[gst-devel] Timestamping problem with gdppay element

4ernov 4ernov at gmail.com
Tue Nov 23 09:20:56 CET 2010


Hello, Marco,

thanks for answer.
> Hi,
>
> On Tue, Nov 16, 2010 at 5:19 PM, 4ernov <4ernov at gmail.com> wrote:
> > Hello,
> >
> > I continue working at some complex pipeline which I wrote about
> > previously ("Problems with video, tee and queues"). Solution proposed
> > by Marco works just fine for the pipeline I noticed there:
> >
> >                     queue -- xvimagesink
> >                  /
> > playbin -- tee
> >                  \
> >                    queue -- fakesink
> >
> > converted dynamically to:
> >
> >                     queue -- xvimagesink
> >                  /
> > playbin -- tee
> >                  \
> >                     queue -- xvimagesink
> >
> > But the final destination of my experiments is the following case:
> >
> >
> >                     queue -- xvimagesink
> >                  /
> > playbin -- tee
> >                  \
> >                    queue -- fakesink
> >
> > converted dynamically to:
> >
> >                     queue -- xvimagesink
> >                  /
> > playbin -- tee
> >                  \
> >                     queue -- gdppay -- filesink
> >
> > with remote end like this:
> >
> > filesrc -- gdpdepay -- decodebin -- ffmpegcolorspace -- xvimagesink
> >
> > And for this case it doesn't work.
> >
> > Well, what is the result for now:
> > 1. Everything works fine if the final pipeline is hardcoded from the
> > beginning (i.e. we have gdppay right from start).
> > 2. Everything works fine without gdppay (with xvimagesink or smth. instead).
> >
> > But when I start the desired configuration I have the following:
> > 1. Xv window of the remote end appears and stalls the playing but
> > start to refresh slowly (several frames are shown rapidly in intervals
> > of 4-5 secs)
>
> Are you transferring this somehow over a network? Using gdppay and
> filesink/filesource for this is not really an optimal setup. Maybe you
> could have better luck with (de)payloaders and udp elements + jitter
> buffer.

Not really, everything is on the same machine, locally. The result I
need is to show video stream on two windows in two separate X-servers
(Xephyr servers to be exact, i.e. one window on the 1st server and
another on the 2nd one) and the second window should be pluggable
during playback. All I wanted is to stream internal GStreamer data to
second pipeline through gdppay/gdpdepay to be able to show it on
another X-server (two ximagesinks don't work because of X error). Yes,
I consider some variants with elements you mentioned but they seem to
be much more complex and I'd like to avoid them using gdp elements if
it's possible.

>
> > 2. Xv window of the main pipeline stops to play properly, too, and
> > behaves just the same way like the remote one.
> > 3. The main pipeline prints the following warnings to console:
> >
> > 0:00:07.134552825 19490  0x95be9c8 WARN  gdppay
> > gstgdppay.c:594:gst_gdp_pay_chain:<gdppay0> did not receive
> > new-segment before first buffer
> > 0:00:14.095700940 19490  0x948d2b0 WARN  ffmpeg
> > gstffmpegdec.c:2002:gst_ffmpegdec_video_frame:<ffdec_h2640> Dropping
> > non-keyframe (seek/init)
> > 0:00:14.691007420 19490  0x95b4978 WARN  basesink
> > gstbasesink.c:2686:gst_base_sink_is_too_late:<xvimagesink0> warning: A
> > lot of buffers are being dropped.
> > 0:00:14.691055331 19490  0x95b4978 WARN  basesink
> > gstbasesink.c:2686:gst_base_sink_is_too_late:<xvimagesink0> warning:
> > There may be a timestamping problem, or this computer is too slow.
>
> This message is pretty self-explanatory: xvimagesink is not rendering
> anything because buffers are too late. Just to try, what's the effect
> if you set sync=false on that element? What if you set the
> max-lateness property to something like e.g. a few seconds?

Thank you for suggestions, will try them. Yes, I guess it's something
with buffer timings but it seems that gdppay/gdpdepay just can't pump
data through FIFO fast enough when connected during playback. I think
so because if I set timeoverlay element after gdpdepay it shows that
time flows _very_ sporadically. What is also interesting is that if
change gdppay to "jpegenc ! avimux" connection and gdpdepay to
decodebin then everything start playing fine (just with some delay
accumulation during playback). I decided that it's gdp elements
problems and filed a bug here:

https://bugzilla.gnome.org/show_bug.cgi?id=635226

Maybe I'm mistaken but anyway, thanks for help, I'll try your
suggestions and write the results here.

>
> Regards
>
> >
> > Here's the source code of the main app:
> >
> > #include <gst/gst.h>
> > #include <glib.h>
> >
> > GstElement *_pipeline, *_fakesink, *_remotesink, *_valve, *_mpoint,
> > *_videobin, *_pipe;
> >
> > void create_pipeline_bin()
> > {
> >        GstElement *tee, *queue1, *queue2, *xvimagesink;
> >
> >        _pipeline      = gst_element_factory_make("playbin",  NULL);
> >
> >        tee                     = gst_element_factory_make("tee",  NULL);
> >        xvimagesink   = gst_element_factory_make("xvimagesink", NULL);
> >
> >        GstPad* pad;
> >
> >        _videobin = gst_bin_new("videobin");
> >        queue1                  = gst_element_factory_make("queue", NULL);
> >        queue2                  = gst_element_factory_make("queue", NULL);
> >        _valve                  = gst_element_factory_make("valve", NULL);
> >
> >        _fakesink               = gst_element_factory_make("fakesink", NULL);
> >
> >        gst_object_ref(_fakesink);
> >
> >        _mpoint = _valve;
> >
> >        gst_bin_add_many(GST_BIN(_videobin), tee, queue1, queue2, _valve,
> > xvimagesink, _fakesink, NULL);
> >
> >        gst_element_link_many(tee, queue1, xvimagesink, NULL);
> >        gst_element_link_many(tee, queue2, _valve, _fakesink, NULL);
> >        pad = gst_element_get_static_pad (tee, "sink");
> >        gst_element_add_pad (_videobin, gst_ghost_pad_new ("sink", pad));
> >        gst_object_unref (GST_OBJECT (pad));
> >
> >        g_object_set(G_OBJECT (_pipeline), "uri", "file:///home/alex/test.mkv", NULL);
> >        g_object_set(G_OBJECT (_pipeline), "video-sink", _videobin, NULL);
> >        g_object_set(G_OBJECT (_pipeline), "audio-sink", NULL, NULL);
> >
> >        gst_element_set_state (_pipeline, GST_STATE_PLAYING);
> > }
> >
> > void create_remote_bin()
> > {
> >        GstElement *gdppay;
> >        GstPad* pad;
> >
> >        gdppay          = gst_element_factory_make("gdppay",  NULL);
> >        _pipe           = gst_element_factory_make("filesink",  NULL);
> >
> >        g_object_set(G_OBJECT (_pipe), "location",
> > "/home/alex/work/playground/test.gdp", NULL);
> >
> >        _remotesink = gst_bin_new("gdpbin");
> >        gst_bin_add_many(GST_BIN(_remotesink), gdppay, _pipe, NULL);
> >        gst_element_link_many(gdppay, _pipe, NULL);
> >
> >        pad = gst_element_get_static_pad (gdppay, "sink");
> >        gst_element_add_pad (_remotesink, gst_ghost_pad_new ("sink", pad));
> >        gst_object_unref (GST_OBJECT (pad));
> > }
> >
> > void connect_remote_client()
> > {
> >        if (_remotesink && _mpoint && _videobin)
> >        {
> >                g_object_set(G_OBJECT (_valve), "drop", TRUE, NULL);
> >
> >                gst_element_unlink(_mpoint, _fakesink);
> >                gst_bin_remove(GST_BIN(_videobin), _fakesink);
> >                gst_element_set_state (_fakesink, GST_STATE_NULL);
> >
> >                gst_bin_add(GST_BIN(_videobin), _remotesink);
> >                gst_element_link(_mpoint, _remotesink);
> >
> >                gst_element_sync_state_with_parent(_remotesink);
> >
> >                gst_element_set_state (_pipeline, GST_STATE_PLAYING);
> >                g_object_set(G_OBJECT (_valve), "drop", FALSE, NULL);
> >        }
> > }
> >
> > gboolean connect_callback(gpointer)
> > {
> >        connect_remote_client();
> >        return FALSE;
> > }
> >
> > int main(int argc, char *argv[])
> > {
> >        gst_init(&argc, &argv);
> >
> >        gst_debug_set_active(true);
> >        gst_debug_set_default_threshold(GST_LEVEL_WARNING);
> >
> >        create_remote_bin();
> >        create_pipeline_bin();
> >
> >        g_timeout_add(7000, connect_callback, NULL);
> >
> >        GMainLoop *loop;
> >
> >        loop = g_main_loop_new (NULL, FALSE);
> >
> >        g_print ("Running...\n");
> >        g_main_loop_run (loop);
> >
> >        return 0;
> > }
> >
> > End on the remote end there's gst-launch command:
> >
> > gst-launch -v filesrc location=/home/alex/work/playground/test.gdp !
> > gdpdepay ! decodebin ! ffmpegcolorspace ! xvimagesink
> >
> > What is the essential problem? Is it possible to keep the "main"
> > branch (i.e. with xvimagesink in main pipeline) playing while the
> > second establishes connection via GDP protocol and then keep them
> > synced? I hoped on valve element very much and it works perfectly for
> > a couple xvimagesink but with GDP element it doesn't work, everything
> > is almost stalled.
> >
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