[FFmpeg-devel] [PATCH] avfilter/vf_fps: extend support for expressions

[Gyan Doshi]

On 2021-06-20 01:29, James Almer wrote:
> On 6/19/2021 4:56 PM, Gyan Doshi wrote:
>>
>>
>> On 2021-06-05 21:22, James Almer wrote:
>>> +static const double ntsc_fps = 30000.0 / 1001.0;
>>> +static const double pal_fps = 25.0;
>>> +static const double qntsc_fps = 30000.0 / 1001.0;
>>> +static const double qpal_fps = 25.0;
>>> +static const double sntsc_fps = 30000.0 / 1001.0;
>>> +static const double spal_fps = 25.0;
>>> +static const double film_fps = 24.0;
>>> +static const double ntsc_film_fps = 24000.0 / 1001.0;
>>
>> Sorry, I missed this before you applied it but what's the q- and s- 
>> prefixed standards with identical rates?
>> I can't find any specs or docs online.
>
> It's taken from video_rate_abbrs in libavutil/parseutils.c
> The description is "VCD compliant" for q and "square pixel" for s.

Right. So originally, these labels were created to denote a distinct 
*permutation* of resolution and framerate, in ba2a8cb40b
They are not part of any distinct variant of any standard or convention, 
outside of ffmpeg, and frankly not even internally.

These should be removed to avoid any confusion.

Regards,
Gyan