ffmpeg: gapless video splitting and concatenation

For instance you have a big video file and want to split it onto several parts all.mpg. Splitting it on 1 sec parts:

ffmpeg -i all.mp4 -ss 0 -t 1 first-1-sec.mp4
ffmpeg -i all.mp4 -ss 1 -t 1 first-2-sec.mp4
ffmpeg -i all.mp4 -ss 2 -t 1 first-3-sec.mp4

After this you can want to check the result by combining these files together in one:

One alternative is:

ffmpeg -i "concat:first-1-sec.mp4|first-2-sec.mp4|first-3-sec.mp4" -c copy blah.mp4

But it works for me not always. So there’s also another one:

1. Creating files.txt:
   

   file first-1-sec.mp4
   file first-2-sec.mp4
   file first-3-sec.mp4

2. Running

   ffmpeg -f concat -i files.txt  blah.mp4

And here we’re!