ret);
    }
    else
    {
        printf("gst buf pust data ok\n");
    }
    return TRUE;
}
static gpointer camera_capture_thread(gpointer data)
{
    do
    {
        if(g_quit)
        {
            break;
        }
        write_frame(data);
        usleep(200000);
    }while(1);

    g_thread_exit(NULL);
}

int main(int argc, char** argv)
{
    GMainLoop *mainloop;
    GstElement* pipeline;

    g_type_init();
    g_thread_init(NULL);
    gst_init(&argc, &argv);

   pipeline = gst_parse_launch("appsrc name=v_src ! ffmpegcolorspace ! ffenc_h263 name=v_enc ! ffmux_3gp name=mux location=test.3gp alsasrc name=a_src !  audio/x-raw-int,channels=1,rate=8000 ! audioresample ! amrnbenc name=a_enc  a_enc. ! mux. mux. ! filesink location=test.3gp", NULL);

    GstElement* v_src = gst_bin_get_by_name(GST_BIN(pipeline), "v_src");
    GstElement* a_src = gst_bin_get_by_name(GST_BIN(pipeline), "a_src");
    GstCaps* caps = gst_caps_from_string("video/x-raw-rgb, width=(int)176, height=(int)144, framerate=  (fraction)25/2, bpp=(int)16, depth=(int)16, red_mask=(int)63488, green_mask=(int)2016, blue_mask=(int)31,endianness=(int)1234");

    gst_app_src_set_caps(GST_APP_SRC(v_src), caps);
    if(gst_element_set_state (pipeline, GST_STATE_PLAYING) == GST_STATE_CHANGE_FAILURE)
    {
    }

    GThread* capture_thread = g_thread_create(camera_capture_thread, v_src, TRUE, NULL);

    sleep(10);
    g_quit = 1;

  if(gst_element_set_state (GST_ELEMENT(a_src), GST_STATE_NULL) == GST_STATE_CHANGE_FAILURE)
    {
    }
    gst_app_src_end_of_stream(GST_APP_SRC(v_src));
    if(gst_element_set_state (GST_ELEMENT(v_src), GST_STATE_NULL) == GST_STATE_CHANGE_FAILURE)
    {

    }

    if(gst_element_set_state (GST_ELEMENT(pipeline), GST_STATE_NULL) == GST_STATE_CHANGE_FAILURE)
    {

    }

    gst_element_get_state(pipeline, NULL, NULL, GST_CLOCK_TIME_NONE);

}


I run this programe , I found I only get audio data, at sleep time.   and i could get appsrc data untill gst_element_set_state (GST_ELEMENT(a_src), GST_STATE_NULL) 
is do.

THANK YOU VERY MUCH. 

I found if i make appsrc with attribute "do-timestamp=true format=3" It works good.