Compression error is reported as being very high

[nfrechette]

Some UE4 animation sequences can have a sample/frame rate that isn't a whole number. e.g. 5 frames in 4 seconds. This does not usually happen but old sequences might have been impacted by an import bug sometime in the past.

ACL rounds the frame rate to a whole number and uses it to optimize the error but as a result, it does not measure the error like UE4 does. Even though the ACL reported error will still be very low, UE4 might report a high error. This happens because they disagree on where to measure the error in the animation sequence. As such, even though UE4 might report a high error, the sequence itself should be very accurate regardless and any error is unlikely to be visible to the naked eye.

A workaround is to re-import those impacted sequences to make sure their frame rate is a whole number (e.g. 30 FPS).

ACL will implement floating point sample rate support at some point in the future, this is tracked by this issue: nfrechette/acl#123