How to specify the "speed" parameter

[MimoKar]

Describe the bug

Parameter speed is ignored during image encoding. Doesn't matter what value is set, it is using some default.

Steps/Code to Reproduce

im.save(new_file,format='AVIF', quality=quality, alpha_quality=quality, speed=0)

Expected Results

Speed of encoding will differ for different setting.

Actual Results

Encoding speed is same.

Versions

3.12.5 (tags/v3.12.5:ff3bc82, Aug  6 2024, 20:45:27) [MSC v.1940 64 bit (AMD64)]
Windows-11-10.0.27695-SP0
0.18.0
{'libheif': '1.18.1', 'HEIF': 'x265 HEVC encoder (3.5+1-f0c1022b6)', 'AVIF': 'AOMedia Project AV1 Encoder v3.9.1', 'encoders': {'x265': 'x265 HEVC encoder (3.5+1-f0c1022b6)', 'aom': 'AOMedia Project AV1 Encoder v3.9.1', 'mask': 'mask'}, 'decoders': {'libde265': 'libde265 HEVC decoder, version 1.0.15', 'aom': 'AOMedia Project AV1 Decoder v3.9.1'}}

[bigcat88]

Specifying speed parameter directly to save is not supported.

You can pass custom encoding parameters (i.e. speed) using enc_params kwarg during save

Here is a test for that:

pillow_heif/tests/write_test.py

Lines 186 to 193 in dc33d11

	def test_encoder_parameters():
	out_buf1 = BytesIO()
	out_buf2 = BytesIO()
	heif_buf = helpers.create_heif()
	im_heif = pillow_heif.open_heif(heif_buf)
	im_heif.save(out_buf1, enc_params={"x265:ctu": "32", "x265:min-cu-size": "16", "x265:rdLevel": "2"})
	im_heif.save(out_buf2, enc_params={"x265:ctu": 64, "x265:min-cu-size": 8, "x265:rdLevel": 6})
	assert out_buf1.seek(0, SEEK_END) != out_buf2.seek(0, SEEK_END)

You can check which parameters are supported by which encoder in the libeheif repository or in the encoder repository itself.

[bigcat88]

heif-enc -A --params     
Parameters for encoder `AOMedia Project AV1 Encoder 3.9.1`:
  realtime, default=false
  speed, default=6, [0;9]
  threads, default=12, [1;64]
  quality, default=50, [0;100]
  lossless, default=false
  chroma, default=420, { 420,422,444 }
  tune, default=ssim, { psnr,ssim }
  min-q, default=0, [0;63]
  max-q, default=63, [0;63]
  alpha-quality, [0;100]
  alpha-min-q, [0;63]
  alpha-max-q, [0;63]
  lossless-alpha, default=false

  Image.open("arrow.jpg").save("arrow1.avif", enc_params={"speed": 6})
  Image.open("arrow.jpg").save("arrow2.avif", enc_params={"speed": 1})
  Image.open("arrow.jpg").save("arrow3.avif", enc_params={"speed": 9})

[MimoKar]

alpha_quality is supported in save or via enc_params only?

And is auto tiling available/enabled ?

[bigcat88]

I am not sure about alpha quality parameter..

"tiling" currently is not supported, API for it was introduced only in latest libheif(1.18) that was published not so long ago.

If no one will make a PR to add "tiling support", I will do it myself at the end of autumn, most likely for the New Year.