Dynamic text-overlay on live-stream using gst-launch-1.0

Wed Mar 1 01:51:05 UTC 2017

Thank you Philippe,

I’ve tried it and now I’m getting a new message:

tail -f /home/pi/test.txt | /opt/gst/bin/gst-launch-1.0 fdsrc fd=0 ! "text/x-raw, format=utf8" ! txt. videotestsrc ! videoconvert ! decodebin ! textoverlay name=txt ! omxh264enc target-bitrate=800000 control-rate=3 ! tcpserversink host=0.0.0.0 port=9000

Setting pipeline to PAUSED ...

Pipeline is PREROLLING ...

WARNING: from element /GstPipeline:pipeline0/GstTextOverlay:txt: Could not multiplex stream.

Additional debug info:

gstbasetextoverlay.c(2340): gst_base_text_overlay_text_event (): /GstPipeline:pipeline0/GstTextOverlay:txt:

received non-TIME newsegment event on text input

Pipeline is PREROLLED ...

Setting pipeline to PLAYING ...

New clock: GstSystemClock

Any idea what that means?

Thanks!

From: gstreamer-devel [mailto:gstreamer-devel-bounces at lists.freedesktop.org] On Behalf Of philippe renon
Sent: Monday, February 27, 2017 8:03 AM
To: Discussion of the development of and with GStreamer <gstreamer-devel at lists.freedesktop.org>
Subject: Re: Dynamic text-overlay on live-stream using gst-launch-1.0

textoverlay accepts caps defined as: 
text/x-raw, format=(string){ pango-markup, utf8 }

may be you need to set caps to "text/x-raw, format=utf8" or something along those line.

Le Lundi 27 février 2017 16h34, Nicolas Dufresne <nicolas at ndufresne.ca <mailto:nicolas at ndufresne.ca> > a écrit :

Le lundi 27 février 2017 à 07:05 -0800, Adam Plocher a écrit :

Nicolas, thank you for your response.  fdsrc seems like it would be a good solution, but I'm having issues getting it to work.

It seems like I need to specify the caps after the fdsrc, otherwise it fails in other ways.  e.g.

Specifying text/x-raw:

tail -f /home/pi/test.txt | /opt/gst/bin/gst-launch-1.0 fdsrc fd=0 ! "text/x-raw" ! txt. videotestsrc ! videoconvert ! decodebin ! textoverlay name=txt ! omxh264enc target-bitrate=800000 control-rate=3 ! tcpserversink host=0.0.0.0 port=9000

I think you forgot to keep subparse element.

Results in:

Pipeline is PREROLLING ...

ERROR: from element /GstPipeline:pipeline0/GstCapsFilter:capsfilter0: Filter caps do not completely specify the output format

Additional debug info:

gstcapsfilter.c(455): gst_capsfilter_prepare_buf (): /GstPipeline:pipeline0/GstCapsFilter:capsfilter0:

Output caps are unfixed: text/x-raw, format=(string){ pango-markup, utf8 }

ERROR: pipeline doesn't want to preroll.

Specifying text/plain:

tail -f /home/pi/test.txt | /opt/gst/bin/gst-launch-1.0 fdsrc fd=0 ! "text/plain" ! txt. videotestsrc ! videoconvert ! decodebin ! textoverlay name=txt ! omxh264enc target-bitrate=800000 control-rate=3 ! tcpserversink host=0.0.0.0 port=9000

Results in:

0:00:00.501757360  4549  0x1e085c0 ERROR           GST_PIPELINE grammar.y:714:gst_parse_perform_link: could not link fdsrc0 to txt, txt can't handle caps text/plain

WARNING: erroneous pipeline: could not link fdsrc0 to txt, txt can't handle caps text/plain

No caps at all:

tail -f /home/pi/test.txt | /opt/gst/bin/gst-launch-1.0 fdsrc fd=0 ! txt. videotestsrc ! videoconvert ! decodebin ! textoverlay name=txt !  omxh264enc target-bitrate=800000 control-rate=3 ! tcpserversink host=0.0.0.0 port=9000

Results in:

Pipeline is PREROLLING ...

WARNING: from element /GstPipeline:pipeline0/GstTextOverlay:txt: Could not multiplex stream.

Additional debug info:

gstbasetextoverlay.c(2449): gst_base_text_overlay_video_event (): /GstPipeline:pipeline0/GstTextOverlay:txt:

received non-TIME newsegment event on video input

WARNING: from element /GstPipeline:pipeline0/GstDecodeBin:decodebin0: Delayed linking failed.

Additional debug info:

./grammar.y(510): gst_parse_no_more_pads (): /GstPipeline:pipeline0/GstDecodeBin:decodebin0:

failed delayed linking some pad of GstDecodeBin named decodebin0 to some pad of GstTextOverlay named txt

ERROR: from element /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0: Internal data stream error.

Additional debug info:

gstbasesrc.c(2951): gst_base_src_loop (): /GstPipeline:pipeline0/GstVideoTestSrc:videotestsrc0:

streaming stopped, reason not-linked (-1)

ERROR: pipeline doesn't want to preroll.

There is some information here (regarding the older version of gst-launch): 

http://gstreamer-devel.966125.n4.nabble.com/Dynamic-text-again-td3676141.html

And that links to this bug that was resolved (again, old gst-launch): 

https://bugzilla.gnome.org/show_bug.cgi?id=654959

I've seen a couple examples which used the "text/plain" caps.

I'm certainly open to cracking open the Python lib and giving it a shot.  I would need to read up on it a bit and I'm not familiar with the appsrc, either, but that's something else I'm open to. I have done very basic stuff with the Python libs but nothing too fancy or dynamic (basic pipelines, no more complex than I would get from gst-launch-1.0).

What would you recommend?  Is there an example or resource you could point me towards?

Thank you for your help

On Sun, Feb 26, 2017 at 2:46 PM, Nicolas Dufresne <nicolas at ndufresne.ca <mailto:nicolas at ndufresne.ca> > wrote:

Le dimanche 26 février 2017 à 06:18 -0800, Adam Plocher a écrit :
> Hello, I apologize if I'm posting this in the wrong place. I've
> previously asked this on stackoverflow and never got a response: http
> ://stackoverflow.com/ questions/42128804/polling-a- text-file-and- <http://stackoverflow.com/questions/42128804/polling-a-text-file-and-> 
> overlaying-the-result-in- gstreamer
>
> I have a Raspberry Pi with a camera and I'm live streaming that back
> to another unit (it's for a baby monitor).  On the same Pi, I have a
> temperature sensor that is dumping the current temp to a file every 5
> seconds.
>
> My question: Is it possible to somehow poll that txt file and update
> a text-overlay on the live stream based on the current contents of
> that file?

filsesrc does not have this feature unfortunatly. I believe using
fdsrc, you could:

  tail -f text.txt | gst-launch-1.0 fdsrc ! ...

Let me know if that is a good work-around. If you are writing an app,
this can be done with a pipe, or if you prefer, with appsrc.

>
> I've tried using a filesrc and subparse, and it will grab it
> initially if I format the input text file properly, but it doesn't
> seem to update itself:
>
> gst-launch-1.0 -v \
>     filesrc location=/home/pi/temp.txt ! subparse ! txt. rpicamsrc
> awb-mode=0 awb-gain-red=1 awb-gain-blue=2 rotation=0 bitrate=820000
> preview=false brightness=67 contrast=30 sharpness=40 \
>     ! video/x-h264,width=800,height= 480,framerate=10/1 \
>     ! h264parse ! decodebin ! videoconvert ! clockoverlay shaded-
> background=true draw-shadow=true font-desc="Nimbus Mono" \
>     ! textoverlay name=txt shaded-background=yes \
>     ! omxh264enc control-rate=3 target-bitrate=850000 \
>     ! tcpserversink host=0.0.0.0 port=5555 sync=true
>
> The input file looks like this:
> 1
> 00:00:00,000 --> 99:59:59,000
> 69 degrees
> Thank you!
> ______________________________ _________________
> gstreamer-devel mailing list
> gstreamer-devel at lists. freedesktop.org <mailto:gstreamer-devel at lists.freedesktop.org> 
> https://lists.freedesktop.org/ mailman/listinfo/gstreamer- devel <https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel> 
______________________________ _________________
gstreamer-devel mailing list
gstreamer-devel at lists. freedesktop.org <mailto:gstreamer-devel at lists.freedesktop.org> 
https://lists.freedesktop.org/ mailman/listinfo/gstreamer- devel <https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel> 

_______________________________________________
gstreamer-devel mailing list
gstreamer-devel at lists.freedesktop.org <mailto:gstreamer-devel at lists.freedesktop.org> 
https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

_______________________________________________
gstreamer-devel mailing list
gstreamer-devel at lists.freedesktop.org <mailto:gstreamer-devel at lists.freedesktop.org> 
https://lists.freedesktop.org/mailman/listinfo/gstreamer-devel

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/gstreamer-devel/attachments/20170228/4a46086d/attachment-0001.html>