[FFmpeg-user] How to dynamically drop frames as required to keep transcoding real time?

[Mark Filipak (ffmpeg)]

On 2021-04-07 21:51, Adrian Cable wrote:
> Mark,
> 
>> Sorry, I thought XXX referred to the output -- -vf fps=fps=XXX is *output* frame rate. To the best
>> of my knowledge, the input frame rate of VFR video can't be specified.
> 
> I’m referring to XXX as the maximum *output* frame rate that the pipeline can support at a given time, while keeping up with the input.

I think what you want is an encoder with a quality throttle that can be used to dial down the 
quality (and hence, reduce encoding time) when it can't keep up with the input at the current 
compression factor. I'm pretty sure that such an encoder control exists because what you want to do 
is not at all uncommon. That is, if I understand what you want to do.

I don't know how to do it because I don't stream, but I've seen the issue addressed here previously. 
Perhaps someone more knowledgeable will read this and help.