[FFmpeg-devel] [PATCH 1/2] ffmpeg: add display_{rotation, hflip, vflip} options

[Jan Ekström]

On Thu, May 19, 2022 at 9:27 AM Jan Ekström <jeebjp at gmail.com> wrote:
>
> On Thu, May 19, 2022, 07:21 Gyan Doshi <ffmpeg at gyani.pro> wrote:
>>
>>
>>
>> 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.

Jan