Unfortunately, some browser versions (notably the 32-bit version of Firefox) are sometimes unable to handle the task of converting high-resolution video files, breaking out with an "out of memory" message such as the "out of memory undefined" message you might have seen in Clipchamp.
To solve this issue, we generally recommend to use Google Chrome to run Clipchamp. Chrome does not suffer from this problem and will perform more reliably than Firefox, Edge or Safari.
Alternatively, you can also upgrade Firefox from its 32-bit version to its 64-bit version to use Clipchamp in there. 64-bit Firefox will perform more reliably than 32-bit Firefox.
To install 64-bit Firefox, please see this Mozilla support article - https://support.mozilla.org/en-US/kb/switch-32-bit-64-bit.