Hi,

>>>>> On 2022-05-18 11:34 pm, Jan Ekström wrote:
>>>>>> This enables overriding the rotation as well as horizontal/vertical
>>>>>> flip state of a specific video stream on either the input or output
>>>>>> side.
>>>>>
>>>>> Since rotation, flip and scale are stored in a single data structure,
>>>>> how about a single option i.e. -display "rotate=90,flip=hv,scale=2"
>>>>
>>>>
>>>> I did think about that, and I even implemented AVDict based options for ffmpeg.c in a branch. But then pretty much got tired of lack of AVOption automation (f.ex. for the flip flagging etc), and decided that since these are relatively basic and simple, the non-generic option for this could be just three options in the initial submission.
>>>
>>> In the end I did implement this with a single dict-based thing in a
>>> branch but never got to posting it to this thread:
>>> https://github.com/jeeb/ffmpeg/commits/ffmpeg_c_display_matrix_with_dicts
>>>
>>> So for the positive: Now it's all in a single option so it's clear
>>> that it's defining a single structure.
>>> And the negative: Needs a struct definition, struct, AVOption list,
>>> AVClass and actually if you already made a dict out of the options
>>> before, as the functions will free the original after usage and
>>> generate a new one, it destroys the life time expectations of the dict
>>> and thus it is just simpler to copy the dict when entering the
>>> function (I think there is an arguments string based API which might
>>> or might not actually be simpler for this case).
>>>
>>> So yea, not sure if I prefer this version.
>>
>> Ping.
>>
>> Did this stall for a reason? How can we iterate on it?
> 
> Since the rotation/flip/scale hints are stored in a single data structure, I prefer a single user option to set those values.

attached patch allows for printing the arguments of the new -display_rotation (or any) option.

I wrote this in jeeb's github branch [1] where it applies on-top. Didn't test with FFmpeg/HEAD as this still needs cleanup anyways.
Never touched this whole options thing before, I guess there's lot to complain about...

-Thilo

[1] https://github.com/jeeb/ffmpeg/commits/ffmpeg_c_display_matrix_with_dicts