Subtitles

Subtitles are burned into the video frames with Pillow and OpenCV.

Pillow handles TrueType fonts and UTF-8 correctly, so accented text renders properly. OpenCV's default Hershey fonts are ASCII-only and are not used for final subtitle text.

Static subtitles

The default subtitle path uses a sliding word window centered on the current word.

Dynamic subtitles

Enable the dynamic style with:

--dynamic-subtitles

Dynamic subtitles use fixed word blocks. The block stays in place while the current word is highlighted. When speech crosses into the next group, the block advances.

Subtitling the full video

--subtitles-only burns subtitles into the entire source video instead of generating Shorts:

poetry run python -m shortificator \
  --input my_video.mp4 \
  --subtitles-only \
  --dynamic-subtitles

In this mode:

• there is no cropping and no LLM analysis — the only change is the burned-in subtitles;
• the original resolution and frame rate are kept (--fps is ignored);
• the audio track is stream-copied untouched (falling back to AAC 192k only if the source codec doesn't fit the MP4 container);
• the output is a single output/{name}_subtitled.mp4;
• the style follows the same rules as Shorts: sliding-window subtitles by default, fixed blocks with --dynamic-subtitles, and all style flags below apply;
• --srt still writes the full-video .srt, and --transcript can reuse a saved transcript;
• --clip and --candidates cannot be combined with it.

Style flags

Flag	Default	Description
--sub-font	auto-detected	path to a .ttf font
--sub-font-size	78	starting font size in pixels
--sub-color	255,255,255	normal word color
--sub-highlight-color	255,224,64	current word color
--sub-stroke-color	0,0,0	outline color
--sub-stroke-width	5	outline width
--sub-y-ratio	0.74	vertical position
--sub-max-lines	2	maximum subtitle lines
--sub-words-per-chunk	4	words per dynamic block
--sub-no-uppercase	off	preserve original casing

Colors accept R,G,B or #RRGGBB.