[FFmpeg-devel] FATE filter tests

[Timothy Gu]

Hi all,

Recently Iḿ trying to add some fate tests for video filters, and I can
see that there are two kinds of filter tests:

* pixfmts tests
* vsynth tests with framecrc, and
* vsynth tests with video_filter.

It is obvious that pixfmts tests test all the pixfmts the filter
supports, but I can also see that with filters e.g. overlay you use
multiple vsynth framecrc's instead. What is the rationale behind that?

Also some tests e.g. crop use video_filter instead of framecrc.
framecrc has higher precision than video_filter, which uses md5. What
advantage does using video_filter have?

Timothy