Do not use MozJPEG progressive default

radarhere · Dec 31, 2024 · 7733640 · 7733640
1 parent 350febf
commit 7733640
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Showing 2 changed files with 11 additions and 1 deletion.
diff --git a/Tests/test_file_jpeg.py b/Tests/test_file_jpeg.py
@@ -281,7 +281,10 @@ def test_progressive(self) -> None:
         assert not im2.info.get("progressive")
         assert im3.info.get("progressive")
 
-        assert_image_equal(im1, im3)
+        if features.check_feature("mozjpeg"):
+            assert_image_similar(im1, im3, 9.39)
+        else:
+            assert_image_equal(im1, im3)
         assert im1_bytes >= im3_bytes
 
     def test_progressive_large_buffer(self, tmp_path: Path) -> None:

diff --git a/src/libImaging/JpegEncode.c b/src/libImaging/JpegEncode.c
@@ -135,6 +135,13 @@ ImagingJpegEncode(Imaging im, ImagingCodecState state, UINT8 *buf, int bytes) {
             }
 
             /* Compressor configuration */
+#ifdef JPEG_C_PARAM_SUPPORTED
+            // MozJPEG
+            if (!context->progressive) {
+              // Do not use MozJPEG progressive default
+              jpeg_c_set_int_param(&context->cinfo, JINT_COMPRESS_PROFILE, JCP_FASTEST);
+            }
+#endif
             jpeg_set_defaults(&context->cinfo);
 
             /* Prevent RGB -> YCbCr conversion */