Convert and Manipulate AVIF Images with Pillow

This guide demonstrates how Python developers can process, modify, and convert modern AVIF (AV1 Image File Format) files using the Pillow library. You will learn how to enable AVIF compatibility within the Python imaging ecosystem, open and inspect AVIF files, apply standard manipulations such as resizing and rotation, and convert images seamlessly between AVIF, JPEG, and PNG formats.

Enabling AVIF Support

While Pillow provides extensive format support, AVIF encoding and decoding typically rely on libavif or the pillow-heif plugin for full cross-platform compatibility.

Install Pillow and pillow-heif via pip:

pip install Pillow pillow-heif

Before performing any file operations, register the AVIF plugin with Pillow at the start of your script:

from PIL import Image
import pillow_heif

# Register AVIF and HEIF openers with Pillow
pillow_heif.register_avif_opener()

Once registered, standard PIL.Image functions handle AVIF files natively.

Reading and Inspecting AVIF Images

Opening an AVIF file uses the standard Image.open() workflow. You can inspect attributes such as format, dimensions, and color mode directly:

from PIL import Image
import pillow_heif

pillow_heif.register_avif_opener()

with Image.open("example.avif") as img:
    print(f"Format: {img.format}")
    print(f"Size: {img.size}")
    print(f"Mode: {img.mode}")

Manipulating AVIF Images

Once loaded into memory, AVIF images behave like any other Pillow Image object. You can resize, crop, filter, or rotate them:

from PIL import Image, ImageFilter
import pillow_heif

pillow_heif.register_avif_opener()

with Image.open("input.avif") as img:
    # Resize while maintaining aspect ratio
    resized_img = img.resize((800, 600))

    # Rotate 90 degrees counter-clockwise
    rotated_img = resized_img.rotate(90, expand=True)

    # Apply a blur filter
    blurred_img = rotated_img.filter(ImageFilter.GaussianBlur(radius=2))

    # Save the manipulated image back to AVIF
    blurred_img.save("manipulated.avif", "AVIF")

Converting Other Formats to AVIF

AVIF offers significantly higher compression efficiency compared to JPEG and PNG. To convert standard image formats to AVIF, open the source image and save it using the format="AVIF" parameter.

from PIL import Image
import pillow_heif

pillow_heif.register_avif_opener()

# Convert a JPEG or PNG to AVIF
with Image.open("source.png") as img:
    # Convert RGBA to RGB if saving without transparency
    if img.mode in ("RGBA", "P"):
        img = img.convert("RGBA")
    else:
        img = img.convert("RGB")

    img.save(
        "output.avif",
        format="AVIF",
        quality=75,    # Compression quality (0-100)
        speed=6        # CPU effort (0 is slowest/best, 10 is fastest)
    )

Adjusting quality controls the balance between compression and visual fidelity. The speed parameter controls encoding performance, with lower numbers yielding smaller files at the cost of processing time.

Converting AVIF to JPEG or PNG

To convert an AVIF file to another format for legacy browser support:

from PIL import Image
import pillow_heif

pillow_heif.register_avif_opener()

with Image.open("input.avif") as img:
    # Convert to RGB if saving to JPEG (JPEG does not support alpha channels)
    if img.mode in ("RGBA", "LA"):
        rgb_img = img.convert("RGB")
        rgb_img.save("converted.jpg", "JPEG", quality=90)
    else:
        img.save("converted.jpg", "JPEG", quality=90)

    # Convert to PNG (preserves transparency)
    img.save("converted.png", "PNG")