Re: [Mlt-devel] How to get a true constant video bitrate (not only muxrate) in an UDP output with Melt

[Brian M. <co...@br...>]

>
> I need to get a true constant video bitrate in an UDP output address.
>
> By using cbrts consumer I am getting a constant muxrate in the UDP 
> output, but not a constant video bitrate.
> I have noticed that varying the gop size has an effect in the shape of 
> the output video bitrate curve but still I am not getting a flat (or 
> almost flat) video bitrate line in the output analyzer.
>
> This is the script I am using:
>
> melt -profile atsc_1080i_50 test_1.mp4 \
> -consumer cbrts udp.address=10.192.33.14 udp.port=5678 udp.ttl=12 
> udp.reuse=1 udp.rtp=0 muxrate=6000000 udp.buffer=1000 \
> vcodec=libx264 bufsize=5505024 vb=3M minrate=3M maxrate=3M g=15 bf=2 \
> acodec=mp2 ab=160k threads=3 real_time=1
>
> I am trying to add this libx264 encoding option
>
> -x264-params "nal-hrd=cbr:force-cfr=1"
>
> as described in this post:
>
> http://slhck.info/video/2017/03/01/rate-control.html
>
> but It seems that Melt is ignoring it although It is not showing any 
> error.
>
> Any help would be really appreciated!
>
> Regards,
>
> David

"-x264-params" is the "new" ffmpeg option. MLT still uses the old 
option: "x264opts"
  https://mltframework.org/plugins/ConsumerAvformat/#x264opts

I suppose we will have to update to use the new option some day. In the 
mean time, try using "x264opts".

~Brian