<div dir="ltr"><div><div><div>Hi,<br><br></div>The seek works when the format is TIME, e.g.:<br><br><div style="margin-left:40px">pipeline.seek_simple(Gst.Format.TIME, Gst.SeekFlags.FLUSH, 0.3*Gst.SECOND)<br><br></div>but not when the format is BUFFERS, e.g.:<br><br><div style="margin-left:40px">pipeline.seek_simple(Gst.Format.BUFFERS, Gst.SeekFlags.FLUSH, 1000)<br><br></div>Does this make any sense?<br><br></div>Thanks,<br></div>Hjalmar<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Dec 7, 2015 at 4:07 PM, Hjalmar Turesson <span dir="ltr"><<a href="mailto:hturesson@gmail.com" target="_blank">hturesson@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div>Perfect example. It does exactly what I wanted.<br><br>But... The seek returns false (the other part works perfectly)<br><br><div style="margin-left:40px"> CLI='filesrc location=%s ! decodebin ! appsink name=sink' % filename<br> pipeline=Gst.parse_launch(CLI)<br> # get sink<br> appsink=pipeline.get_by_name("sink")<br> # set to PAUSED to make the first frame arrive in the sink<br> pipeline.set_state(Gst.State.PAUSED)<br><b> pipeline.seek_simple(Gst.Format.BUFFERS, Gst.SeekFlags.FLUSH, frame_number)</b><br> smp = appsink.emit('pull-preroll')<br> buf = smp.get_buffer()<br><br> data=buf.extract_dup(0, buf.get_size())[:307200] # Only 1/2 of expected RGB size<br> frame = np.fromstring(data,dtype='uint8').reshape((480,640,1))<br><br><br></div>Thanks a lot,<br><br></div>Hjalmar<br></div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Dec 7, 2015 at 1:47 PM, Tim Müller <span dir="ltr"><<a href="mailto:tim@centricular.com" target="_blank">tim@centricular.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Mon, 2015-12-07 at 13:30 -0300, Hjalmar Turesson wrote:<br> <br> Hi Hjalmar,<br> <br> This (C) example shows how to retrieve frames from appsink, perhaps you<br> find it useful:<br> <br> <a href="http://cgit.freedesktop.org/gstreamer/gst-plugins-base/tree/tests/examples/snapshot/snapshot.c" rel="noreferrer" target="_blank">http://cgit.freedesktop.org/gstreamer/gst-plugins-base/tree/tests/examp<br> les/snapshot/snapshot.c</a><br> <br> It uses the pull-preroll signal/API, that only works once, if you want<br> to retrieve one frame, and then another one, then just use the pull-<br> sample API N times.<br> <br> There are two ways to use appsink: one is to have it emit a signal<br> (new-sample) whenever a buffer arrives, and then you pull it in the<br> callback). The other is to simply set the pipeline to PLAYING and then<br> do pull-sample, which will block and wait for a simple if none is<br> available yet then.<br> <br> Note that from the "new-sample" signal callback you can also return<br> GST_FLOW_EOS if you don't want to be called again.<br> <br> Cheers<br> -Tim<br> <div><div><br> > Hi,<br> ><br> > I would like read individual frames to python/numpy for analysis.<br> > That is, I want call a function that reads and returns 1 frame. I<br> > thought I could do this with appsink, but I have 2 problems. 1) I<br> > cannot return a frame from the callback function 2) It doesn't just<br> > read 1 frame.<br> ><br> > Simple example that does not do what I want:<br> ><br> > import gi<br> > gi.require_version('Gst', '1.0')<br> > from gi.repository import GObject, Gst, Gtk<br> > GObject.threads_init()<br> > Gst.init(None)<br> > ##########<br> ><br> > CLI='filesrc location=testVideo.mp4 ! decodebin ! appsink<br> > name=sink'<br> > pipeline=Gst.parse_launch(CLI)<br> > appsink=pipeline.get_by_name("sink")<br> > appsink.set_property("max-buffers",1)<br> > appsink.set_property('emit-signals',True)<br> > appsink.set_property('sync',False)<br> > <br> > def on_new_buffer(appsink):<br> > sample = appsink.emit('pull-sample')<br> > #get the buffer<br> > buf=sample.get_buffer()<br> > data=buf.extract_dup(0,buf.get_size())<br> > return False # Here I would like to return the frame<br> ><br> > appsink.connect('new-sample', on_new_buffer)<br> > pipeline.set_state(Gst.State.PLAYING)<br> > pipeline.set_state(Gst.State.NULL)<br> ><br> > Is it possible to do what I want to do using appsink?<br> ><br> > Another strategy I tried is to use fdsink and read the data from that<br> > location:<br> ><br> > import os<br> ><br> > readfd, writefd = os.pipe()<br> > frame_size_bytes = 460800<br> ><br> > CLI='filesrc location=testVideo.mp4 ! decodebin ! fdsink<br> > name=sink' <br> > pipeline=Gst.parse_launch(CLI)<br> > fdsink=pipeline.get_by_name("sink")<br> > fdsink.set_property("fd", readfd)<br> ><br> > pipeline.set_state(Gst.State.PLAYING)<br> > data = os.read(readfd, frame_size_bytes)<br> > pipeline.set_state(Gst.State.PAUSED)<br> ><br> > This does not work either. The code hang at the data = os.read...<br> > line, maybe trying to play the entire file before moving on.<br> ><br> > How can I read only one frame?<br> ><br> > Thanks,<br> > Hjalmar<br> </div></div>> _______________________________________________<br> > gstreamer-devel mailing list<br> > <a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank">gstreamer-devel@lists.freedesktop.org</a><br> > <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a><br> <span><font color="#888888">--<br> Tim Müller, Centricular Ltd - <a href="http://www.centricular.com" rel="noreferrer" target="_blank">http://www.centricular.com</a><br> <br> <br> _______________________________________________<br> gstreamer-devel mailing list<br> <a href="mailto:gstreamer-devel@lists.freedesktop.org" target="_blank">gstreamer-devel@lists.freedesktop.org</a><br> <a href="http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel" rel="noreferrer" target="_blank">http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel</a><br> </font></span></blockquote></div><br></div> </div></div></blockquote></div><br></div>