I am working at a player based on gstreamer tutorials. For this I created a pipeline using: 

pipeline	= gst_pipeline_new("audio-player");

//adding also 3 gstreamer elements
appsrc		= gst_element_factory_make("appsrc", "source");
decoder		= gst_element_factory_make("faad", "aac-decoder");
sink		= gst_element_factory_make("autoaudiosink", "audio-output");

//adding and linking the elements to the pipeline
gst_bin_add_many (GST_BIN (pipeline), appsrc, decoder, sink, NULL);
gst_element_link_many(appsrc, decoder,sink, NULL);

//for appsrc was added a callback function need_data_cb
g_signal_connect(appsrc, "need-data", (GCallback)need_data_cb, data);

//state of pipeline is set to playing
gst_element_set_state(pipeline, GST_STATE_PLAYING);

In need_data_cb function I have a buffer that I want to be played: 

g_signal_emit_by_name(appsrc, "push-buffer", buffer, &ret);

My poblem is this: I have the same code in Linux and in Android. In Linux buffer is played well each time it enters the callback function need_data_cb. In Android it plays the buffer just the first time it enters in need_data_cb and after that no sound. Why it happens this when I have same code in both versions. If I add in need_data_cb Android version to change pipeline states to pause and play before adding buffer to appsrc, it plays each time buffer but with some interruptions between each call. 

//the first 2 lines added in Android version to play each time buffer
gst_element_set_state(pipeline, GST_STATE_PAUSED);
gst_element_set_state(pipeline, GST_STATE_PLAYING);
g_signal_emit_by_name(appsrc, "push-buffer", buffer, &ret);

The question is why on Linux works fine without these lines and on Android not?
On Linux I installed gstreamer 0.10 version, and on Android I used the libs from gstreamer sdk tutorials. Is there any difference between them? 

Thanks,
Radu