CODEWITHSUNDEEP
imagemagickavif
rubo77
rubo77

Reputation: 20865

Convert png images to lossy avif

I try to compress my ~1MB pngs to get a smaller image.

When I compress my images to jpeg with:

for i in card*.png ; do convert -resize 445x625 -background white -flatten "$i" ../medium/"${i%.*}.jpg" ; done

they end up about 100kb

So I tried

for i in card*.png ; do echo $i; convert -resize 445x625 "$i" ../medium/"${i%.*}.avif" ; done

which results in avif images ~400kb, I guess because they are losslessly compressed.

How do I create lossy compressed avif images? And what would be a useful quality level to get images with the text still clearly readeable?

(I use ImageMagick 6.9.10-23 on Ubuntu)

Upvotes: 2

Views: 7277

Answers (1)

rubo77
rubo77

Reputation: 20865

libheif

You can install

apt install libheif-examples

and then use heif-enc to create heif files with:

for i in card*.png ; do echo $i; heif-enc "$i" -o "${i%.*}.avif" ; done

If you need avif format, you need to compile the latest version of libheif, which has the -A option to create avif files. (There is a section in the README there how to build it on your system. But at least on Ubuntu this is not leading to a running heif-enc)

Better use avifenc:

# Install Homebrew
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"
sudo apt install zsh # needed for this pspecific package install
brew install joedrago/repo/avifenc

Now you have the tool to create avif files with the syntax:

avifenc [options] input.[jpg|jpeg|png|y4m] output.avif

(use avifenc --speed 4 --min 20 --max 22 -j 8 to get a higher compression and use all 8 cores)

Upvotes: 1

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