How can I efficiently convert MOV / MPEG-4 files for long term storage?

Question

I have a Canon 6D DSLR that I am shooting video on. The camera is set to capture 1280x720 60fps IPB MOV / MPEG-4 files. The video files are in the range of 250MB per minute of recording. I have literally no skills in video editing and at this point just capture important family events to potentially edit in the future. I understand compression and the loss of quality from a general perspective.

Is there a format or method that would be a reasonable trade-off between file size and quality beyond leaving the files in their existing state? Should I just leave them alone? Knowing that my DSLR has specific needs to write the file to a memory card immediately, it is understandable that it isn't in the optimal format for long term storage; so that is why I imagine an answer may exist to this question.

Related: Compress or convert .mov to lighter format

Answer 1

Although @stib's advice is sound, I disagree with "to get an appreciable size reduction you would have to throw away a lot of quality". Cameras have to compress on-the-fly, so they use constrained baseline mode, which is to say, they skip most of the tricks that H.264 codec uses to efficiently compress videos. If space isn't a pressing concern, keep them as-is. But if you'd like to recover some space, you can use ffmpeg, a command-line tool, to compress them while generally retaining quality.

ffmpeg -i input.mov -c:v libx264 -crf 12 -c:a copy -c:d copy -map 0 compressed.mov

CRF values in the range of 12 to 15 will give you a smaller video stream, generally by 25 to 40%. Perversely, if your scene has a lot of fine texture detail like a forest or pebbles or embroidered cloth..etc, then compressibility won't be high and using these CRF values will likely produce output which is larger than the source. Skip compression in these cases. For most scenes, filled with smooth gradients or nearly-flat shaded surfaces, compression should yield a smaller file with good quality.

Answer 2

Leave them as they are. If storage space is limited you could recompress them, but given that the files coming from the DSLR are already compressed, to get an appreciable size reduction you would have to throw away a lot of quality. As you're planning to edit them in the future - meaning another transcoding - this would be a last resort.

Buy more hard drives. And remember that if you haven't saved the files in two physically separate locations, you haven't saved them.