---

name: yt-burnin-upload description: Download best-quality YouTube video/audio, burn in Korean subtitles (single line), then upload via YouTube Data API with Korean-translated title/description and unlisted privacy. Use when a user wants a hard-subbed version uploaded to a YouTube archive account.

yt-burnin-upload

Overview

Create a high-quality hard-subbed video for an archive account with Korean-only subtitles (single line).

Prerequisites

This skill requires a Korean subtitle file (ko.srt). If you don't have one, use yt-subs-whisper-translate first:

python3 yt-subs-whisper-translate/scripts/yt_subs_whisper_translate.py "<YOUTUBE_URL>"

This will generate ko.srt in the output folder, which you can then use with this skill.

Quick start

python3 scripts/yt_burnin_upload.py "<YOUTUBE_URL>" --ko-srt path/to/ko.srt

Workflow

1. Generate Korean subtitles using yt-subs-whisper-translate (if not already available).
2. Download best-quality video/audio.
3. Validate subtitle inputs (single-line cues).
4. Burn subtitles with ffmpeg (auto-scaled for resolution).
5. Translate metadata to Korean.
6. Upload via YouTube Data API (TODO).

Step 1: Download best-quality source

yt-dlp -f "bv*+ba/b" -o "source.%(ext)s" "<URL>"

Step 2: Prepare subtitle files

Inputs:

• ko.srt / ko.vtt for Korean output.

Rules:

• One line per cue, no line breaks.
• Do not shorten or summarize; split long cues by time if needed.

English subtitles are intentionally not burned in.

Step 3: Burn in subtitles

The script automatically detects video resolution and scales font size accordingly:

Resolution	FontSize	MarginV
720p	12	35
1080p	15	50
1440p	20	65
4K+	27	90

Example (1080p):

ffmpeg -i source.mp4 \
  -vf "subtitles=ko.srt:force_style='FontName=Noto Sans,FontSize=15,Outline=2,Shadow=1,Alignment=2,MarginV=50'" \
  -c:a copy burnin.mp4

See references/burnin-style.md for recommended styles.

Troubleshooting burn-in errors

If ffmpeg fails, check:

• Font not installed: Install Noto Sans via brew install font-noto-sans (macOS)
• Invalid SRT format: Ensure single-line cues, no internal line breaks
• Disk space: Burn-in creates a new video file
• Codec issues: Some codecs may require re-encoding

Step 4: Translate metadata

Translate title and description to Korean with Codex CLI. See references/upload-metadata.md for the translation prompt.

Step 5: Upload via YouTube Data API (TODO)

Upload as unlisted. OAuth client secret configuration is TODO.

See references/upload-metadata.md for upload rules.

Expected outputs

• source.<ext> best-quality download
• burnin.mp4 hard-subbed output ready for upload
• metadata_ko.json translated title and description