use over 61 workers

.specstory/history/2025-12-23_23-54Z-untitled.md

@@ -0,0 +1,40 @@
+<!-- Generated by SpecStory, Markdown v2.1.0 -->
+
+<!-- cursor Session c6b9ac3c-667a-4529-8923-79fe43eb7838 (2025-12-23 23:54Z) -->
+
+# Untitled (2025-12-23 23:54Z)
+
+_**User (2025-12-23 23:54Z)**_
+
+it didn't work on the threadripper. additional context: @.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md 
+
+Mode: Auto-detect bit depth (preserve 16-bit if present)
+Input directory: input
+Output directory: output
+Scanning for image files...
+Found 646 JPG/JPEG files - ignoring (skipping)
+Found 6371 PNG files to process.
+Corrupted files will be moved to: corrupted
+Using 64 worker processes for compression...
+--------------------------------------------------------------------------------
+Traceback (most recent call last):
+  File "E:\SequenceCompressor\compress_pngs.py", line 427, in <module>
+    main()
+    ~~~~^^
+  File "E:\SequenceCompressor\compress_pngs.py", line 328, in main
+    with ProcessPoolExecutor(max_workers=max_workers) as executor:
+         ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^
+  File "C:\Python314\Lib\concurrent\futures\process.py", line 671, in __init__
+    raise ValueError(
+        f"max_workers must be <= {_MAX_WINDOWS_WORKERS}")
+ValueError: max_workers must be <= 61
+Press any key to continue . . .
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+

compress_pngs.py

@@ -7,12 +7,21 @@ Compresses all PNG files in subdirectories with maximum parallelism.
 import os
 import sys
 import argparse
+import platform
 from pathlib import Path
 from concurrent.futures import ProcessPoolExecutor, as_completed
 from PIL import Image
 import multiprocessing
 import time
 
+# Try to unlock ProcessPoolExecutor on Windows to bypass 61-worker limit
+try:
+    import unlock_processpool
+    unlock_processpool.please()
+    UNLOCKED = True
+except ImportError:
+    UNLOCKED = False
+
 def compress_png(input_path, output_path, force_bitdepth=None):
     """Compress a single PNG file.
     
@@ -311,7 +320,17 @@ def main():
     print(f"Corrupted files will be moved to: {corrupted_dir}")
     
     # Use all available CPU cores
-    max_workers = multiprocessing.cpu_count()
+    cpu_count = multiprocessing.cpu_count()
+    if platform.system() == 'Windows' and not UNLOCKED:
+        # Windows ProcessPoolExecutor has a maximum of 61 workers (unless unlocked)
+        max_workers = min(cpu_count, 61)
+        if cpu_count > 61:
+            print(f"Detected {cpu_count} CPU threads, but Windows limits ProcessPoolExecutor to 61 workers.")
+            print("Install 'unlock-processpool-win' package to use all cores: pip install unlock-processpool-win")
+    else:
+        max_workers = cpu_count
+        if UNLOCKED:
+            print(f"Using unlock-processpool-win to bypass Windows 61-worker limit")
     print(f"Using {max_workers} worker processes for compression...")
     print("-" * 80)