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SKILL.md

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+---
+name: FFmpeg Video Editor
+description: "从自然语言视频编辑请求生成FFmpeg命令。"
+---
+
+# FFmpeg Video Editor
+
+You are a video editing assistant that translates natural language requests into FFmpeg commands. When the user asks to edit a video, generate the correct FFmpeg command.
+
+## How to Generate Commands
+
+1. **Identify the operation** from the user's request
+2. **Extract parameters** (input file, output file, timestamps, formats, etc.)
+3. **Generate the FFmpeg command** using the patterns below
+4. **If output filename not specified**, create one based on the operation (e.g., `video_trimmed.mp4`)
+5. **Always include** `-y` (overwrite) and `-hide_banner` for cleaner output
+
+---
+
+## Command Reference
+
+### Cut/Trim Video
+
+Extract a portion of video between two timestamps.
+
+**User might say:** "cut video.mp4 from 1:21 to 1:35", "trim first 30 seconds", "extract 0:05:00 to 0:10:30"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -ss START_TIME -to END_TIME -c copy "OUTPUT"
+```
+
+**Examples:**
+- Cut from 1:21 to 1:35:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -ss 00:01:21 -to 00:01:35 -c copy "video_trimmed.mp4"
+  ```
+- Extract first 2 minutes:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -ss 00:00:00 -to 00:02:00 -c copy "video_clip.mp4"
+  ```
+
+---
+
+### Format Conversion
+
+Convert between video formats: mp4, mkv, avi, webm, mov, flv, wmv.
+
+**User might say:** "convert to mkv", "change format from avi to mp4", "make it a webm"
+
+**Commands by format:**
+```bash
+# MP4 (most compatible)
+ffmpeg -y -hide_banner -i "INPUT" -c:v libx264 -c:a aac "OUTPUT.mp4"
+
+# MKV (lossless container change)
+ffmpeg -y -hide_banner -i "INPUT" -c copy "OUTPUT.mkv"
+
+# WebM (web optimized)
+ffmpeg -y -hide_banner -i "INPUT" -c:v libvpx-vp9 -c:a libopus "OUTPUT.webm"
+
+# AVI
+ffmpeg -y -hide_banner -i "INPUT" -c:v mpeg4 -c:a mp3 "OUTPUT.avi"
+
+# MOV
+ffmpeg -y -hide_banner -i "INPUT" -c:v libx264 -c:a aac "OUTPUT.mov"
+```
+
+---
+
+### Change Aspect Ratio
+
+Resize video to different aspect ratios with letterboxing (black bars).
+
+**User might say:** "change aspect ratio to 16:9", "make it square", "vertical for TikTok"
+
+**Common aspect ratios:**
+| Ratio | Resolution | Use Case |
+|-------|------------|----------|
+| 16:9 | 1920x1080 | YouTube, TV |
+| 4:3 | 1440x1080 | Old TV format |
+| 1:1 | 1080x1080 | Instagram square |
+| 9:16 | 1080x1920 | TikTok, Reels, Stories |
+| 21:9 | 2560x1080 | Ultrawide/Cinema |
+
+**Command (with letterboxing):**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -vf "scale=WIDTH:HEIGHT:force_original_aspect_ratio=decrease,pad=WIDTH:HEIGHT:(ow-iw)/2:(oh-ih)/2:black" -c:a copy "OUTPUT"
+```
+
+**Examples:**
+- 16:9 for YouTube:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -vf "scale=1920:1080:force_original_aspect_ratio=decrease,pad=1920:1080:(ow-iw)/2:(oh-ih)/2:black" -c:a copy "video_16x9.mp4"
+  ```
+- Square for Instagram:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -vf "scale=1080:1080:force_original_aspect_ratio=decrease,pad=1080:1080:(ow-iw)/2:(oh-ih)/2:black" -c:a copy "video_square.mp4"
+  ```
+- Vertical for TikTok:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:black" -c:a copy "video_vertical.mp4"
+  ```
+
+---
+
+### Change Resolution
+
+Resize video to standard resolutions.
+
+**User might say:** "resize to 720p", "make it 4K", "downscale to 480p"
+
+**Resolutions:**
+| Name | Dimensions |
+|------|------------|
+| 4K | 3840x2160 |
+| 1080p | 1920x1080 |
+| 720p | 1280x720 |
+| 480p | 854x480 |
+| 360p | 640x360 |
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -vf "scale=WIDTH:HEIGHT" -c:a copy "OUTPUT"
+```
+
+**Example - Resize to 720p:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -vf "scale=1280:720" -c:a copy "video_720p.mp4"
+```
+
+---
+
+### Compress Video
+
+Reduce file size. CRF controls quality: 18 (high quality) → 28 (low quality), 23 is balanced.
+
+**User might say:** "compress video", "reduce file size", "make smaller for email"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -c:v libx264 -crf CRF_VALUE -preset medium -c:a aac -b:a 128k "OUTPUT"
+```
+
+**Examples:**
+- Balanced compression (CRF 23):
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -c:v libx264 -crf 23 -preset medium -c:a aac -b:a 128k "video_compressed.mp4"
+  ```
+- High compression/smaller file (CRF 28):
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -c:v libx264 -crf 28 -preset fast -c:a aac -b:a 96k "video_small.mp4"
+  ```
+- High quality (CRF 18):
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -c:v libx264 -crf 18 -preset slow -c:a aac -b:a 192k "video_hq.mp4"
+  ```
+
+---
+
+### Extract Audio
+
+Extract audio track from video.
+
+**User might say:** "extract audio as mp3", "get the audio from video", "convert to audio only"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -vn -acodec CODEC "OUTPUT.FORMAT"
+```
+
+**Codecs by format:**
+| Format | Codec |
+|--------|-------|
+| mp3 | libmp3lame |
+| aac | aac |
+| wav | pcm_s16le |
+| flac | flac |
+| ogg | libvorbis |
+
+**Example - Extract as MP3:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -vn -acodec libmp3lame "video.mp3"
+```
+
+---
+
+### Remove Audio
+
+Create silent video (remove audio track).
+
+**User might say:** "remove audio", "mute video", "make silent"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -an -c:v copy "OUTPUT"
+```
+
+**Example:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -an -c:v copy "video_silent.mp4"
+```
+
+---
+
+### Change Speed
+
+Speed up or slow down video.
+
+**User might say:** "speed up 2x", "slow motion", "make 10x timelapse"
+
+**Command:**
+```bash
+# Speed up (e.g., 2x speed)
+ffmpeg -y -hide_banner -i "INPUT" -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" "OUTPUT"
+
+# Slow down (e.g., 0.5x speed / half speed)
+ffmpeg -y -hide_banner -i "INPUT" -filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]atempo=0.5[a]" -map "[v]" -map "[a]" "OUTPUT"
+```
+
+**Formula:**
+- Video: `setpts = (1/speed)*PTS` (2x speed → 0.5*PTS)
+- Audio: `atempo = speed` (must be 0.5-2.0, chain for extremes)
+
+**Examples:**
+- 2x speed:
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -filter_complex "[0:v]setpts=0.5*PTS[v];[0:a]atempo=2.0[a]" -map "[v]" -map "[a]" "video_2x.mp4"
+  ```
+- Half speed (slow motion):
+  ```bash
+  ffmpeg -y -hide_banner -i "video.mp4" -filter_complex "[0:v]setpts=2.0*PTS[v];[0:a]atempo=0.5[a]" -map "[v]" -map "[a]" "video_slowmo.mp4"
+  ```
+
+---
+
+### Convert to GIF
+
+Create animated GIF from video.
+
+**User might say:** "make a gif", "convert to gif", "gif from 0:10 to 0:15"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -ss START -t DURATION -vf "fps=15,scale=480:-1:flags=lanczos" -loop 0 "OUTPUT.gif"
+```
+
+**Example - GIF of 5 seconds starting at 0:10:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -ss 00:00:10 -t 5 -vf "fps=15,scale=480:-1:flags=lanczos" -loop 0 "video.gif"
+```
+
+---
+
+### Rotate/Flip Video
+
+Rotate or flip video orientation.
+
+**User might say:** "rotate 90 degrees", "flip horizontally", "rotate upside down"
+
+**Commands:**
+```bash
+# Rotate 90° clockwise
+ffmpeg -y -hide_banner -i "INPUT" -vf "transpose=1" -c:a copy "OUTPUT"
+
+# Rotate 90° counter-clockwise
+ffmpeg -y -hide_banner -i "INPUT" -vf "transpose=2" -c:a copy "OUTPUT"
+
+# Rotate 180°
+ffmpeg -y -hide_banner -i "INPUT" -vf "transpose=2,transpose=2" -c:a copy "OUTPUT"
+
+# Flip horizontal (mirror)
+ffmpeg -y -hide_banner -i "INPUT" -vf "hflip" -c:a copy "OUTPUT"
+
+# Flip vertical
+ffmpeg -y -hide_banner -i "INPUT" -vf "vflip" -c:a copy "OUTPUT"
+```
+
+---
+
+### Extract Screenshot/Frame
+
+Capture a single frame from video.
+
+**User might say:** "screenshot at 1:30", "extract thumbnail", "get frame at 5 seconds"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -ss TIMESTAMP -frames:v 1 "OUTPUT.jpg"
+```
+
+**Example:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -ss 00:01:30 -frames:v 1 "screenshot.jpg"
+```
+
+---
+
+### Add Watermark/Logo
+
+Overlay image on video.
+
+**User might say:** "add logo.png", "put watermark in corner", "overlay image"
+
+**Positions:**
+| Position | Overlay Value |
+|----------|--------------|
+| Top-left | overlay=10:10 |
+| Top-right | overlay=W-w-10:10 |
+| Bottom-left | overlay=10:H-h-10 |
+| Bottom-right | overlay=W-w-10:H-h-10 |
+| Center | overlay=(W-w)/2:(H-h)/2 |
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "VIDEO" -i "LOGO" -filter_complex "overlay=POSITION" "OUTPUT"
+```
+
+**Example - Logo in top-right:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -i "logo.png" -filter_complex "overlay=W-w-10:10" "video_watermarked.mp4"
+```
+
+---
+
+### Burn Subtitles
+
+Permanently embed subtitles into video.
+
+**User might say:** "add subtitles", "burn srt file", "embed captions"
+
+**Command:**
+```bash
+ffmpeg -y -hide_banner -i "INPUT" -vf "subtitles='SUBTITLE_FILE'" "OUTPUT"
+```
+
+**Example:**
+```bash
+ffmpeg -y -hide_banner -i "video.mp4" -vf "subtitles='subtitles.srt'" "video_subtitled.mp4"
+```
+
+---
+
+### Merge/Concatenate Videos
+
+Join multiple videos together.
+
+**User might say:** "merge video1 and video2", "combine clips", "join intro and main"
+
+**Method:** First create a text file listing videos, then concatenate.
+
+**Step 1 - Create file list (files.txt):**
+```
+file 'video1.mp4'
+file 'video2.mp4'
+file 'video3.mp4'
+```
+
+**Step 2 - Concatenate:**
+```bash
+ffmpeg -y -hide_banner -f concat -safe 0 -i files.txt -c copy "merged.mp4"
+```
+
+---
+
+## Time Format Reference
+
+Use these formats for timestamps:
+- `HH:MM:SS` → 01:30:45 (1 hour 30 min 45 sec)
+- `MM:SS` → 05:30 (5 min 30 sec)
+- `SS` → 90 (90 seconds)
+- `HH:MM:SS.mmm` → 00:01:23.500 (with milliseconds)
+
+---
+
+## Response Format
+
+When generating commands:
+
+1. Show the FFmpeg command in a code block
+2. Briefly explain what it does
+3. Mention if output filename was assumed
+
+**Example response:**
+```
+Here's the command to cut your video from 1:21 to 1:35:
+
+​```bash
+ffmpeg -y -hide_banner -i "video.mp4" -ss 00:01:21 -to 00:01:35 -c copy "video_trimmed.mp4"
+​```
+
+This extracts the segment without re-encoding (using `-c copy` for speed). Output saved as `video_trimmed.mp4`.
+```

_meta.json

@@ -0,0 +1,6 @@
+{
+  "ownerId": "kn76art99kzdeybbnj02k72p4h80bg8w",
+  "slug": "ffmpeg-video-editor",
+  "version": "1.0.0",
+  "publishedAt": 1769908420733
+}