ffmpeg -f flv -i rtmp://// -f flv -i rtmp://// \
-filter_complex "[1:v]scale=w=96:h=72[ckout];[0:v][ckout]overlay=x=W-w-10:y=H-h-10[out]" -map "[out]" \
-c:v libx264 -profile:v high -preset medium \
-filter_complex amix -c:a aac \
-f flv -y
rtmp:////merge
&&
echo "ok"