Splitting an mpeg4 file into multiple parts with ffmpeg

I have a 5.3GB mpeg4 file (of the just released ‘From Bedrooms to Billions: Amiga Years‘ documentary about the Commodore Amiga – I haven’t watched it yet but may post a review later), and the size of this single file is giving me some issues 🙂

It’s too large for a FAT32 formatted flash drive, since the largest file you can store on that file system is 4GB. It’s also too large to burn to a 4.7GB single-sided DVD. So I could have reformatted a flashdrive to exFAT (I don’t think the PS4 reads NTFS drives, and my Mac won’t write to NTFS, at least not without other drivers), but the easiest option is probably to split the file to smaller parts.

Now, if you’ve done any video editing before, rendering 1080p video and any amount of transcoding to different formats takes a ton of time. I didn’t want to recode the video or change the format in any way, I just wanted to split the file.

Turns out ffmpeg will do exactly this, and to split into 2x 1hr15m smaller files only took a few minutes on my i7 Mac. I took suggestions from this question, and ended up with these two commands:

ffmpeg -i inputfile.mp4 -ss 00:00:00.0 -c copy -t 01:15:00.0 outputfile-pt1.mp4

ffmpeg -i inputfile.mp4 -ss 01:15:00.0 -c copy outputfile-pt2.mp4

The first one takes input from the start and for 1hr15mins writes to the output file, and the second starts from 1hr15min into the input file and writes the remainder from that point onwards to the second output file.

Final Cut Express 4 notes

I rarely use Final Cut Express, usually iMovie does everything I need. Whenever I come back to FCE though, I always forget how to do some of the simplest tasks. A few reminders for myself:

  • To add a transition between clips you need in and out points set first to define where the transition should start/end (on both of the clips between which you are adding the transition)
  • Double-click a clip in the timeline to load it into the viewer to edit it’s properties
  • Overlay videos by dragging each clip to a track in the timeline. You can resize, move and clip each overlaid video in the ‘Motion’ properties tab in the viewer
  • To use the Chroma Key effect to overlay a video, drag the Chroma settings tab out of the viewer, then use the ‘dropper’ to select the background color in the video clip