VideoCaptioner CLI

AI-powered video captioning: transcribe speech → optimize subtitles → translate → burn into video with beautiful styles.

When to use

• User wants to add subtitles to a video
• User wants to transcribe audio/video to text
• User wants to translate subtitles to another language
• User wants to customize subtitle appearance (colors, fonts, rounded backgrounds)
• User wants to download and subtitle online videos

Before you start

Always run videocaptioner <command> --help first to check the latest options and defaults before executing a command. The examples below are common patterns, but --help is the source of truth.

• Install: pip install videocaptioner
• FFmpeg required for video synthesis (brew install ffmpeg on macOS)
• Free (no API key): transcription (bijian/jianying), translation (Bing/Google)
• Requires LLM API key: subtitle optimization, subtitle re-segmentation, LLM translation. Set via OPENAI_API_KEY env var or --api-key flag

Common scenarios

1. Give a Chinese video English subtitles (one command, all free)

videocaptioner process video.mp4 --asr bijian --translator bing --target-language en \
  --subtitle-mode hard --quality high -o output.mp4

2. Transcribe a video to SRT (free)

videocaptioner transcribe video.mp4 --asr bijian -o output.srt

# Output as JSON format to a directory
videocaptioner transcribe video.mp4 --asr bijian --format json -o ./subtitles/

3. Translate existing subtitles

# Free Bing → English, bilingual output with translation above original
videocaptioner subtitle input.srt --translator bing --target-language en --layout target-above -o translated.srt

# Free Google → Japanese, translation only (discard original text)
videocaptioner subtitle input.srt --translator google --target-language ja --no-optimize --layout target-only -o output_ja.srt