[FFmpeg-user] minterpolate only frames 3, 8, 13, 18, etc.

Mark Filipak markfilipak.windows+ffmpeg at gmail.com
Sun Apr 5 18:11:21 EEST 2020

Example:                  filter?  option?      value?  option? value?
                           v        v            v       v      v
ffmpeg -i input -filter:a loudnorm=print_format=summary:linear=true  output
                         ^                              ^
                         What is this?                  Colon or semicolon?
                                                        Ted said semicolon.

Hmmm... "Ted said semicolon". That's almost a koan.

How about this BNF?
ffmpeg -i IN [-filter [filterchain]] OUT
filterchain = filtername[=option[=value]][:option[=value] ...][,filterchain ...]
                                                                correct delimiter?

What is this:
[in_link_1]...[in_link_N]filter_name at id=arguments[out_link_1]...[out_link_M]
trying to say? It's not normative BNF. I don't know what it means.


"filter_name is the name of the filter class of which the described filter is an instance of, and 
has to be the name of one of the filter classes registered in the program optionally followed by 
"@id". The name of the filter class is optionally followed by a string "=arguments"."

Wait a minute. Is filter_name optionally followed by "@id" or by "=arguments"? What if there's both? 
Can "@id" & "=arguments" be in any order? Somehow, I don't think so -- it's an instance that's not 
covered in the doc. And what is "id"? ...Perhaps I'll run into it again further down in the text.


"It may have one of two forms:" followed by *3* bullets? :)


That's enough for one post. I'm sleepy. The important thing is the BNF. As you concatenate the 
filter chain, do you use comma as the delimiter?

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