[FFmpeg-devel] [PATCH]

[Gyan]

On 16-05-2019 06:29 PM, Werner Robitza wrote:
> On Wed, May 15, 2019 at 11:23 PM Michael Niedermayer
> <michael at niedermayer.cc> wrote:
>> On Wed, May 15, 2019 at 11:13:57PM +0200, Werner Robitza wrote:
>>> 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.
>> where exactly is a end user facing interface using integers for pix_fmt
>> in place of named identifers, can you show an example command line ?
> I checked again, and when you try this, this is printed:
>
>> Directly using swscale dimensions/format options is not supported, please use the -s or -pix_fmt options
>> Error parsing option 'src_format' with argument 'yuv420p'.
> So this should actually be removed from the CLI options entirely, or?
> (And the documentation.)
Strictly speaking, the doc page isn't for CLI use only. A note has been 
added to indicate which options are API only.

Gyan