ffmpeg -loglevel 40

-i "udp://239.1.3.187:36563?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:43241?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:55257?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:36008?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:45589?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:58495?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:58182?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:49272?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:46846?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:35544?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:35188?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:42064?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:45835?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:34609?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:59823?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"
-i "udp://239.1.3.187:47452?fifo_size=100000000000&overrun_nonfatal=1&buffer_size=100000&analyzeduration=1000000" -deint 2 -thread_queue_size 32768 -vsync 0 -async 100 -vf "scale=480:270"

-filter_complex "[0:v][1:v][2:v][3:v]hstack=inputs=4[firstrow]; [4:v][5:v][6:v][7:v]hstack=inputs=4[secondrow]; [8:v][9:v][10:v][11:v]hstack=inputs=4[thirdrow]; [12:v][13:v][14:v][15:v]hstack=inputs=4[fourthrow]; [firstrow][secondrow][thirdrow][fourthrow]vstack=inputs=4[out]" -map "[out]"

-vcodec h264 -vsync 0 -async 1 -threads 0 -profile:v main -level 4 -preset medium -tune grain -b:v 10000k -bufsize 4000k -minrate 8000k -maxrate 12000k -an -flush_packets 0 -keyint_min 25 -g 25 -metadata service_provider=Nextologies -metadata service_name=MultiScreenTest -f mpegts -mpegts_flags +resend_headers+pat_pmt_at_frames -pcr_period 10 -y "udp://239.1.3.187:1234?pkt_size=1316&reuse=1&buffer_size=1000000&fifo_size=100000000&burst_bits=2500000"