# Can Claude Video Transcribe Videos Without Existing Captions? A Complete Guide > Yes Claude Video transcribes videos without captions using Whisper fallback. Get accurate transcriptions effortlessly. Learn how in our complete guide. - Repository: [bradautomates/claude-video](https://github.com/bradautomates/claude-video) - Tags: how-to-guide - Published: 2026-07-28 --- **Yes, Claude Video can transcribe videos without existing captions by automatically falling back to OpenAI or Groq Whisper transcription when no embedded or fetched subtitles are available.** Claude Video is an open-source tool that enables AI-powered video analysis through the Claude API. When processing videos that lack existing caption files, the system seamlessly transitions to on-demand audio transcription, ensuring you can extract text content from any video source. ## How the Transcription Fallback Works The `/watch` skill in [`skills/watch/scripts/watch.py`](https://github.com/bradautomates/claude-video/blob/main/skills/watch/scripts/watch.py) implements a robust two-stage pipeline that prioritizes existing captions before invoking Whisper. ### Step 1: Checking for Existing Subtitles First, `download.fetch_captions()` attempts to retrieve any available subtitle files from the video source. If the function discovers a VTT file, it parses the content using `parse_vtt` and populates the transcript segments. If no subtitle file is found, the `subtitle_path` entry remains `None` and the transcript stays empty. ### Step 2: Triggering the Whisper Fallback After the initial fetch, [`watch.py`](https://github.com/bradautomates/claude-video/blob/main/watch.py) evaluates whether `transcript_segments` is empty. If no captions were discovered **and** the user has not disabled transcription via the `--no-whisper` flag, the script proceeds to the Whisper fallback mechanism. This detection logic appears at lines 39-57 of [`skills/watch/scripts/watch.py`](https://github.com/bradautomates/claude-video/blob/main/skills/watch/scripts/watch.py). ### Step 3: Audio Extraction and Transcription The system prepares the audio through several sub-steps managed by [`skills/watch/scripts/whisper.py`](https://github.com/bradautomates/claude-video/blob/main/skills/watch/scripts/whisper.py): 1. **API Key Resolution**: `whisper.load_api_key()` checks for a `GROQ_API_KEY` environment variable first, falling back to `OPENAI_API_KEY`. If neither is found, the user is prompted to run the setup helper (lines 65-71). 2. **Audio Processing**: `whisper.extract_audio()` invokes `ffmpeg` to generate a mono 16 kHz MP3 at approximately 64 kbps. This format complies with Whisper's upload constraints while minimizing file size (lines 15-31). 3. **Chunked Upload**: `whisper.transcribe_video()` handles the API communication. For files exceeding 24 MiB, the audio is automatically chunked. The function posts the data to the selected endpoint (Groq or OpenAI), receives a verbose JSON response, and converts the results into the internal `{start, end, text}` segment format (lines 37-45, 51-66). ### Step 4: Integrating the Transcript The returned segments are filtered to match any user-specified time range using `--start` and `--end` parameters. The final report explicitly labels the transcript source as "whisper (groq)" or "whisper (openai)" to indicate the transcription provider used. ## Prerequisites for Transcribing Videos Without Captions To successfully transcribe videos that lack existing captions, ensure your environment meets these requirements: - **ffmpeg and ffprobe** must be installed and available in your system PATH for audio extraction. - **API Key Configuration**: Either `GROQ_API_KEY` or `OPENAI_API_KEY` must be set in your environment or stored in `~/.config/watch/.env`. - **Enable Whisper**: Do not pass the `--no-whisper` flag, which disables the fallback and forces frames-only mode. If these conditions are unmet, Claude Video reports that no transcript is available and continues with visual frame analysis only. ## Usage Examples ### Basic Usage (Automatic Fallback) Run the watch command on any URL. The tool attempts caption discovery first, then automatically extracts audio and calls Whisper if needed: ```bash watch https://www.youtube.com/watch?v=example_video ``` ### Force a Specific Backend Override the default Groq preference and use OpenAI's Whisper API explicitly: ```bash watch https://example.com/video.mp4 --whisper openai ``` ### Disable Transcription (Frames-Only Mode) Skip the Whisper fallback entirely when you lack API credentials or only need visual analysis: ```bash watch https://example.com/video.mp4 --no-whisper ``` ### Transcribe a Specific Time Window Limit transcription to a specific segment while still using Whisper if no captions exist: ```bash watch https://example.com/video.mp4 --start 1:30 --end 2:15 ``` ## Summary - **Claude Video transcribes captionless videos** by falling back to Whisper via Groq or OpenAI when `download.fetch_captions()` returns no results. - The fallback triggers automatically in [`watch.py`](https://github.com/bradautomates/claude-video/blob/main/watch.py) when `transcript_segments` is empty and `--no-whisper` is not set. - **Audio extraction** uses `ffmpeg` to create Whisper-compatible 16 kHz mono MP3 files. - **Chunking support** allows transcription of videos larger than 24 MiB by splitting audio automatically. - **Source attribution** clearly labels transcripts as "whisper (groq)" or "whisper (openai)" in the final output. ## Frequently Asked Questions ### What happens if I don't have an API key configured? If neither `GROQ_API_KEY` nor `OPENAI_API_KEY` is found, `whisper.load_api_key()` prompts you to run the setup helper. Without valid credentials, Claude Video skips transcription and operates in frames-only mode. ### Can I choose between Groq and OpenAI for transcription? Yes. While the system prefers Groq by default, you can force a specific backend using the `--whisper` flag followed by either `groq` or `openai` to route requests to your preferred provider. ### Does Claude Video download the entire video to transcribe it? Yes. The tool uses `yt-dlp` via [`download.py`](https://github.com/bradautomates/claude-video/blob/main/download.py) to retrieve the video file, then `ffmpeg` extracts the audio track. For large files, the audio is chunked during the upload phase to stay within API limits. ### What audio format does Claude Video use for Whisper transcription? The system converts video audio to a mono 16 kHz MP3 at approximately 64 kbps using `whisper.extract_audio()`. This format balances quality with file size to ensure compatibility with Whisper's upload requirements while minimizing API costs.