Original video file renamed, no encoding done though thumbnail is generated

When I create a new video with FFMPEG, instead of creating a new encoded video, all it does is rename the original video file (delete the Original Video is not enabled). The parameters I specify to modify the original video do not alter the video in any way - all that results is the original video being renamed. Both the original and encoded fields in the node type point to the renamed file (neither has a reference to the original file, nor does the original file exist in the upload directory after ffmpeg is run). However, the thumbnail generation works exactly as expected.

I have tried running ffmpeg immediately upon node creation and at cron run. One thing I noticed that might be tied to the problem is that when I run cron manually, it seemingly stops during execution and just results in a blank page. However, when refreshing the status reports page it says the encoded video and thumbnail image were successfully created and that cron ran successfully.