Textoverlay questions

[William Salibrici]

I am using the following simple pipeline segment to add a text area under my compositor video output. In a separate thread, I set the "text" property once every second to update the rendered text. For my application, the text updates must be real-time.



videotestsrc pattern=white ! textoverlay ! queue ! comp.sink_2


My development machine is windows 7 and I'm using GStreamer 1.10.4 with your windows pre-built binaries.
My overall pipeline runs without errors but the text updates are not always 1 second apart. Sometimes there are pauses between updates greater than 1 second. Other times updates come back to back with no discernable delay. Sometimes updates appear to be skipped altogether [maybe they are just flying by too fast for me to see them]. The latency for displaying text seems to vary quite a bit.
So, here are some questions:

  1.  What is the latency for displaying text [the time between when the g_object_set function is called to set the text to be displayed and when the text will actually be displayed]?
  2.  Is there any way to achieve a relatively constant latency for displaying text?
  3.  Is there any way force the text to be synchronized with the other input video streams to my compositor?



Perhaps I am missing something. Can anyone answer these questions?
Thanks so much for your help,
Bill Salibrici
Lattice Incorporated

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