ffmpeg join two mp4 videos one after another

Question

I've got 2 videos I want them to join into one video using ffmpeg. I am running these commands in Java so I need it to use the command line so no other programme solutions apply. I have tried many different ways but non seem to work. So i got a video of 35 seconds and one of 5 seconds I need a output of 40 seconds this never seems to happen. if anyone could help it would be greatly appreciated

Answer 1

I have found a solution to this myself and I believe this could be useful for other people as it took me a lot of time to find it. You can not join two mp4 together through ffmpeg. You can however convert the videos to a .ts file then join them one after another and convert it back to a mp4. This sounds complicated but the ffmpeg is pretty simple.

ffmpeg -i vid1.mp4 -c copy -bsf h264_mp4toannexb  vid1.ts
ffmpeg -i vid2.mp4 -c copy -bsf h264_mp4toannexb  vid2.ts
ffmpeg -i "concat:vid1.ts|vid2.ts" -c copy output.mp4       

So the first 2 lines convert the videos to a .ts file and the 3rd line joins them and makes a .mp4 and obvously you can delete the .ts files if you are running this in a programming language like java.

Hope someone finds this useful as I spent a greqat deal of time trying to find this solution.