On 03/09/2020 06:41 PM, Michael Koch wrote:
Am 09.03.2020 um 23:31 schrieb Mark Filipak:
On 03/09/2020 05:30 PM, Michael Koch wrote:
Am 09.03.2020 um 21:49 schrieb Mark Filipak:
On 03/09/2020 03:39 PM, [email protected] wrote:
Well, I'm a dumb user and google gave me LOTS and LOTS of
commandlines that work - simply filter the google results by the
"date in the last year" to be sure you get the latest syntax. Lots.
You appear to continually avoid "what is it you wish to do with a
specific example video that you have" type questions...
That's a fair observation. You deserve a serious response. May I
provide perspective?
It appears to me that ffmpeg commands have the following structure:
ffmpeg A [[B ...] -i C [D ...]...] [[E ...] [F ...]...]
[[i ]...] : inputs
A : general options
[B ...] : input-specific pre-options
C : input URL
[D ...] : input-specific post-options
...[[]...] : outputs
[E ...] : output-specific filters
[F ...] : output URL
Full disclosure: I don't know if all of the above is correct.
As far as I know, there are no input-specific post-options.
Thank you, Michael. I'll keep that in mind.
All input specific options must be written before the input. Remove D.
General options can also be written before the output (between E and F).
Thank you! That's really good to know.
Filters are always output specific. So E ist just the filter chain.
True. I intended to indicate that E is an individual filter. I'm
unsure whether, in a filter chain, all filters are delimited by
semi-colons.
commas or semi-colons, it's described in chapter 30:
https://www.ffmpeg.org/ffmpeg-all.html#Filtering-Introduction
Thanks again. I of course had read that -- I've read everything -- but
it was unclear regarding the structure. You have clarified it.
At this point, I could write a more specific template that includes some
of the internals of a filter chain, but then I'd have to include
brackets that delimit filter taps (e.g., '[0:1]'), but those brackets
would conflict with the token brackets that indicate optional inclusion
(e.g., '[B ...]'), so I don't want to include filter delimiters at the
top level. So, I'm submitting this:
ffmpeg [A ...] [B ...] -i C [[D ...] -i E ...] [F ...] [G] [H ...] [[I
...] J [[K ...] L ...]]
A ... : general options, if any
B ... : first input options, if any
-i C : first input-URL
D ... : second input options, if any
-i E : second input-URL, if any, etc.
F ... : more general options, if any
G : filter chains, if any
H ... : more general options, if any
I ... : first output-specific filters, if any
J ; first output-URL, if any
K ... ; second output options, if any
L : second output-URL, if any, etc.
How's that look? Complete?
(I'd develop a full BNF suitable for a parser, but that would get pretty
crazy, fast.)
Thanks.
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