Python Appsrc Internal data stream error

Yaro Kifor yarokifor at
Fri Aug 21 19:39:57 UTC 2020

My caps weren't set right. I set GST_DEBUG=6 and saw this:

GST_CAPS gstpad.c:5624:pre_eventfunc_check:<videoconvert0:sink> caps video/x-raw, format=(string)GRAY8, width=(int)80, height=(int)60, framerate=(string)8.6/1 not accepted
GST_PADS gstpad.c:5879:gst_pad_send_event_unchecked:<videoconvert0:sink> pre event check failed

`FlirLeptonCameraSrc (my implementation of appsrc) `created the caps from Gst.Caps.new_empty_simple and everything was set with set_value. I think the framerate wasn't set correctly. The framerate property doesn't seem to work with strings. I got it to work with `Gst.Caps.from_string instead.` I also had to change the framerate to "0/1". The framerate property also doesn't work with decimals in numerator.

My buffer pts and duration also have issues, but doesn't relate to this issue.

Thank you for your time if you read this and I hope someone finds this helpful,
Yaro Kifor

On Fri, Aug 21, 2020, at 11:06, Yaro Kifor wrote:
> Hello,
> I am working on a gstreamer project in python. I am using appsrc to push buffers to my pipeline. When I run my application my gtksink appears but a black void is displayed. I checked to make sure appsrc is pushing buffers, but when it does the debugging logs show "error: Internal data stream error" and "error: streaming stopped, reason not-negotiated (-4)". I looked into this and saw it could be something with my appsrc's caps, but I am very sure they are correct. However I still could be setting them incorrectly.
> I am using Python 3.8.2 on Pop!_OS 20.04 LTS (Basically Ubuntu 20.04). I've tried pushing buffers filled with random data and still no luck.
> My python script:
> Logs:
> Please let me know if there's any more information I could provide. Also note I haven't implement exiting the application properly just yet.
> Any help or guidance would be greatly appreciated. I am sorry if this mailing list isn't the correct place to ask for help. If there's a better place please let me know!
> Thank you for reading this,
> Yaro Kifor
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