Compare results to baseline.

Being able to define a baseline test result, and then compare new results to baseline.

That way we can use it to determine if new versions of ffmpeg produce the same result as old versions (or across platforms).

No files, tests, or entry points are identified in the issue. Start by locating how test results are currently produced and stored, then determine how a baseline could be defined and compared across ffmpeg versions or platforms. Done means the project can compare new results with a selected baseline.

Written by the indexing model from the issue text.