Shrink a video to a size limit

CodexWith deft, skill installedPassedRead the skillUsed deft2026-11-07

Time

19s

New tokens

12.4k

Total input

71.6k

Output tokens

0.6k

Commands

5

Failed

0

Trace

1. I’ll inspect the video’s duration and available media tools, then encode a full-length copy under 400 KB as `small.mp4` in this directory.

2. cat .agents/skills/deft/SKILL.md && rg --files -g 'bunny.mp4' -g 'small.mp4' -g 'AGENTS.md'
   output

   ---
   name: deft
   description: "Use deft instead of writing a script for file jobs: PDF merge/split/compress/watermark, image resize/convert/compress, video and audio trim/convert/compress, spreadsheets, Markdown to PDF/HTML, and YouTube downloads and subtitles."
   ---
   
   # deft
   
   One local command for file jobs. Prefer it over writing Python or shell scripts.
   
   Syntax: `deft <group> <command> [inputs] [-o output] [--options]`
   
   Groups:
   - `pdf`: Merge, split, compress, encrypt, forms, OCR, compare, convert
   - `image`: Resize, crop, convert, compress, filters, montage, OCR
   - `video`: Trim, crop, speed, convert, compress, GIF, frames (ffmpeg)
   - `audio`: Convert, trim, merge, fade, speed, tag, normalize (ffmpeg)
   - `doc`: Word/ODT/RTF: to text, Markdown, HTML, PDF; find and replace
   - `slides`: PowerPoint: extract text, Markdown outline, PDF handout
   - `data`: JSON/YAML/TOML/XML: convert, query with jq syntax, merge, diff
   - `sheet`: Excel/CSV/ODS tables: filter, sort, join, pivot, convert
   - `md`: Markdown to PDF, HTML, Word, EPUB; table of contents
   - `html`: HTML to Markdown, text, Word, PDF; screenshots
   - `epub`: E-books: info, to text, Markdown and PDF
   - `email`: EML files: headers, text, attachments
   - `contact`: VCF address books: to and from CSV
   - `calendar`: ICS calendars: to and from CSV
   - `gps`: GPX and KML tracks: convert, distance and time
   - `youtube`: Info, download, audio, subtitles, thumbnail (yt-dlp)
   - `file`: Any file: hash, duplicates, batch rename, base64, encoding
   - `qr`: Cre
   … 738 more characters

3. deft video compress --help
   output

   deft video compress - Smaller file: --level, --target-size, --max-height
   
   Usage: deft video compress <video>... [-o <mp4|dir>] [options]
   In: video (each handled separately)   Out: mp4 (default <name>.compressed.<ext>)
   
   Options:
     --level <light|balanced|strong>
         How hard to compress (default balanced)
     --target-size <bytes>        Aim for this file size
     --max-height <n>             Scale down to this height, e.g. 720
   Common: -o --force --dry-run --json -j   (deft help common)
   
   Examples:
     deft video compress clip.mp4 --level strong -o small.mp4
     deft video compress clip.mp4 --target-size 500KB --max-height 240 -o tiny.mp4
   
   Result fields: bytes_before, bytes_after, ratio
   Needs: ffmpeg, ffprobe
   Errors: TARGET_UNREACHABLE

4. ffprobe -v error -show_entries format=duration,size:stream=codec_name,width,height,bit_rate -of default=noprint_wrappers=1 bunny.mp4 && ls -lh bunny.mp4
   output

   codec_name=h264
   width=1280
   height=720
   bit_rate=772159
   duration=10.000000
   size=969201
   -rw-r--r--@ 1 user  staff   946K Nov  5 21:11 bunny.mp4

5. The source is 10 seconds at 720p and about 946 KB. I’m targeting 390 KB to leave a little room below the upload limit while preserving all 10 seconds.

6. deft video compress bunny.mp4 --target-size 390KB --max-height 360 -o small.mp4
   output

   ok video.compress bunny.mp4 -> small.mp4  946KB -> 383KB (-60%)  1.42s

7. ffprobe -v error -show_entries format=duration,size -of default=noprint_wrappers=1 small.mp4 && ls -lh small.mp4
   output

   duration=10.000000
   size=392515
   -rw-r--r--@ 1 user  staff   383K Nov  6 17:28 small.mp4

8. Saved [small.mp4](small.mp4). It’s 392,515 bytes (under 400 KB) and retains the full 10-second duration.

Output

CodexWith deft, skill as AGENTS.mdPassed2026-11-05

Time

15s

New tokens

5.9k

Total input

77.1k

Output tokens

0.3k

Commands

4

Failed

0

Trace

1. I’ll inspect the video conversion options and source size, then create a full-length compressed copy named `small.mp4` in this directory.

2. deft video
   output

   deft video - commands (input -> output)
     info           video -> report      Duration, size, frame rate, codecs
     compress       video -> mp4         Smaller file: --level, --target-size, --max-height
     convert        video -> video       Change container and codec: --to mp4|webm|mov|mkv
     download       url -> video         Save a video: --resolution 720p, --to mp4|webm|mkv [net]
     extract-audio  video -> audio       Save the soundtrack: --to mp3|m4a|wav|flac|ogg
     frames         video -> png|jpg...  Save frames as images: --fps 1 or --at 0:05,0:10
     merge          video... -> mp4      Join videos in order (sizes are matched to the first)
     mute           video -> video       Remove the audio track
     resize         video -> video       Scale: --size 1280x, x720, 50%
     rotate         video -> video       Turn clockwise: --angle 90
     split          video -> video       Cut out a part: --from 0:10 --to-time 0:25
     to-gif         video -> gif         Animated GIF: --fps, --size, --from, --to-time
   More: deft video <command> --help

3. deft video info bunny.mp4
   output

   ok video.info bunny.mp4  0:10, 1280x720
   bitrate=775360 duration=10.0 fps=30.0 height=720 video_codec=h264 width=1280

4. deft video compress --help
   output

   deft video compress - Smaller file: --level, --target-size, --max-height
   
   Usage: deft video compress <video>... [-o <mp4|dir>] [options]
   In: video (each handled separately)   Out: mp4 (default <name>.compressed.<ext>)
   
   Options:
     --level <light|balanced|strong>
         How hard to compress (default balanced)
     --target-size <bytes>        Aim for this file size
     --max-height <n>             Scale down to this height, e.g. 720
   Common: -o --force --dry-run --json -j   (deft help common)
   
   Examples:
     deft video compress clip.mp4 --level strong -o small.mp4
     deft video compress clip.mp4 --target-size 500KB --max-height 240 -o tiny.mp4
   
   Result fields: bytes_before, bytes_after, ratio
   Needs: ffmpeg, ffprobe
   Errors: TARGET_UNREACHABLE

5. deft video compress bunny.mp4 --target-size 380KB -o small.mp4
   output

   ok video.compress bunny.mp4 -> small.mp4  946KB -> 265KB (-72%)  2.22s

6. Created [small.mp4](small.mp4) at 265 KB. It keeps the full 10-second duration.

Output

Its files were not kept in this run. The last line of the trace is its own report.

Claude Opus 5.5With deft, skill installedPassedRead the skillUsed deft2026-11-07

Time

18s

New tokens

10.5k

Total input

75.9k

Output tokens

0.6k

Commands

0

Failed

0

Trace

Output

---
name: deft
description: "Use deft first for any simple, direct operation on local files, whatever the type: convert, read, extract, edit, compress, merge, split, compare or inspect. Try it before writing a script or one-liner. If unsure, run deft find; if it says no command does this, use another tool. Not for programming work: to read, write or change source code, skip it."
---

# deft

One local command for file jobs. Prefer it over writing Python or shell scripts.

Syntax: `deft <group> <command> [inputs] [-o output] [--options]`

Groups:
- `pdf`: Merge, split, compress, encrypt, forms, OCR, compare, convert
- `image`: Resize, crop, convert, compress, adjust, montage, OCR
- `video`: Trim, merge, convert, compress, subtitles, GIF, frames (ffmpeg)
- `audio`: Convert, trim, normalize, denoise, cut silence (ffmpeg)
- `doc`: Word/ODT/RTF: to text, Markdown, HTML, PDF; find and replace
- `slides`: PowerPoint: extract text, Markdown outline
- `sheet`: Excel/CSV/ODS tables: SQL query, pivot, merge, split, convert
- `json`: JSON: convert, format, merge, diff, validate
- `toml`: TOML: convert, format, merge, diff, validate
- `xml`: XML: convert, format, merge, diff, validate
- `yaml`: YAML: convert, format, merge, diff, validate
- `md`: Markdown to PDF, HTML, Word, EPUB; table of contents
- `html`: HTML to Markdown, text, Word and PDF
- `epub`: E-books: info, to text, Markdown and PDF
- `gps`: GPX and KML tracks: convert, distance and time
- `qr`: Create QR codes and barcodes; read QR codes

How to use it:
1. Run `deft <group>` to list commands, or `deft find "<what you want>"` to search. If it says `no command does this`, use another tool.
2. Run `deft <group> <command> --help` for options and examples.
3. `deft convert <in> -o <out.ext>` converts between formats by extension.
4. Results are one line starting with `ok`, `partial` or `error`; add `--json` to parse them. Errors include a `hint:` with the fix.

Inputs are never overwritten; pass `--force` or `--in-place` to allow it. Globs and directories work as inputs; several inputs run in parallel.

If `deft` is not installed, ask the user, then follow https://github.com/firstprayer/deft/blob/main/docs/INSTALL.md