[FFmpeg-devel] [PATCH] Document the preset files system

The Wanderer inverseparadox
Thu Oct 2 01:20:28 CEST 2008

Stefano Sabatini wrote:

> On date Sunday 2008-09-28 20:27:31 -0400, The Wanderer encoded:
>> Stefano Sabatini wrote:
>>> Hi, as in subject.
> [...]
>> Beyond that I can't really improve this, largely because I don't
>> understand it well enough for the degree of rewriting it would
>> require. (I think it's talking about automatically choosing a
>> preset based on the specified codec name and on something else, but
>> I have no real idea what the else is from a user perspective, and I
>> don't see where in the code this paragraph comes from in the first
>> place.)
>> Honestly, I would prefer to rewrite (and reorganize) these last
>> three paragraphs entirely, if I were certain that I understood them
>> correctly.
> I rephrased almost entirely the whole text, trying to apply the
> proposed corrections, I think it should be more clear now, please
> check it again.

Sorry for the delay. Here goes.

> +The argument of these options identifies a preset file according to
> +the following rules.

The use of the singular "argument" and the plural "options" seems a
little off, though I understand what you mean and can see how it could
be said to make sense. Unfortunately just using both singular or both
plural becomes either more-confusing or outright inaccurate. Something
like "The argument passed to one of these options is used to identify",
et cetera... still has problems, but avoids that *particular* problem.
I'm not sure it's really better, either.

If anyone else has any suggestions for how to improve this, I'd
appreciate hearing them.

> +First ffmpeg searches for a file named @var{ARG}.ffpreset in the
> +directories @file{$HOME/.ffmpeg}, @file{/usr/local/share/ffmpeg} and
> + at file{/usr/share/ffmpeg} in that order. For example if the argument is
> + at code{libx264-max} it will search for the file
> + at file{libx264-max.ffpreset}.

It feels as if there should be a comma after "First", but adding that
would conflict with the use of a comma-separated list later in the
sentence, so it's probably best to leave it alone.

Need two commas in the second sentence - after "example" and after the
first @code section.

> +If a file is not found applying the previous rule, then ffmpeg will

This seems awkward, but I don't have a good way to fix it while keeping
the same approach. I think something like "If no such file is found,"
might work, though.

> +search for a file named @var{CODEC_NAME}- at var{ARG}.ffpreset in the
> +above-mentioned directories, where @var{CODEC_NAME} is the name of the
> +currently selected codec with the type specified by the command
> +option. For example if the command is @code{-vpre max} and the
> +currently selected video codec is @code{libx264}, then it will search
> +for the file @file{libx264-max.ffpreset}.

Again, need comma after "example".

Clarification question: does "with the type specified by the command
option" (which should be "command-line option", naturally) refer to the
type of codec (i.e., which type of codec is used depends on the
command-line option, e.g. '-vcodec foobar'), or to the type of preset
(e.g., "max" vs. "normal")?

If the former, I would say something like "the currently selected codec
as specified on the command line", and possibly mention '-vcodec'
explicitly at some point ("specified by the -vcodec option'?).

If the latter, I don't think I would include the part of the sentence
after "codec" at all; the matter seems clearly enough explained by the
example, and I mentioning it here doesn't seem to have any benefit and
might be confusing.

> +Finally if the above rules failed and the argument specifies an
> +absolute pathname, it will search for that filename. This way you can
> +specify the absolute and complete filename of the preset file, for
> +example @file{./ffpresets/libx264-max.ffpreset}.

Need a comma after "finally".

Other than that, looks good enough to me.

       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.

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