ffmpeg -i /sdcard/path/movie.mp4  -ss 00:00:06.000, -t  00:00:05.270, -c:a aac -c:v libx264 /sdcard/path/file1.mp4
ffmpeg -i /sdcard/path/movie.mp4  -ss 00:00:12.000, -t  00:00:04.370, -c:a aac -c:v libx264 /sdcard/path/file2.mp4
ffmpeg -i /sdcard/path/movie.mp4  -ss 00:00:23.000, -t  00:00:03.133, -c:a aac -c:v libx264 /sdcard/path/file3.mp4
ffmpeg -i "concat:/sdcard/path/file1.mp4|/sdcard/path/file2.mp4|/sdcard/path/file3.mp4" -c:a aac -c:v libx264 /sdcard/path/output.mp4

ffmpeg -i input1.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate1.ts
ffmpeg -i input2.mp4 -c copy -bsf:v h264_mp4toannexb -f mpegts intermediate2.ts
ffmpeg -i "concat:intermediate1.ts|intermediate2.ts" -c copy -bsf:a aac_adtstoasc output.mp4