chaptinator

Add chapters on scene changes to videos (e.g. slide changes in presentations)

Install

chaptinator requires ffmpeg to be installed on your system and for it to be in PATH. Follow the instructions on https://ffmpeg.org/ and make sure the commands ffmpeg and ffprobe are available in your favorite shell (bash, zsh, Powershell, ...).

Then install this package via pip. For a global installation use

sudo pip install chaptinator

and for a user-local installation use

pip install --user chaptinator

Usage

chaptinator VIDEO [-t TITLE] [-a AUTHOR] [-c CHANGE_THRESH] [-s] [-r] [-v] [-o] [-d] [-m METADATA_FILE]

-t TITLE sets the title in the metadata (default: filename)

-a ARTIST sets the artist in the metadata

-c CHANGE "value between 0 and 1 to indicate a new scene; a low value reflects a low probability for the current frame to introduce a new scene, while a higher value means the current frame is more likely to be one" -- https://ffmpeg.org/ffmpeg-filters.html#select_002c-aselect

-s scales the tagged result video to a height 720 while keeping the aspect ratio

-r reduces the framerate to 5fps, which is optimal to save bandwidth when powerpoint slides are the sole video content. Lower values cause problems with some browser video players

-o activates the ffmpeg tune 'stillimage' that lowers the deblocking filter, optimizing for still images like slides

-v converts the audio to MP3 with VBR (Variable BitRate) and a quality setting of 8, which is optimal for speech with relatively long segments of silence. (Lame is compiled into the standard ffmpeg library while the Frauenhofer AAC, which supports VBR, is not)

-d downmixes both audio channels into a single mono audio channel

-m METADATA_FILE disables the cut detection and instead uses the provided metadata file. This file has to have the structure described in https://ffmpeg.org/ffmpeg-formats.html#Metadata-1

Example

# increase cut detection threshold to 0.4, scale the video and reduce framerate
chaptinator foo.mp4 -t "Video Title" -a "Author Name" -c 0.4 -s -r

# read cuts from metadata file
chaptinator foo.mp4 -m metadata.txt

Use Cases

chaptinator could be used to add chapters to presentation slides that were recorded in PowerPoint and exported as video.

But of course it works with any video file that has cuts in it, just adjust the -c parameter to your preference.