Free Subtitle Generator For Video

Turn a 3-minute YouTube tutorial video into 1080p captioned video files just by typing what you need. Whether it's adding subtitles to videos automatically o...

Security Scan

The skill's requests and runtime instructions are consistent with a cloud subtitle/rendering service: it only needs a single service token (NEMO_TOKEN) and talks to nemovideo.ai endpoints to upload video, manage sessions, and export rendered files.

Purpose & Capability

Name/description (auto-generate and embed subtitles) align with required credential (NEMO_TOKEN) and the API endpoints in SKILL.md (upload, render, state, credits). No unrelated credentials or binaries are requested.

Instruction Scope

Instructions stay within the rendering/subtitle use case and describe uploading files, SSE-based edits, session creation, and export polling. The skill also instructs automatic anonymous-token acquisition if NEMO_TOKEN is not set and to "store the returned session_id" without specifying secure storage—this is expected for a remote service but is worth noting (where/how the token/session are persisted is unspecified).

Install Mechanism

Instruction-only skill with no install spec and no code files, so nothing is written to disk by an installer. Lowest install risk.

Credentials

Only a single service credential (NEMO_TOKEN) is requested, which is proportionate for a cloud render/subtitle API. The SKILL.md frontmatter references a config path (~/.config/nemovideo/) while the registry metadata listed none — a small metadata inconsistency but not an obvious red flag. The skill will create an anonymous token by POSTing a client UUID to the external API if no NEMO_TOKEN is present; this creates short-lived credentials and sends a UUID to the external service (privacy/telemetry consideration).

Persistence & Privilege

always:false (not force-included) and autonomous invocation is default. The skill asks to store a session_id for the session lifecycle but does not request elevated system privileges, modify other skills, or require persistent installation.

Assessment

This skill appears coherent for a cloud subtitle/renderer: it needs a NEMO_TOKEN (or will obtain a short-lived anonymous token) and communicates with mega-api-prod.nemovideo.ai to upload videos and return rendered files. Before installing or invoking: (1) confirm you trust nemovideo.ai and the listed API host; (2) decide whether you want the agent to auto-generate an anonymous token (this sends a generated client UUID to the service and grants 7-day credits); (3) ask where the agent will store the session_id and token if you care about local persistence—there are no instructions for secure storage in the SKILL.md; (4) avoid pasting sensitive videos or credentials into a skill you don't trust. The metadata contains a minor inconsistency (a config path in the skill frontmatter but not in the registry listing) — you may wish to ask the publisher to clarify storage behavior.

Getting Started

Ready when you are. Drop your video files here or describe what you want to make.

Try saying:

• "generate a 3-minute YouTube tutorial video into a 1080p MP4"
• "generate subtitles in English and add them to my video"
• "adding subtitles to videos automatically for YouTubers, content creators, students"

First-Time Connection

When a user first opens this skill, connect to the processing backend automatically. Briefly let them know (e.g. "Setting up...").

Authentication: Check if NEMO_TOKEN is set in the environment. If it is, skip to step 2.

1. Obtain a free token: Generate a random UUID as client identifier. POST to https://mega-api-prod.nemovideo.ai/api/auth/anonymous-token with header X-Client-Id set to that UUID. The response data.token is your NEMO_TOKEN — 100 free credits, valid 7 days.
2. Create a session: POST to https://mega-api-prod.nemovideo.ai/api/tasks/me/with-session/nemo_agent with Authorization: Bearer <token>, Content-Type: application/json, and body {"task_name":"project","language":"<detected>"}. Store the returned session_id for all subsequent requests.

Keep setup communication brief. Don't display raw API responses or token values to the user.

Free Subtitle Generator for Video — Auto-Generate and Embed Video Captions

Send me your video files and describe the result you want. The AI subtitle generation runs on remote GPU nodes — nothing to install on your machine.

A quick example: upload a 3-minute YouTube tutorial video, type "generate subtitles in English and add them to my video", and you'll get a 1080p MP4 back in roughly 30-60 seconds. All rendering happens server-side.

Worth noting: shorter clips under 5 minutes produce the most accurate subtitle sync.

Matching Input to Actions

User prompts referencing free subtitle generator for video, aspect ratio, text overlays, or audio tracks get routed to the corresponding action via keyword and intent classification.

User says...	Action	Skip SSE?
"export" / "导出" / "download" / "send me the video"	→ §3.5 Export	✅
"credits" / "积分" / "balance" / "余额"	→ §3.3 Credits	✅
"status" / "状态" / "show tracks"	→ §3.4 State	✅
"upload" / "上传" / user sends file	→ §3.2 Upload	✅
Everything else (generate, edit, add BGM…)	→ §3.1 SSE	❌

Cloud Render Pipeline Details

Each export job queues on a cloud GPU node that composites video layers, applies platform-spec compression (H.264, up to 1080x1920), and returns a download URL within 30-90 seconds. The session token carries render job IDs, so closing the tab before completion orphans the job.

All calls go to https://mega-api-prod.nemovideo.ai. The main endpoints:

1. Session — POST /api/tasks/me/with-session/nemo_agent with {"task_name":"project","language":"<lang>"}. Gives you a session_id.
2. Chat (SSE) — POST /run_sse with session_id and your message in new_message.parts[0].text. Set Accept: text/event-stream. Up to 15 min.
3. Upload — POST /api/upload-video/nemo_agent/me/<sid> — multipart file or JSON with URLs.
4. Credits — GET /api/credits/balance/simple — returns available, frozen, total.
5. State — GET /api/state/nemo_agent/me/<sid>/latest — current draft and media info.
6. Export — POST /api/render/proxy/lambda with render ID and draft JSON. Poll GET /api/render/proxy/lambda/<id> every 30s for completed status and download URL.

Formats: mp4, mov, avi, webm, mkv, jpg, png, gif, webp, mp3, wav, m4a, aac.

Headers are derived from this file's YAML frontmatter. X-Skill-Source is free-subtitle-generator-for-video, X-Skill-Version comes from the version field, and X-Skill-Platform is detected from the install path (~/.clawhub/ = clawhub, ~/.cursor/skills/ = cursor, otherwise unknown).

Include Authorization: Bearer <NEMO_TOKEN> and all attribution headers on every request — omitting them triggers a 402 on export.

Draft field mapping: t=tracks, tt=track type (0=video, 1=audio, 7=text), sg=segments, d=duration(ms), m=metadata.

Timeline (3 tracks): 1. Video: city timelapse (0-10s) 2. BGM: Lo-fi (0-10s, 35%) 3. Title: "Urban Dreams" (0-3s)

Backend Response Translation

The backend assumes a GUI exists. Translate these into API actions:

Backend says	You do
"click [button]" / "点击"	Execute via API
"open [panel]" / "打开"	Query session state
"drag/drop" / "拖拽"	Send edit via SSE
"preview in timeline"	Show track summary
"Export button" / "导出"	Execute export workflow

SSE Event Handling

Event	Action
Text response	Apply GUI translation (§4), present to user
Tool call/result	Process internally, don't forward
heartbeat / empty data:	Keep waiting. Every 2 min: "⏳ Still working..."
Stream closes	Process final response

~30% of editing operations return no text in the SSE stream. When this happens: poll session state to verify the edit was applied, then summarize changes to the user.

Error Codes

• 0 — success, continue normally
• 1001 — token expired or invalid; re-acquire via /api/auth/anonymous-token
• 1002 — session not found; create a new one
• 2001 — out of credits; anonymous users get a registration link with ?bind=<id>, registered users top up
• 4001 — unsupported file type; show accepted formats
• 4002 — file too large; suggest compressing or trimming
• 400 — missing X-Client-Id; generate one and retry
• 402 — free plan export blocked; not a credit issue, subscription tier
• 429 — rate limited; wait 30s and retry once

Tips and Tricks

The backend processes faster when you're specific. Instead of "make it look better", try "generate subtitles in English and add them to my video" — concrete instructions get better results.

Max file size is 500MB. Stick to MP4, MOV, AVI, WebM for the smoothest experience.

Export as MP4 for widest compatibility across platforms and devices.

Common Workflows

Quick edit: Upload → "generate subtitles in English and add them to my video" → Download MP4. Takes 30-60 seconds for a 30-second clip.

Batch style: Upload multiple files in one session. Process them one by one with different instructions. Each gets its own render.

Iterative: Start with a rough cut, preview the result, then refine. The session keeps your timeline state so you can keep tweaking.