Investigate acceleration options for FFmpeg's v360 filter

Description

Context: !191 (comment 2912628639)

FFmpeg's v360 filter that we use is a CPU filter, and we need hardware acceleration to have okay transcoding performance. remap approach is one of the options (with its remap_opencl HW-accelerated counterpart), but it requires creating pixel maps.

This may or may not be something we want to do, we should investigate the level of effort and applicability

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Additionally, there have been some efforts to create v360_opencl and v360_vulkan, both of which should work on Orange Pi in theory, but they are incomplete (ffmpeg-devel thread). If this can be incorporated, it'll probably be a much better option than using remap.

Scope

• Comment conclusions
• Update WIP 0007, if applicable