A very common use case is that you don't want to waste time using a video editor that requires you to open it up and manually import the video clip and audio clip, then manually delete the old audio track and import the video and new audio. That's too much work and time since we don't want to go through the hassle.
ffmpeg is our solution, all we have to do is specify 3 variables and we're done!
-i Windows2019-Server-Noaudio.mp4 is our in........
yum -y install gmp-devel mpfr-devel libmpc-devel glibc-devel glibc-devel.i686 zip unzip jar
Download, untar, configure, compile and install GCC
tar -zxvf gcc-5.5.0.tar.gz
Now you need to cleanup th........
When things go wrong your video is basically unplayable or the first video plays fine and then freezes when moving on to the next. Generally if both videos weren't produced with the exact 100% same settings you will have issues. You can try the basic concat but it often won't work right.
Solution for me:
My example uses 3 videos in total so "n=3" and a=1 to include audio.
ffmpeg -threads 12 -i file1.mp4 -........
#if you have nvidia make sure you install the nvidia-cuda-toolkit so hardware acceleration can be used
tar -jxvf ffmpeg-3.3.2.tar.bz2
install prefix /usr/local
source path ........