Fit into a vertical frame

Put bunny.mp4 into a 1080x1920 vertical frame with black bars, keeping the whole picture. Save it as tall.mp4.

The task

The reference answer shows the job can be done with deft. It is not an agent run.

deft video pad bunny.mp4 --size 1080x1920 -o tall.mp4

Input

bunny.mp4 946.5 KB · h264 1280x720, 10.0s

Reference output

tall.mp4 1.6 MB · h264 1080x1920, 10.0s

How a result is judged (1 check)

media: file = "tall.mp4", width = 1080, height = 1920

Runs

CodexWithout deftPassed2026-11-07

Time: 14s
New tokens: 8.7k
Total input: 58.0k
Output tokens: 0.4k
Commands: 2
Failed: 0

Trace

I’ll inspect the video dimensions, then encode it centered on a 1080×1920 black canvas with aspect ratio preserved.
pwd && rg --files -g 'bunny.mp4' -g 'AGENTS.md' -g '"'!node_modules'"'
output
```
bunny.mp4
```

ffprobe -v error -select_streams v:0 -show_entries stream=width,height -of csv=s=x:p=0 bunny.mp4 && ffmpeg -y -i bunny.mp4 -vf "scale=1080:1920:force_original_aspect_ratio=decrease,pad=1080:1920:(ow-iw)/2:(oh-ih)/2:black" -c:v libx264 -pix_fmt yuv420p -c:a copy tall.mp4

output

1280x720
ffmpeg version 7.1.1 Copyright (c) 2000-2025 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.1.0.2.5)
  configuration: --prefix=/opt/homebrew/Cellar/ffmpeg/7.1.1_1 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags='-Wl,-ld_classic' --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox --enable-neon
  libavutil      59. 39.100 / 59. 39.100
  libavcodec     61. 19.101 / 61. 19.101
  libavformat    61.  7.100 / 61.  7.100
  libavdevice    61.  3.100 / 61.  3.100
  libavfilter    10.  4.100 / 10.  4.100
  libswscale      8.  3.100 /  8.  3.100
  libswresample   5.  3.100 /  5.  3.100
  libpostproc    58.  3.100 / 58.  3.100
Input #0, mov,
… 4470 more characters

The source is 1280×720, so it fits at 1080×608 inside the vertical frame with black space above and below. The encode is finishing now.
Done. [tall.mp4](tall.mp4) is 1080×1920, with the full picture centered and black bars above and below.

Output

tall.mp4 2.2 MB · h264 1080x1920, 10.0s

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

Time: 14s
New tokens: 5.5k
Total input: 72.6k
Output tokens: 0.4k
Commands: 4
Failed: 0

Trace

I’ll check the available media tools and `bunny.mp4`, then create `tall.mp4` in the current directory with the full picture centered in a 1080×1920 frame.

cat .agents/skills/deft/SKILL.md && rg --files -g 'bunny.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
… 740 more characters

deft video

output

deft video - commands (input -> output)
  info               video -> report      Duration, size, frame rate, codecs
  add-audio          video -> video       Replace or mix the soundtrack: --audio song.mp3
  add-subtitles      video -> video       Add subtitles: burned into the picture, or --soft
  chunk              video -> video...    Cut into equal parts: --length 10:00
  compress           video -> mp4         Smaller file: --level, --target-size, --max-height
  convert            video|gif -> video   Change container and codec: --to mp4|webm|mov|mkv
  crop               video -> video       Cut a region: --box or --aspect 1:1
  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
  extract-subtitles  video -> srt|vtt     Save an embedded subtitle track: --to srt|vtt
  fade               video -> video       Fade: --fade-in 1 --fade-out 2
  frames             video -> png|jpg...  Save frames as images: --fps 1 or --at 0:05,0:10
  from-images        image... -> video    Slideshow: --duration, --fps, --audio
  merge              video... -> mp4      Join videos; --transition fades
  mute               video -> video       Remove the audio track
  pad                video -> video       Fit into a frame with bars: --size 1080x1920
  repeat             video -> video       Repeat a video: --count 3 plays it three times
  resize             vid
… 891 more characters

deft video pad --help

output

deft video pad - Fit into a frame with bars: --size 1080x1920

Usage: deft video pad <video>... [-o <video|dir>] [options]
In: video (each handled separately)   Out: video (default <name>.padded.<ext>)
Keeps the whole picture, unlike crop. The picture is scaled to fit.

Options:
  --size <size>                Frame size, e.g. 1080x1920 (required)
  --background <color>         Colour of the bars (default black)
Common: -o --force --dry-run --json -j   (deft help common)

Examples:
  deft video pad clip.mp4 --size 480x640 --background white -o tall.mp4
Needs: ffmpeg, ffprobe

`deft video pad` supports fitting the full picture inside the requested frame with black bars. I’m applying it now.
deft video pad bunny.mp4 --size 1080x1920 -o tall.mp4
output
```
ok video.pad bunny.mp4 -> tall.mp4  1.6MB  1.02s
```
Created [tall.mp4](tall.mp4) as a 1080×1920 video with the full picture and black bars.

Output

tall.mp4 1.6 MB · h264 1080x1920, 10.0s

Claude Opus 5.5Without deftPassed2026-11-07

Time: 18s
New tokens: 9.0k
Total input: 42.3k
Output tokens: 0.6k
Commands: 0
Failed: 0

Trace

Output

tall.mp4 4.7 MB · h264 1080x1920, 10.0s

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

Time: 19s
New tokens: 10.2k
Total input: 74.9k
Output tokens: 0.6k
Commands: 0
Failed: 0

Trace

Output

.claude/skills/deft/SKILL.md 2.1 KB

---
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

tall.mp4 1.6 MB · h264 1080x1920, 10.0s

Claude CodeWithout deftNot run yet

Claude CodeWith deftNot run yet