subtitles-and-text-effects

Subtitles & Text Effects · Subtitles & Text Effects

Put four styles in one ASS file at the same time:Sub(bottom subtitles) · Hook(pop-up large text effects) · Tag(top-left sticker) · CTA(call-to-action button). Script:scripts/make_subs.py。

Part of ecommerce-video-skills

Inputs Inputs

Timeline JSON (ffmpeg-auto-assemble automatically generated build/timing.json), or write your own:

{"size": [1080, 1920], "cues": [
  {"start": 0.10, "end": 2.70, "text": "冰水撑不到中午？", "style": "Hook"},
  {"start": 0.15, "end": 2.60, "text": "冰水不到中午就**变温**了？", "style": "Sub"},
  {"start": 0.00, "end": 17.0, "text": "AURA 保温杯", "style": "Tag"},
  {"start": 14.2, "end": 17.0, "text": "点击下方链接 ›", "style": "CTA"}]}

Markup Markup

Syntax	Effect
`关键词`	Change the keyword to the highlight color (default warm yellow)
`Fill with ice cubes in the morning	and the ice cubes are still there by evening`

Steps Steps

Each subtitle ≤ 14 Chinese characters (1080 wide ≈ one line); if longer, use | to split.
Highlight only 1 keyword per subtitle; text effects ≤ 10 characters, used only for the hook and key selling points.
Generate:python scripts/make_subs.py build/timing.json -o build/subs.ass --srt build/subs.srt
Burn in:ffmpeg -i in.mp4 -vf "ass=build/subs.ass" -c:a copy out.mp4
If the platform supports uploading subtitle files (such as YouTube / some ad platforms), also deliver .srt。

Safe zones Safe zones (rule-of-thumb values, subject to actual device testing)

Bottom about 20%: title copy, product card, shopping cart → subtitles MarginV default 26% height
Right side about 15%: like/comment/share buttons → left and right margins 70px, do not place important information near the right side
Top about 8%: status bar/search → place the Hook at 13% height
Use python skills/platform-spec-export/scripts/export_platform.py video.mp4 --safe-preview safe.png(run in the repository root directory) overlay check

Style customization

Edit make_subs.py in header(): font size is calculated as a proportion of the frame height (applicable to 9:16 / 1:1 / 16:9), colors are ASS &HAABBGGRR. Fonts are automatically detected (Noto Sans CJK SC / Source Han Sans / PingFang / Microsoft YaHei), and you can also --font "思源黑体 CN"。

Prompt template Prompt template

把这段口播稿拆成短视频字幕：每条 ≤14 字，超过用 | 分段；每条最多 1 个关键词用 **加粗**；
另外为钩子镜头和最强卖点各写 1 条 ≤10 字的花字。输出 JSON cues（start/end 先留空）。口播稿：{…}

Checklist Checklist

Subtitles do not cover the product subject and do not enter the bottom 20% / right-side button area
At most 2 lines per screen; keyword highlights ≤ 1
Check typos/brand spelling; numbers match the voiceover
Chinese fonts are installed (otherwise boxes will appear)

Common issues and fixes Failure fixes

Issue	Fix
Chinese displays as boxes	Install a CJK font (`apt install fonts-noto-cjk`) or `--font` specify an installed font
`No such filter: 'ass'`	ffmpeg was not compiled with libass; switch to the official/distribution full version of ffmpeg
Path contains a colon and reports an error (Windows)	Use a relative path or write `C:` as `C\:`; the script already escapes automatically
Subtitles and audio are out of sync	Generate timing using the actual voiceover duration (`assemble.py` already handles this automatically)
Subtitles are too small	Adjust `header()` in `sub = round(h * 0.037)` the coefficient of