AI Subtitles (ASR)
When a YouTube video has no captions — or the video is deleted and YouTube's caption endpoint no longer returns them — Tube Search can generate subtitles directly from the audio using a Whisper-class speech-recognition model. The result is a regular SRT/VTT transcript that works in the same places as archived captions: video rows, the /api/subtitles endpoint, and AI summary generation.
What AI Subtitles Do
- Extract audio — from the Wayback Machine archive copy for deleted videos, or directly from the live source for current videos
- Transcribe — a self-hosted ASR model turns the audio into timestamped captions
- Detect language — the model identifies the spoken language automatically
- Output SRT + VTT — the generated files live alongside any archived captions. AI-generated tracks are marked distinctly from archived ones so you always know the source.
Who Can Generate AI Subtitles
| Feature | Anonymous | Registered | Plus | MCP + API |
|---|---|---|---|---|
| View / download existing AI subtitles | Yes | Yes | Yes | Yes |
| Trigger AI subtitle generation | — | — | — | Per-tier quota |
Lower tiers see a faded "Create AI Subtitles" upsell button — but only on deleted videos that have no subtitles available at all (neither archived nor AI-generated). The upsell links to the Pricing page. Per-tier daily quotas are listed there and on your Profile → Plan & Usage tab.
How to Trigger
1
Find a video without archived captions
Search by channel, URL, or text. Videos without an archived "Subtitles" link are candidates for ASR — if the video has audio somewhere (Wayback archive for deleted, or YouTube itself for live), AI subtitles can fill the gap.
2
Click "Create AI Subtitles"
The Create AI Subtitles button appears on every eligible video row. Click it to queue generation. Progress is streamed to the row in real time.
3
Download or read
Once complete, the row flips to a normal Subtitles link. Download as SRT/VTT, paste into a player, or feed the transcript to the AI Summary generator.
AI subtitles count toward the same subtitle-availability flags used elsewhere. If a video had no captions before but now has AI subtitles, it will appear under the "Has Subtitles" filter and become eligible for summary generation.
Which Videos Qualify
- Deleted videos — require an audio copy in the Wayback Machine archive. Most popular videos do; long-tail content often does not.
- Live videos — audio is fetched on demand, so almost any public live video qualifies.
- Age-restricted / private / region-blocked — currently skipped: not reliably reachable, and the Wayback archive rarely has a complete audio track for them.
Limitations
- Audio quality — low-bitrate archive copies, heavy music, or crosstalk degrade recognition. Archived Wayback audio is particularly noisy.
- Language detection — rare languages or heavily-accented speech may be misidentified. The detected language is shown on the transcript page.
- Latency — generation takes from a minute up to several minutes depending on video length. The row stays responsive while work runs in the background.
- Accuracy — ASR is not human-perfect. Proper names, technical jargon, and brand spellings may need manual correction before archival use.
Learn More
Archived Subtitles
How Tube Search recovers original YouTube captions from web archives.
AI Summaries
Once you have a transcript — archived or AI — generate a TL;DR, key points, and tags.
AI Stenograms
L3+ private full-text dialogue transcripts with speaker tags.
Pricing & Quotas
Daily AI subtitle generation limits by tier.