How to use text overlay in GStreamer?

[toanjunifer]

Hi,

I'm using gstreamer to stream video with text overlay. I get this error:

(gst-launch-1.0:2763): GStreamer-CRITICAL **: gst_buffer_get_memory_range: assertion '(len == 0 && idx == 0 && length == -1) || (length == -1 && idx < len) || (length > 0 && length + idx <= len)' failed

With commandline:

gst-launch-1.0 v4l2src device=/dev/video1 num-buffers=300 ! videoconvert ! 'video/x-raw,width=1280,height=720,framerate=(fraction)30/1' ! textoverlay text="Hi There" valignment=top halignment=left font-desc="Sans, 12" ! queue ! x264 ! mp4mux ! filesink location=video.mp4

I don't know why does it happen. What should I do now ?

Thank you so much,

Toan

[toanjunifer · Accepted solution]

I found that it's just is a warning. But it's actually impact to video quality if I run it directly. If I run it with schedule, it's will be fine. So I decide to close this question. Thank you joanxie‌ for your help. 

[joanxie]

what board and bsp version do you use?

[toanjunifer]

I'm using iMX6S Varisite board. BSP is 4.1.15