"My MP4 Trimmer" allows you to rapidly scrub through an MP4 video, easily select start or end trim points and then extract that portion of the MP4 into a new file. Your resulting MP4 is never re-compressed, so there is no generation loss in quality. The limiting factor for how fast "My MP4 Trimmer" can trim an MP4 is the speed of your storage media, The faster your drive is (like an SSD), the quicker the trimming is.
Unlike other trimming apps, "My MP4 Trimmer" only allows you to set your trim points at MP4 Key frames.
The upside of trimming only at Key frames is that scrubbing through an MP4 is very fast, it is 100% repeatable in selecting start or end points and it solves the issue of an MP4 losing audio synch when played on other platforms.
The downside of only trimming at Key frames is that your trim point times are limited by how frequently the MP4 encoder set the Key frames at (minimum of 4 key frames needed). So if an MP4 was created with Key frames at 10 second intervals, you can only trim it at 10 second intervals.
Lastly if you are having problems, please send me an e-mail with your issue. I will do my best to resolve your problem ASAP. If you post something in the comments section of the Apple store site, I can not respond to it as Apple does not allow that. So contact me directly if your having problems.
