[FFmpeg-user] What is a "pad" in the context of an "input pad", an "output pad" and a "filter pad"

[Clay]

Thanks for the perspective, Phil :-)  As I am not an ffmpeg expert, when
I [attempt to] mentally digest the documentation, I drill down into the
minutia until I hit "descriptively fundamental particles" ...often,
where I expect to find fundamental descriptions, there is just a hole
(in the meaning)..so I drop a rock, as a sounding method (oh crap, more
audio terminology) and listen for the splash.  In the [filtergraph]
context of Pad, that splash never came :-D

So..  It seems like its more of a temporary gateway/portal for
specifically crunched data.
>> In the case of ffmpeg _filters_, it looks like #3 is closest as a point of> interconnection but #2 could apply to 'pad' and 'apad' although IMHO 'fill'> would be a better term.
> I would tend to agree that what's going on here is that the English word "pad" has a very large number of meanings and ffmpeg appears to be mixing those meanings in a way that might reasonably be expected to cause confusion.
> At least part of this is happening because ffmpeg, by its nature, crosses disciplines between IT and media production. Because of changes in the media industry over the life of the ffmpeg project, this has become more and more true over time, as digital post production has become ubiquitous. It's sort of inevitable this would happen and it probably isn't anyone's fault. Dafter things have happened to Premiere.
> It's also not the first time that this sort of collision has occurred (witness the state of colour management in ffmpeg until fairly recently, and I'll never forget the time someone fairly senior started complaining that drop-frame timecode was untidy, to a reaction from more experienced hands that ranged from mirth to disbelief).
> It seems that a cleanup of terminology is in order and at least something's going to have to give.
> P