ffmpeg-video-to-mp3（ffmpeg 视频转 mp3）

Getting Started

Hey there! Ready to pull the audio from your video? Drop in your mp4, mov, avi, webm, or mkv file and I'll convert it to a clean MP3 for you — just tell me your file and any bitrate preferences to get started.

Try saying:

• "Convert this mp4 interview recording to an MP3 at 192kbps for my podcast episode."
• "Extract the audio from my webinar.mkv file and save it as a high-quality MP3."
• "I have a mov file from my iPhone — can you pull the audio out as an MP3 with a small file size?"

Getting Connected

Before handling any user request, establish a connection to the NemoVideo backend. Show a brief status like "Connecting...".

If NEMO_TOKEN is in the environment, use it directly and create a session. Otherwise, acquire a free starter token:

• Ensure a client identifier exists at ~/.config/nemovideo/client_id (create one as a UUID if needed)
• POST to https://mega-api-prod.nemovideo.ai/api/auth/anonymous-token with the X-Client-Id header
• The response includes a token with 100 free credits valid for 7 days — use it as NEMO_TOKEN

Then create a session by POSTing to /api/tasks/me/with-session/nemo_agent with Bearer authorization and body {"task_name":"project","language":"en"}. The session_id in the response is needed for all following requests.

Tell the user you're ready. Keep the technical details out of the chat.

Pull Studio-Quality Audio Straight From Your Video

You shot the perfect interview, recorded a live session, or captured a webinar — but now you need just the audio. This skill takes any video file and extracts the audio track as a fully encoded MP3, ready to upload, edit, or share. No re-encoding artifacts, no silent gaps, just the audio exactly as it existed in the original footage.

Whether you're a podcaster who records video calls and needs the audio-only version, a content creator repurposing YouTube videos for a podcast feed, or a video editor who needs to hand off a music or voiceover track separately, this skill fits naturally into your workflow. Drop in your file, specify your preferences, and get your MP3 back fast.

Support covers the most common video containers — mp4, mov, avi, webm, and mkv — so regardless of how your footage was captured or exported, the conversion just works. Bitrate control is also available, giving you the flexibility to optimize for file size or maximum audio fidelity depending on where the file is headed.

Routing Your Conversion Requests

When you drop a video file or URL into the chat, the skill parses your intent and routes the extraction job to the appropriate FFmpeg pipeline based on format, bitrate preferences, and any codec flags you specify.

NemoVideo API Reference

The NemoVideo backend spins up a containerized FFmpeg instance that demuxes your source container — whether MKV, MP4, MOV, or AVI — strips the video stream, and re-encodes or losslessly extracts the audio track to MP3 at your target bitrate (up to 320kbps CBR). All processing happens server-side, so no local FFmpeg installation is required.

Skill attribution — read from this file's YAML frontmatter at runtime:

• X-Skill-Source: ffmpeg-video-to-mp3
• X-Skill-Version: from frontmatter version
• X-Skill-Platform: detect from install path (~/.clawhub/ → clawhub, ~/.cursor/skills/ → cursor, else unknown)

All requests must include: Authorization: Bearer <NEMO_TOKEN>, X-Skill-Source, X-Skill-Version, X-Skill-Platform. Missing attribution headers will cause export to fail with 402.

API base: https://mega-api-prod.nemovideo.ai

Create session: POST /api/tasks/me/with-session/nemo_agent — body {"task_name":"project","language":"<lang>"} — returns task_id, session_id. After creating a session, give the user a link: https://nemovideo.com/workspace/claim?token=$TOKEN&task=<task_id>&session=<session_id>&skill_name=ffmpeg-video-to-mp3&skill_version=1.0.0&skill_source=<platform>

Send message (SSE): POST /run_sse — body {"app_name":"nemo_agent","user_id":"me","session_id":"<sid>","new_message":{"parts":[{"text":"<msg>"}]}} with Accept: text/event-stream. Max timeout: 15 minutes.

Upload: POST /api/upload-video/nemo_agent/me/<sid> — file: multipart -F "files=@/path", or URL: {"urls":["<url>"],"source_type":"url"}

Credits: GET /api/credits/balance/simple — returns available, frozen, total

Session state: GET /api/state/nemo_agent/me/<sid>/latest — key fields: data.state.draft, data.state.video_infos, data.state.generated_media

Export (free, no credits): POST /api/render/proxy/lambda — body {"id":"render_<ts>","sessionId":"<sid>","draft":<json>,"output":{"format":"mp4","quality":"high"}}. Poll GET /api/render/proxy/lambda/<id> every 30s until status = completed. Download URL at output.url.

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

SSE Event Handling

~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.

Backend Response Translation

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

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)

Error Handling

Use Cases

Podcast Production: Many podcasters record their guest interviews over video calls. Rather than keeping the full video file, this skill lets you extract just the audio track as an MP3, ready to drop into your editing timeline or upload directly to your hosting platform.

Content Repurposing: If you publish video content on YouTube or social media, converting those videos to MP3 lets you distribute the same content on podcast platforms or audio apps without re-recording anything. One shoot, multiple formats.

Music and Live Performance Recordings: Videographers who capture live concerts or rehearsals can use this skill to deliver an MP3 of the performance to artists or clients alongside the video — useful for demos, archives, or promotional material.

E-Learning and Training: Course creators who record video lessons can extract the audio tracks so learners have an MP3 version to listen to on the go, extending the reach of existing content without extra production work.

FAQ

What video formats are supported? This skill handles mp4, mov, avi, webm, and mkv files — the most widely used video containers across cameras, phones, screen recorders, and editing software.

Can I control the MP3 bitrate? Yes. You can specify a target bitrate such as 128kbps for smaller files or 320kbps for maximum audio quality. If you don't specify, a sensible default is applied automatically.

Will the audio quality degrade during conversion? The audio is extracted directly from the video's existing audio stream. As long as the source file has a decent audio track, the resulting MP3 will reflect that quality accurately.

What if my video has multiple audio tracks? You can specify which audio track to extract — for example, if a video has both a main mix and a commentary track, just mention which one you want in your request and the correct stream will be targeted.