Non-mavlink ( gstreamer UDP ) video quality for android application

Let me share with you short sample move that shows Qground Control FPV experience vs AirPI control for Android.
This movie is split into 2 parts . The first one capture FPV experience with AirPI control software installed on my Galaxy Tab A and second one shows Qground Control in action.
For recording purposes software was changed during the flight to show the same gstreamer pipeline decoded by both applications in one time. Common weather condition, common LTE link etc… Additionally I did use low-res video ( LTE optimized ) to get the best FVP experience that I can receive right now with my configuration. Copter use regular Raspberry PI + Pixhawk setup, gstreamer pipeline is send via UDP and LTE to ground station tablet with public IP.
As you can see quality of decoded video by AirPI control is much more better then Qground Control. Frankly speaking I would like to continue in future with Qground Control only but as for now it`s not possible due quality of decoded video.
Could you let me know how to increase quality od decoded video to get similar experience to AirPI control? What can be root cause for this pixelization shown in Qground Control part. Maybe reason can be related to decoder build in your app ?
One more at the end of this post. I did test also Towel Android application and quality is the same as Qground Control. It looks like both developers use a same solution that seems to be not so effective as AirPI control.
click link to open movie >>>