[FFmpeg-devel] [PATCH]

[Werner Robitza]

On Wed, May 15, 2019 at 4:55 PM Gyan <ffmpeg at gyani.pro> wrote:
> On 15-05-2019 05:06 PM, Werner Robitza wrote:
> > On Wed, May 15, 2019 at 11:36 AM Gyan <ffmpeg at gyani.pro> wrote:
> >> Which lines in the CLI help?
> > SWScaler AVOptions:
> >    -sws_flags         <flags>      E..V..... scaler flags (default bicubic)
> >     ...
> >    -src_format        <pix_fmt>    E..V..... source format (default yuv420p)
> >    -dst_format        <pix_fmt>    E..V..... destination format (default yuv420p)
> >    -src_range         <boolean>    E..V..... source is full range (default false)
> >    -dst_range         <boolean>    E..V..... destination is full range
> > (default false)
> >
> >> I don't see any constants set in the AVOptions struct. Can you share a command line where you could set this option using a string?
> > I was just going by the help printed above, including the default. If
> > a string is not valid, which values are?
> The help function fetches the string name for the default value but the
> user has to input an integer.
>
> The pixel formats are declared in an enum in libavutil/pixfmt.h. The
> integers correspond to their index in that list.

That seems very bad in terms of usability. Is there a particular
reason why the "-pix_fmt" option can parse these values, but swscaler
not? In fact, most (if not all) other options that accept a finite set
of arguments don't use numbers in that way, but strings.
I can add the integers to the documentation as a lookup table, but it
feels weird doing so.

> >>> +If set to 1, source range will be full range.
> >> Mention the range of values possible and their meaning.
> > I don't understand, as no other values are possible. Well, 0 is
> > possible but meaningless since it's default; 1 indicates "true".
> Sure, if the option name was is_src_range_full. But src_range allows you
> to specify a range. So, even though there are only two, better to
> mention the allowed values and their meaning.

Ok. Will send an update.