[FFmpeg-devel] [PATCH] avcodec/libvpxenc: add VP8 support for ROI-based encoding

Gyan ffmpeg at gyani.pro
Wed Feb 27 19:31:30 EET 2019

On 27-02-2019 10:32 PM, Derek Buitenhuis wrote:
> On 27/02/2019 13:48, Gyan wrote:
>> Huh. I haven't suggested removing anything.
>> I suggested *adding* a way for this feature to be useful for ffmpeg
>> users in the near-term. Who knows how long will it take for a decent
>> per-frame ROI filter, like the facedetect example mentioned in the
>> initial discussion.
> Apologies, I misread.
> As for an AVOption: That could get ugly, fast. What do you pass it?
> A string of ROI and offsets? That would balloon fast.
Yes,  a string. 4 integers and qp offset so either two more, in rational 
form, or a float.

There's already multiple interfaces accepting long multi-entry 
multi-valued arguments, whether custom ones in filters like curves or 
pan, or x264opts, or with the assistance of an existing key-value parser 
like x264-params. Unless the plan is to allow only machine-generated 
ROIs, some form of manual user specification will be needed, and that 
option will have to be prepared to accept and parse such a string.


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