# Ffmpeg

> Use when the user asks for FFmpeg or FFprobe commands, video/audio conversion, trimming, resizing, padding, overlays, subtitles, thumbnails, GIFs, storyboards, slideshows, speed control, audio mixing, jump cuts, social-media crops, hardware-accelerated encoding, codec settings, CRF/preset tuning, stream mapping, or troubleshooting media automation pipelines.

- Skill: `javimosch/ffmpeg` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add javimosch/ffmpeg`
- Raw SKILL.md: https://api.skillmd.com/api/skills/javimosch/ffmpeg/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: javimosch (https://skillmd.com/u/javimosch)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/javimosch/ffmpeg

---


# FFmpeg Plugin

Use this skill to produce reliable, explainable FFmpeg/FFprobe commands for media automation via supercli.

## Commands

All commands use `supercli ffmpeg <resource> <action>` syntax.

### Video Operations

| Command | Description |
|---------|-------------|
| `ffmpeg video convert` | Convert between formats (mp4, mkv, avi, webm, mov) |
| `ffmpeg video resize` | Scale to specific dimensions |
| `ffmpeg video trim` | Cut time range (lossless with `-c copy`) |
| `ffmpeg video thumbnail` | Extract a single frame as image |
| `ffmpeg video gif` | Create animated GIF |
| `ffmpeg video concat` | Join multiple videos |
| `ffmpeg video speed` | Change playback speed (slow-mo / fast-forward) |
| `ffmpeg video jump-cut` | Remove selected time ranges (jump cuts) |
| `ffmpeg video overlay` | Overlay logo/image with position and timing |
| `ffmpeg video subtitle` | Burn subtitles into video (ASS/SRT) |
| `ffmpeg video slideshow` | Create video slideshow from images with audio |
| `ffmpeg video hw-encode` | Hardware-accelerated encoding (NVENC/QSV) |

### Audio Operations

| Command | Description |
|---------|-------------|
| `ffmpeg audio extract` | Extract audio track from video |
| `ffmpeg audio mix` | Mix background music under original audio |

### Media Inspection

| Command | Description |
|---------|-------------|
| `ffmpeg media inspect` | Get detailed metadata as JSON |
| `ffmpeg media storyboard` | Generate storyboard thumbnails from scene changes |

## Defaults

- Web-compatible MP4: `-c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a aac -movflags +faststart`
- High-quality archival H.264: `-c:v libx264 -crf 17` or `-crf 18`
- Smaller modern MP4: `-c:v libx265 -crf 24 -vtag hvc1 -c:a aac`
- WebM/VP9: `-c:v libvpx-vp9 -crf 15 -b:v 0 -c:a libopus`
- Preserve audio when safe: `-c:a copy`
- Force square pixels after scale/pad/crop: `setsar=1:1`
- Playback compatibility from generated images: `format=yuv420p` or `-pix_fmt yuv420p`

## Common Command Patterns

### Inspect media

```bash
ffprobe -hide_banner -show_streams -show_format input.mp4
```

### Remux without re-encoding

```bash
ffmpeg -i input.mp4 -c copy output.mkv
```

### Resize and pad to vertical 1080x1920

```bash
ffmpeg -i input.mp4 \
  -vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:color=black,setsar=1:1" \
  -c:v libx264 -crf 18 -preset slow -pix_fmt yuv420p -c:a aac -movflags +faststart \
  output.mp4
```

### Frame-accurate trim

Use output seeking and re-encode for reliable exact cuts:

```bash
ffmpeg -i input.mp4 -ss 00:00:10 -to 00:00:25 \
  -c:v libx264 -crf 18 -preset slow -c:a aac output_trimmed.mp4
```

Use input seeking before `-i` only when speed matters more than accuracy.

### Replace audio

```bash
ffmpeg -i input.mp4 -i music.mp3 \
  -map 0:v -map 1:a -shortest -c:v copy -c:a aac output.mp4
```

### Mix background music under original audio

```bash
ffmpeg -i input.mp4 -i music.mp3 \
  -filter_complex "[1:a]volume=0.2[bgm];[0:a][bgm]amix=inputs=2:duration=shortest[a]" \
  -map 0:v -map "[a]" -c:v copy -c:a aac -shortest output.mp4
```

### Overlay logo for a time range

```bash
ffmpeg -i input.mp4 -i logo.png \
  -filter_complex "overlay=x=(main_w-overlay_w)/8:y=(main_h-overlay_h)/8:enable='gte(t,1)*lte(t,7)'" \
  -c:v libx264 -crf 18 -preset slow -c:a copy output.mp4
```

### Burn subtitles

```bash
ffmpeg -i input.mp4 \
  -vf "subtitles=subtitles.srt:fontsdir=.:force_style='FontName=Poppins,FontSize=24,PrimaryColour=&HFFFFFF'" \
  -c:v libx264 -crf 18 -preset slow -c:a copy output_subtitled.mp4
```

### Add soft subtitle track

```bash
ffmpeg -i input.mp4 -i subtitles.srt \
  -c copy -c:s srt -disposition:s:0 default output.mkv
```

### Thumbnail

```bash
ffmpeg -i input.mp4 -ss 00:00:07 -frames:v 1 -q:v 2 thumbnail.jpg
```

### GIF from video

```bash
ffmpeg -i input.mp4 \
  -vf "select='gt(trunc(t/2),trunc(prev_t/2))',setpts='PTS*0.1',scale=trunc(oh*a/2)*2:320:force_original_aspect_ratio=decrease,pad=trunc(oh*a/2)*2:320:-1:-1" \
  -loop 0 -an output.gif
```

Takes every second frame and accelerates playback 10x. Use `-loop 1` for play-once.

### Hardware acceleration (Nvidia NVENC)

```bash
ffmpeg -i input.avi -c:v h264_nvenc output.mp4
ffmpeg -i input.avi -c:v hevc_nvenc output.mp4
```

### Hardware acceleration (Intel QSV)

```bash
ffmpeg -init_hw_device qsv=hw -filter_hw_device hw -i input.avi -c:v h264_qsv output.mp4
```

### Scene-change thumbnail

```bash
ffmpeg -i input.mp4 -vf "select='gt(scene,0.4)'" -frames:v 1 -q:v 2 thumbnail_scene.jpg
```

### Storyboard tile from scene changes

```bash
ffmpeg -i input.mp4 -vf "select='gt(scene,0.4)',scale=640:480,tile=2x2" -frames:v 1 storyboard.jpg
```

## Gotchas

- `-c copy` cannot apply filters and is not frame-accurate for most cuts.
- `-ss` before `-i` is fast but approximate; `-ss` after `-i` is slower but accurate.
- MP4 playback in QuickTime and browsers often needs `yuv420p` for H.264 output.
- Use `-movflags +faststart` for web-hosted MP4/MOV/M4A so playback starts sooner.
- In filter graphs, `[0:v]` means first input's video stream, `[1:a]` means second input's audio stream, and `-map` chooses which streams become outputs.
- Escaping filter expressions is shell-sensitive. Prefer single quotes inside double-quoted filter graphs for time expressions, and escape commas inside nested expressions when required.
- `drawtext` with special characters is fragile; prefer `textfile=` for user-supplied text.
- Burned subtitles require re-encoding; soft subtitle tracks can often use stream copy.
- Videos without audio will cause `audio extract` and `audio mix` to fail.
- Concat requires identical codecs/resolutions for lossless operation.
- All plugin commands use `-y` flag — outputs are overwritten without prompting.