On Fri, Nov 25, 2016 at 10:56:55AM +0000, Mahendran, Dandapani (D.) wrote: > Hello Darwish, > > Thank you for your response. > > I have attached the gst & pulseaudio logs with time stamps. > Audio is played with delay and breaks/cut. > > Also, attaching the pulseaudio log taken by running "extended-test.c", that > streams the audio through same sink (route_andautonav). During this testing with > extended-test.c, audio is streamed properly without any delay/break/cut. So the > problem seems more oriented towards gstreamer and pulsesink plugin. > Yeah, from the gstreamer log there's a lot of instances of: 0:02:42.130359686 gst_pulsering_stream_request_cb: got request for length 17640 0:02:42.130592686 gst_pulsering_stream_underflow_cb: Got underflow ... 0:02:51.930305021 gst_pulsering_stream_request_cb: got request for length 9526 0:02:51.930489354 gst_pulsering_stream_underflow_cb: Got underflow ... 0:02:54.775065355 gst_pulsering_stream_request_cb: got request for length 9702 0:02:54.775288355 gst_pulsering_stream_underflow_cb: Got underflow ... So pulse _is doing its job_ and asks for the stream to be filled through the stream's write callback. Meanwhile gstreamer does not provide it anything in return -- triggering an underrun. So the question is, why gstreamer is not fulfilling the requests? Looking at gstreamer's pulsesink code [1], it seems the stream write callback only fulfills the request and signals the PA mainloop if there's an in-commit buffer with appropriate length. So either there's a bug in the sink's handling of the mainloop, or the gstreamer source is not providing audio at appropriate speed. PS. The attached "extended-test.c" coding is misusing pulse's stream underflow and stream ready callbacks. Check pacat source code for the more appropriate handling. PSS. From the attached pulse logs, you're creating a BIG number of streams at once. This triggers __a lot of__ rewinds for existing streams playing audio and increases the the possibility of cracks and server misbehavior [2] Regards, [1] https://github.com/GStreamer/gst-plugins-good/blob/master/ext/pulse/pulsesink.c , gst_pulsering_stream_request_cb() [2] https://github.com/a-darwish/malicious-pulseaudio-clients/blob/master/kill_server_quickly_open_write_streams.c -- Darwish http://darwish.chasingpointers.com
