【Mac】コマンドでAVIFをPNGなどに変換する方法

libavifをインストール

Homebrewを使用してlibavifをインストールします。

brew install libavif

avifdecコマンドを使用して画像を変換

avifdec input.png output.avif

avifdecコマンドで使用できるオプションの詳細は以下のとおりです。

$ avifdec --help
Syntax: avifdec [options] input.avif output.[jpg|jpeg|png|y4m]
        avifdec --info    input.avif
Options:
    -h,--help         : Show syntax help
    -V,--version      : Show the version number
    -j,--jobs J       : Number of jobs (worker threads). Use "all" to potentially use as many cores as possible (default: all)
    -c,--codec C      : Codec to use (choose from versions list below)
    -d,--depth D      : Output depth [8,16]. (PNG only; For y4m, depth is retained, and JPEG is always 8bpc)
    -q,--quality Q    : Output quality [0-100]. (JPEG only, default: 90)
    --png-compress L  : Set PNG compression level (PNG only; 0-9, 0=none, 9=max). Defaults to libpng's builtin default.
    -u,--upsampling U : Chroma upsampling (for 420/422). automatic (default), fastest, best, nearest, or bilinear
    -r,--raw-color    : Output raw RGB values instead of multiplying by alpha when saving to opaque formats
                        (JPEG only; not applicable to y4m)
    --index I         : When decoding an image sequence or progressive image, specify which frame index to decode (Default: 0)
    --progressive     : Enable progressive AVIF processing. If a progressive image is encountered and --progressive is passed,
                        avifdec will use --index to choose which layer to decode (in progressive order).
    --no-strict       : Disable strict decoding, which disables strict validation checks and errors
    -i,--info         : Decode all frames and display all image information instead of saving to disk
    --icc FILENAME    : Provide an ICC profile payload (implies --ignore-icc)
    --ignore-icc      : If the input file contains an embedded ICC profile, ignore it (no-op if absent)
    --size-limit C    : Specifies the image size limit (in total pixels) that should be tolerated.
                        Default: 268435456, set to a smaller value to further restrict.
  --dimension-limit C : Specifies the image dimension limit (width or height) that should be tolerated.
                        Default: 32768, set to 0 to ignore.
    --                : Signals the end of options. Everything after this is interpreted as file names.

Version: 1.1.1 (aom [enc/dec]:3.10.0)
libyuv : unavailable