Options

pillow_heif.options.DECODE_THREADS = 4

Maximum number of threads to use for decoding images(when it is possible)

When use pillow_heif as a plugin you can set it with: register_*_opener(decode_threads=8)

pillow_heif.options.THUMBNAILS = True

Option to enable/disable thumbnail support

When use pillow_heif as a plugin you can set it with: register_*_opener(thumbnails=False)

pillow_heif.options.DEPTH_IMAGES = True

Option to enable/disable depth image support

When use pillow_heif as a plugin you can set it with: register_*_opener(depth_images=False)

pillow_heif.options.QUALITY = None

Default encoding quality

Note

Quality specified during calling save has higher priority then this.

Possible values: None, -1, range(0-100). Set -1 for lossless quality or from 0 to 100, where 0 is lowest and 100 is highest.

Note

Also for lossless encoding you should specify chroma=444 during save.

When use pillow_heif as a plugin you can set it with: register_*_opener(quality=-1)

pillow_heif.options.SAVE_HDR_TO_12_BIT = False

Should 16 bit images be saved to 12 bit instead of 10 bit``

When use pillow_heif as a plugin you can set it with: register_*_opener(save_to_12bit=True)

pillow_heif.options.ALLOW_INCORRECT_HEADERS = False

Can or not the size of image in header differ from decoded one.

Note

If enabled, Image.size can change after loading for images where it is invalid in header.

To learn more read: here

When use pillow_heif as a plugin you can set it with: register_*_opener(allow_incorrect_headers=True)

pillow_heif.options.SAVE_NCLX_PROFILE = True

Should be nclx profile saved or not.

Default for all previous versions(pillow_heif<0.14.0) was NOT TO save nclx profile, due to an old bug in Apple software refusing to open images with nclx profiles. Apple has already fixed this and there is no longer a need to not save the default profile.

Note

save_nclx_profile specified during calling save has higher priority than this.

When use pillow_heif as a plugin you can unset it with: register_*_opener(save_nclx_profile=False)

pillow_heif.options.PREFERRED_ENCODER = {'AVIF': '', 'HEIF': ''}

Use the specified encoder for format.

You can get the available encoders IDs using libheif_info() function.

When use pillow_heif as a plugin you can set this option with preferred_encoder key.

Note

If the specified encoder is missing, the option will be ignored.

pillow_heif.options.PREFERRED_DECODER = {'AVIF': '', 'HEIF': ''}

Use the specified decoder for format.

You can get the available decoders IDs using libheif_info() function.

When use pillow_heif as a plugin you can set this option with preferred_decoder key.

Note

If the specified decoder is missing, the option will be ignored.

Example of use

import pillow_heif

pillow_heif.options.THUMBNAILS = False
pillow_heif.options.DECODE_THREADS = 1

Overriding multiple options at once

When registering a Pillow plugin with pillow_heif.register_heif_opener() or pillow_heif.register_avif_opener()

register_heif_opener(thumbnails=False, quality=100, decode_threads=10)