feat: Use new libavif quality and qualityAlpha encoder options

These replace the (now deprecated) qmin and qmax options

src/pillow_avif/AvifImagePlugin.py

@@ -123,23 +123,12 @@ def _save(im, fp, filename, save_all=False):
 
     is_single_frame = total == 1
 
-    qmin = info.get("qmin")
-    qmax = info.get("qmax")
-
-    if qmin is None and qmax is None:
-        # The min and max quantizer settings in libavif range from 0 (best quality)
-        # to 63 (worst quality). If neither are explicitly specified, we use a 0-100
-        # quality scale (default 75) and calculate the qmin and qmax from that.
-        #
-        # - qmin is 0 for quality >= 64. Below that, qmin has an inverse linear
-        #   relation to quality (i.e., quality 63 = qmin 1, quality 0 => qmin 63)
-        # - qmax is 0 for quality=100, then qmax increases linearly relative to
-        #   quality decreasing, until it flattens out at quality=37.
-        quality = info.get("quality", 75)
-        if not isinstance(quality, int):
-            raise ValueError("Invalid quality setting")
-        qmin = max(0, min(64 - quality, 63))
-        qmax = max(0, min(100 - quality, 63))
+    quality = info.get("quality", 75)
+    if not isinstance(quality, int) or quality < 0 or quality > 100:
+        raise ValueError("Invalid quality setting")
+    quality_alpha = info.get("quality_alpha", 100)
+    if not isinstance(quality_alpha, int) or quality_alpha < 0 or quality_alpha > 100:
+        raise ValueError("Invalid quality_alpha setting")
 
     duration = info.get("duration", 0)
     subsampling = info.get("subsampling", "4:2:0")
@@ -184,8 +173,8 @@ def _save(im, fp, filename, save_all=False):
         im.size[0],
         im.size[1],
         subsampling,
-        qmin,
-        qmax,
+        quality,
+        quality_alpha,
         speed,
         codec,
         range_,

src/pillow_avif/_avif.c

@@ -11,8 +11,8 @@
 
 typedef struct {
     avifPixelFormat subsampling;
-    int qmin;
-    int qmax;
+    int quality;
+    int quality_alpha;
     int speed;
     avifCodecChoice codec;
     avifRange range;
@@ -203,8 +203,8 @@ AvifEncoderNew(PyObject *self_, PyObject *args) {
     avifEncoder *encoder = NULL;
 
     char *subsampling = "4:2:0";
-    int qmin = AVIF_QUANTIZER_BEST_QUALITY;  // =0
-    int qmax = 10;                           // "High Quality", but not lossless
+    int quality = 75;
+    int quality_alpha = 100;
     int speed = 8;
     PyObject *icc_bytes;
     PyObject *exif_bytes;
@@ -225,8 +225,8 @@ AvifEncoderNew(PyObject *self_, PyObject *args) {
             &width,
             &height,
             &subsampling,
-            &qmin,
-            &qmax,
+            &quality,
+            &quality_alpha,
             &speed,
             &codec,
             &range,
@@ -254,8 +254,8 @@ AvifEncoderNew(PyObject *self_, PyObject *args) {
         return NULL;
     }
 
-    enc_options.qmin = normalize_quantize_value(qmin);
-    enc_options.qmax = normalize_quantize_value(qmax);
+    enc_options.quality = quality;
+    enc_options.quality_alpha = quality_alpha;
 
     if (speed < AVIF_SPEED_SLOWEST) {
         speed = AVIF_SPEED_SLOWEST;
@@ -321,8 +321,8 @@ AvifEncoderNew(PyObject *self_, PyObject *args) {
         }
 
         encoder->maxThreads = max_threads;
-        encoder->minQuantizer = enc_options.qmin;
-        encoder->maxQuantizer = enc_options.qmax;
+        encoder->quality = enc_options.quality;
+        encoder->qualityAlpha = enc_options.quality_alpha;
         encoder->codecChoice = enc_options.codec;
         encoder->speed = enc_options.speed;
         encoder->timescale = (uint64_t)1000;

tests/test_file_avif.py

@@ -494,27 +494,6 @@ def test_encoder_codec_available_cannot_decode(self):
     def test_encoder_codec_available_invalid(self):
         assert _avif.encoder_codec_available("foo") is False
 
-    @pytest.mark.parametrize(
-        "quality,expected_qminmax",
-        [
-            [0, (63, 63)],
-            [100, (0, 0)],
-            [90, (0, 10)],
-            [None, (0, 25)],  # default
-            [50, (14, 50)],
-        ],
-    )
-    def test_encoder_quality_qmin_qmax_map(self, tmp_path, quality, expected_qminmax):
-        MockEncoder = mock.Mock(wraps=_avif.AvifEncoder)
-        with mock.patch.object(_avif, "AvifEncoder", new=MockEncoder) as mock_encoder:
-            with Image.open("tests/images/hopper.avif") as im:
-                test_file = str(tmp_path / "temp.avif")
-                if quality is None:
-                    im.save(test_file)
-                else:
-                    im.save(test_file, quality=quality)
-            assert mock_encoder.call_args[0][3:5] == expected_qminmax
-
     def test_encoder_quality_valueerror(self, tmp_path):
         with Image.open("tests/images/hopper.avif") as im:
             test_file = str(tmp_path / "temp.avif")