Simply restore your backup.
If you don't make backups that is a bad habit that you ought to change immediately. In the alternative, then manually revert the files that you changed and your bootanimation will work again. If it doesn't seem to, then wipe your system cache from recovery mode.
If the problem persists, I would suggest that you didn't really revert all of the files that you changed. Check the file permissions and investigate what else your app may have changed on your behalf. In the worst case you can start over by writing a full stock firmware image to your phone. A lot more painful than restoring a backup that would reflect how your phone was four hours ago. But a certain lack of planning will limit choices that way.
As to the boot animation per se, Samsung requires a .qmg animation file, while most apps use a bootanimation.zip formatted file. Ergo you usually need to convert your .zip file to a qmg. Or modify your kernel to use the .zip format. There are lots of existing threads that explain in detail how to do either which you would know if you had done a search before posting. I would suggest that it is always in your own interest to do at least a quick search first, if only so that you can pose more informed questions.