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Asset Compressor

By Alexis Rios-Negron · Voltkit 0.13.1

Asset Compressor shrinks images and videos and removes the hidden metadata inside them (location, camera, editing history). It never touches your originals: it writes a new file next to each one.

Asset Compressor with four compressed files and their size savings
Asset Compressor with four compressed files and their size savings

Use it#

  1. Open Asset Compressor and drop files on the window, or click Choose Files… and pick them (you can select several).
  2. Each file appears under Results with its progress and, when done, how much smaller it became.
  3. Find the result beside the original, named name.min.ext. A file called photo.jpg produces photo.min.jpg.

You can also drag files from your file manager onto the Drop Files Here area.

Formats#

FormatExtensionsHow it is compressedNeeds
PNG.pngLossless, with every metadata chunk removed. Built into Voltkit.nothing
JPEG.jpg, .jpegMetadata stripped, lossy at the chosen qualityjpegoptim
WebP.webpMetadata removed, lossy at the chosen qualitycwebp (package webp)
MP4 video.mp4, .m4v, .movRe-encoded with H.264 and AAC audio (128 kbps), metadata removed, with the index at the start for fast web playbackffmpeg

In Voltkit's own tests the typical savings were: JPEG −43 %, PNG −23 % (lossless), WebP −60 %, MP4 −77 %. Your results depend on the files.

Compression settings#

Quality goes from 1 (smallest file) to 100 (best quality) and defaults to 80. It controls JPEG, WebP and video. PNG is always lossless, so quality does not apply to it. Change the default for every run in the configuration file:

[compress]
quality = 80

Safety#

  • Originals are never modified or deleted.
  • Metadata is removed from the copy only.
  • If a helper program is missing, the file fails with a message naming it, and the banner at the top of the window and voltkit doctor tell you what to install.

From the terminal#

voltkit compress photo.jpg                 # writes photo.min.jpg
voltkit compress *.png                     # several files
voltkit compress clip.mp4 --quality 70     # smaller video

The command prints each result and the size saved.

Troubleshooting#

  • A format fails. Install its helper: jpegoptim for JPEG, webp for WebP, ffmpeg for MP4. Run voltkit doctor for the command for your distribution.
  • The file did not get smaller. Already-optimized files may not shrink. Lower the quality for lossy formats.