Overlay on a live source

[Paul Barber]

Hi,
I have a similar problem but have not really solved it either. Can you use a videorate element to maintain a constant fast frame rate (by duplicating frames) from a source that may stall or run at a reduced rate for some reason?
Cheers,
Paul

On 17 October 2014 22:20:02 BST, "Moore, Thomas (FtWorth)" <Thomas.Moore2 at ATK.COM> wrote:
>Hello,
>
>I have an interesting problem that I hope you can help me with. I'm
>working on an application that will overlay custom graphics onto a live
>video stream in real time. Ultimately, I'm planning on using a udpsrc
>and the appropriate decoders to process the video stream and
>cairooverlay to generate the custom graphics (we already have the cairo
>part done from a previous project, so that part is easy). I've been
>experimenting with several different combinations of plugins to achieve
>the desired effect, but I'm running into two problems.
>
>First, the pipeline isn't constructed until the udpsrc receives data. I
>think this can be overcome by using a videotestsrc in place of the
>udpsrc (and decoders) and a videoswitch to swap to the video stream
>once data is detected via a filter pad.
>
>Second, if the video stream stops (or pauses), then so does the output
>of the pipeline. At first, I just had the cairooverlay on top of the
>uspsrc/decoder chain, and it makes sense that the pipeline will stop if
>the streaming video stops. My next thought was to use a video mixer to
>mix the cairooverlay atop a transparent videotestsrc with the live
>video stream. This approach sort of works, but with a live stream as an
>input to the video mixer, the pipeline still seems to stop if the video
>stream stops. Here is an example pipeline that demonstrates the issue:
>
>gst-launch-1.0 -v videotestsrc name=tstsrc0 is-live=true ! \
>                  video/x-raw,width=1280,height=720,framerate=1/1 ! \
>                  videomixer name=mix ! \
>                  videoconvert ! \
>                  ximagesink sync=false \
>          videotestsrc name=tstsrc1 pattern=ball background-color=0 ! \
>       video/x-raw,format=ARGB,width=1280,height=720,framerate=10/1 ! \
>                  mix.
>
>You'll notice that tstsrc0, which is the underlay, is running at 1 fps
>and tstsrc1, the overlay, is running at 10 fps. If is-live is set to
>false on tstsrc0, then the pipeline runs as expected with the ball
>moving at 10 fps and the underlay updating at 1 fps. However, when
>is-live is set to true (which requires the sync=false on the sink to
>prevent timing errors), the ball moves for about half a second and then
>stops for about half a second and then repeats.
>
>For these tests, I originally started with GStreamer 0.10 as installed
>with openSUSE 12.1, but I have since updated to openSUSE 13.1 and am
>running the following versions:
>
>gstreamer 1.4.3-3.2
>gstreamer-plugins-base 1.4.3-2.4
>gstreamer-plugins-good 1.4.3-2.1
>gstreamer-plugins-bad 1.4.3-5.7
>gstreamer-plugins-bad-orig-addon 1.4.3-5.7
>gstreamer-plugins-ugly 1.4.3-2.2
>gstreamer-plugins-ugly-orig-addon 1.4.3-2.2
>gstreamer-plugins-libav 1.4.3-1.1
>
>Any ideas as to how I can get this working would be greatly
>appreciated.
>
>Thanks!
>
>Thomas
>
>
>
>
>
>
>
>
>------------------------------------------------------------------------
>
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