[FFmpeg-devel] FATE filter tests

Clément Bœsch u at pkh.me
Mon Mar 17 11:24:36 CET 2014

On Sun, Mar 16, 2014 at 01:25:47PM -0700, Timothy Gu wrote:
> 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

As you said below, these are for testing the different pixfmts; it is
useful for filters with multiple code path for each pixel formats. Also
note that those tests are very slow to run.

> * vsynth tests with framecrc, and

This is the most straightforward way of adding tests.

> * vsynth tests with video_filter.

I think this is mostly historical. Also note that video_filter is used by
the pixfmts test. I suppose it was kept for having the test common between
the two.

Also note that the video_filter version only provides a single md5 for the
whole output while framecrc gives more hints in case of mismatches (like
which frame failed).

Having video_filter output framecrc might be lead to too large reference
files (there are tons of pixel formats for some filters). On the other
hand, replacing framecrc tests with video_filter will loose some

> 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?

Overlay needs multiple input so I suppose it's a special case.

> 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?

Maybe faster, less size overhead, which will probably grow a lot in case
of pixfmts tests.

Clément B.
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