FFMPEG frame-rate conversion (59.94 -> 25) linear 4k HEVC stream to ingest into Wowza Streaming Engine

Hi,

We have other channels where we perform the same task and use the same FFMPEG command, those channels are H264 and up to HD (1080p30). This is the first time we need to do it with HEVC and 4K.
The particular stream is a CBR 16Mbps and we need to create a 25fps version of it using FFMPEG. We use our on-prem servers to do that before sending it to Wowza for multi-distribution.
Here is the FFMPEG command we are using:

ffmpeg -re -i ‘udp://127.0.0.1:8011?fifo_size=5860000&overrun_nonfatal=1’ -c:v libx265 -x265-params ‘profile=main10:crf=30:keyint=25:weightp=0:no-scenecut:fixed_gop=1’ -r 25 -b:v 14M -minrate 14M -maxrate 14M -preset medium -bufsize 14M -tune zerolatency -streamid 0:100 -streamid 1:1100 -mpegts_pmt_start_pid 0x0020 -mpegts_service_id 100 -c:a aac -b:a 128k -ar 48000 -metadata service_provider=“Intelsat” -metadata service_name=“NAME_4K_25fps” -muxrate 16M -f mpegts ‘udp://127.0.0.11:9011?pkt_size=1316’

It works well for about 2 minutes and then we get the “Circular Buffer Overrun” creating multiple errors and crashing at the end.

I am wondering if someone has done this before with 4k and HEVC and what other tweaks on the FFMPEG command are needed.

Thanks!