Poor quality of stream with omxh264enc / snowmix

[Oliver Jaksch]

Hi list,

I'm playing with snowmix. Great stuff which gives a lot of fun creating video 
feeds!
I created a simple ini-file with two video feeds, some pics'n'stuff w/o audio 
for snowmix and tried to stream it via tcp (av_output2tcp_server). As this was 
easy with a regular PC, it was somewhat difficult with a RPI2 as x264enc hit 
the brakes there.
After some reading I got it to work using omxh264enc instead. Works flawless 
and stable so far, but output quality is ugly - like a low quality mpg1 video 
from the old days in hi-res. Said this...parts of the output are crisp and 
clear, but grey gradient background is full of artefacts and running text 
flickers.
Gained some qualtity by changing profile from main to high, but quality is 
still far from perfect, as I achieved this with PC. Fiddled with some of the 
omx specific parameters but nothing seems to improve the quality.

Bug or missed I something? Maybe the omx parts are WIP and I'm too impatient.

Thanks in advance to anybody who may help.
-
Oliver


VIDEO_SRC='shmsrc socket-path='$ctrsocket' do-timestamp=true is-live=true'
VIDEOFORMAT=$VIDEOBGRA', width=(int)'$system_width', 
height=(int)'$system_height', framerate=(fraction)'$ratefraction
VIDEOCONVERT=videoconvert
VIDEOFORMATOUT='video/x-h264, alignment=au, stream-format=byte-stream, 
profile=high'

gst-launch-1.0
 $VIDEO_SRC
 $VIDEOFORMAT          !\
 queue                 !\
 $VIDEOCONVERT         ! \
 omxh264enc inline-header=true periodicty-idr=1  !\
 $VIDEOFORMATOUT,control-rate=variable,target-bitrate=5000000,quant-i-
frames=250       !\
 h264parse             !\
 queue                 !\
 matroskamux name=muxer streamable=true !\
 queue                 !\
 tcpserversink host=0.0.0.0 port=$SERVER_PORT sync-method=2 recover-
policy=keyframe