Resizing Movies with ffmpeg

Scaling down Full HD from 1920x1080 to 960x540:

ffmpeg -i input.mp4 -s 960x540 -c:a copy output.mp4

-i ... input
-s ... scale
-c ... codec

Compressing with H.2645

ffmpeg -i input.mp4 -vcodec libx265 -crf 28 output.mp4

crf ... video quality, lower value means better quality

Concatenating videos with the Quicktime Player requires unnecessary decoding/encoding, with takes time and computational resources.

Solution: Concatente Files von FFMPEG

https://trac.ffmpeg.org/wiki/Concatenate

Using ffmpeg

1. Create a list: mylist.txt

   file '/path/to/file1.mp4'
   file '/path/to/file2.mp4'
   file '/path/to/file3.mp4'

2. Run ffmpeg ffmpeg -f concat -i mylist.txt -c copy output.mp4

Troubleshooting

[concat @ 0x7fc407904080] Unsafe file name '2008-08-05 21_38_08.mov' mylist.txt: Operation not permitted

If filenames have a spaces, it is necessary to use the -safe 0 option.

mylist.txt

file '/path/to/file 1.mp4'
file '/path/to/file 2.mp4'
file '/path/to/file 3.mp4'

ffmpeg -safe 0 -f concat -i filelist.txt -c copy output.mp4

Make a list of all .mp4 files in a directory:

printf "file '%s'\n" *.mp4 > filelist.txt

QuickTime Player Version can record movies. If the recording process in interrupted by battery running out, or the computer being closed and put to sleep, the video file is store at the following location: ~/Library/Containers/com.apple.QuickTimePlayerX/Data

QuickTime Player Version: 10.4