Add chapters to mp4

1. Get the frame rate of your source video (assuming you have 30fps and the video is called input.mp4 for later steps)
2. Calculate Timebase value
   
   • Timestamp fps*1000 => Timestamp 30000
   • Timebase 1/Timestamp => Timebase 1/30000
3. Calculate all start and end timestamps:
   • Note: timestamp 02:03:04.005 => 2 hours, 3 minutes, 4 seconds, 5 millisecond
   • timestamp = (hours*60^2 + minutes*60^1 + seconds*60^0 + millisecond*10^-3) * timebase
   • END Timestamp = Starting Timestamp of the following chapter - 1
   • Timestamp for this example: 221520150
   • And if this is the timestamp for chapter n, the end timestamp of chapter n-1 is: 221520149
4. Use the following template to create a text file named meta.txt

   ;FFMETADATA1
   TITLE=ENTER_VIDEO_TITLE_HERE
   PRODUCER=ENTER_PRODUCER_HERE
   [CHAPTER]
   TIMEBASE=1/30000
   START=0
   END=221520149
   title=Chapter 01 - ENTER_TITLE_OF_CHAPTER_01
   [CHAPTER]
   TIMEBASE=1/30000
   START=221520150
   END=443020300
   title=Chapter 02 - ENTER_TITLE_OF_CHAPTER_02

5. Use ffmpeg to combine the metadata and source video:

   ffmpeg -i input.mp4  -i meta.txt -c copy -map_metadata 1 output.mp4

6. Open output.mp4 using vlc and verify that all timestamps are correct.