<div dir="ltr"><div>Here's my gstreamer version:<br></div><div><br></div><div>gst-launch-1.0 --version<br></div><div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">gst-launch-1.0 version 1.12.4</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">GStreamer 1.12.4</div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><a href="https://packages.gentoo.org/package/media-libs/gstreamer">https://packages.gentoo.org/package/media-libs/gstreamer</a></div><br></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline">I have two examples of queue working contrary to expectations</span><br></div><div><span style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;background-color:rgb(255,255,255);text-decoration-style:initial;text-decoration-color:initial;float:none;display:inline"><br></span></div><div>gst-launch-1.0 -v -e \</div><div>    videotestsrc ! tee name=t0 \</div><div>    t0. ! queue ! x264enc ! matroskamux ! filesink location="test.mkv" \</div><div>    t0. ! queue ! queue ! autovideosink</div><div><br></div><div>Works, with both the file, and the on-screen display working</div><div><br></div><div>gst-launch-1.0 -v -e \</div><div>    videotestsrc ! tee name=t0 \</div><div>    t0. ! queue ! x264enc ! matroskamux ! filesink location="test.mkv" \</div><div>    t0. ! queue ! autovideosink</div><div><br></div><div>Does not work. The autovideosink shows a single frame, and the mkv file is zero bytes. What makes the second queue needed on the last line?</div><div><br></div><div>Here's another set of examples.</div><div><br></div><div>gst-launch-1.0 -v -e \</div><div>    videotestsrc ! tee name=t0 \</div><div>    t0. ! queue ! autovideosink \</div><div>    t0. ! queue ! autovideosink</div><div><br></div><div>Works.</div><div><br></div><div>gst-launch-1.0 -v -e \</div><div>    videotestsrc ! tee name=t0 \</div><div>    t0. ! queue ! autovideosink \</div><div>    t0. ! autovideosink</div><div><br></div><div>Doesn't. Why not? Why do both outputs from the tee need to be queues? At worst, I'd expect one autovideosink to work and the other to be blank, but instead one displays a single frame and the other is black.</div><div><br></div><div>But the following DOES work. What's going on?</div><div><br></div><div>gst-launch-1.0 -v -e \</div><div>    videotestsrc ! tee name=t0 \</div><div>    t0. ! queue ! autovideosink \</div><div>    t0. ! queue ! autovideosink \</div><div>    t0. ! autovideosink</div><div><br></div><div>Why does adding a third output negate the need for a queue on all of them?</div><div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial"><br></div><div style="color:rgb(34,34,34);font-family:arial,sans-serif;font-size:small;font-style:normal;font-variant-ligatures:normal;font-variant-caps:normal;font-weight:400;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;text-decoration-style:initial;text-decoration-color:initial">Does anyone know why queue behaves like this?</div></div><div><br></div></div>