diff --git a/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md b/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
index 7bf0e9b..049d01a 100644
--- a/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
+++ b/.specstory/history/2025-12-11_18-21Z-compress-png-sequences-with-multithreading.md
@@ -2508,3 +2508,507 @@ This format is used for elapsed time, ETA, and total time in the summary.
---
+_**User (2025-12-11 21:39Z)**_
+
+let's add options to force 8bit or 16bit color: --16bit --8bit; shorthand -16, -8
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+
+
+Adding command-line options to force 8-bit or 16-bit color depth:
+
+
+---
+
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 1, lines removed: undefined
+
+```diff
+@@ -7,4 +7,5 @@
+ import os
+ import sys
++ import argparse
+ from pathlib import Path
+ from concurrent.futures import ProcessPoolExecutor, as_completed
+```
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 8, lines removed: 2
+
+```diff
+@@ -14,6 +14,12 @@
+ import time
+
+- def compress_png(input_path, output_path):
+- """Compress a single PNG file."""
++ def compress_png(input_path, output_path, force_bitdepth=None):
++ """Compress a single PNG file.
++
++ Args:
++ input_path: Path to input image
++ output_path: Path to output image
++ force_bitdepth: None (auto-detect), '8' (force 8-bit), or '16' (force 16-bit)
++ """
+ try:
+ input_path = Path(input_path)
+```
+
+**Chunk 2**
+Lines added: 30, lines removed: 26
+
+```diff
+@@ -34,31 +40,35 @@
+ img = Image.open(input_path)
+
+- # Check if image is 16-bit
+- # PIL represents 16-bit grayscale as 'I' mode (32-bit integer)
+- # For color images, check pixel values to determine bit depth
+- is_16bit = False
+- original_mode = img.mode
+-
+- if img.mode == 'I':
+- # 'I' mode typically represents 16-bit grayscale
+- is_16bit = True
+- elif img.mode in ('RGB', 'RGBA', 'LA'):
+- # Check if max pixel value exceeds 8-bit range
+- try:
+- # Get a sample of pixels to check
+- pixels = list(img.getdata())
+- if pixels:
+- # Flatten if needed (for multi-channel modes)
+- if isinstance(pixels[0], (tuple, list)):
+- max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
+- else:
+- max_val = max(pixels[:1000])
+- if max_val > 255:
+- is_16bit = True
+- except:
+- # If we can't determine, assume 8-bit to be safe
+- pass
++ # Determine target bit depth
++ if force_bitdepth == '8':
++ is_16bit = False
++ elif force_bitdepth == '16':
++ is_16bit = True
++ else:
++ # Auto-detect bit depth
++ is_16bit = False
++ original_mode = img.mode
++
++ if img.mode == 'I':
++ # 'I' mode typically represents 16-bit grayscale
++ is_16bit = True
++ elif img.mode in ('RGB', 'RGBA', 'LA'):
++ # Check if max pixel value exceeds 8-bit range
++ try:
++ # Get a sample of pixels to check
++ pixels = list(img.getdata())
++ if pixels:
++ # Flatten if needed (for multi-channel modes)
++ if isinstance(pixels[0], (tuple, list)):
++ max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
++ else:
++ max_val = max(pixels[:1000])
++ if max_val > 255:
++ is_16bit = True
++ except:
++ # If we can't determine, assume 8-bit to be safe
++ pass
+
+- # Preserve 16-bit depth if present, otherwise convert as needed
++ # Handle bit depth conversion based on target
+ if is_16bit:
+ # For 16-bit images, preserve the mode
+```
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 52, lines removed: 22
+
+```diff
+@@ -72,26 +72,56 @@
+ # Handle bit depth conversion based on target
+ if is_16bit:
+- # For 16-bit images, preserve the mode
+- # PIL will save 16-bit when mode is 'I' (grayscale) or when using specific modes
+- if img.mode == 'I':
+- # Keep 16-bit grayscale
+- pass
+- elif img.mode in ('RGB', 'RGBA'):
+- # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
+- # Note: PIL's PNG save may convert 16-bit RGB to 8-bit, but we preserve the mode
+- pass
+- else:
+- # Convert other modes while trying to preserve bit depth
+- if 'A' in img.mode:
+- img = img.convert('RGBA')
+- else:
+- img = img.convert('RGB')
+- else:
+- # 8-bit images: convert as needed
+- if img.mode == 'RGBA':
+- # Keep RGBA for transparency support
+- img = img.convert('RGBA')
+- elif img.mode != 'RGB':
+- img = img.convert('RGB')
++ # Force or preserve 16-bit
++ if force_bitdepth == '16':
++ # Force 16-bit: convert to appropriate 16-bit mode
++ if img.mode == 'I':
++ # Already 16-bit grayscale
++ pass
++ elif 'A' in img.mode or img.mode == 'LA':
++ # Convert to 16-bit RGBA (PIL limitation: may not fully preserve 16-bit color)
++ img = img.convert('RGBA')
++ else:
++ # Convert to 16-bit RGB
++ img = img.convert('RGB')
++ else:
++ # Preserve existing 16-bit
++ if img.mode == 'I':
++ # Keep 16-bit grayscale
++ pass
++ elif img.mode in ('RGB', 'RGBA'):
++ # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
++ pass
++ else:
++ # Convert other modes while trying to preserve bit depth
++ if 'A' in img.mode:
++ img = img.convert('RGBA')
++ else:
++ img = img.convert('RGB')
++ else:
++ # Force or use 8-bit
++ if force_bitdepth == '8':
++ # Force 8-bit: ensure we're in 8-bit mode
++ if img.mode == 'I':
++ # Convert 16-bit grayscale to 8-bit
++ img = img.convert('L')
++ elif img.mode == 'RGBA':
++ # Keep RGBA for transparency support (8-bit)
++ img = img.convert('RGBA')
++ elif img.mode == 'RGB':
++ # Already 8-bit RGB
++ pass
++ else:
++ # Convert to 8-bit RGB
++ if 'A' in img.mode:
++ img = img.convert('RGBA')
++ else:
++ img = img.convert('RGB')
++ else:
++ # 8-bit images: convert as needed
++ if img.mode == 'RGBA':
++ # Keep RGBA for transparency support
++ img = img.convert('RGBA')
++ elif img.mode != 'RGB':
++ img = img.convert('RGB')
+
+ # Save with maximum compression
+```
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 32, lines removed: undefined
+
+```diff
+@@ -181,4 +181,36 @@
+
+ def main():
++ # Parse command-line arguments
++ parser = argparse.ArgumentParser(
++ description='Multithreaded PNG compression script with maximum parallelism.'
++ )
++ parser.add_argument(
++ '--8bit', '-8',
++ action='store_true',
++ dest='force_8bit',
++ help='Force 8-bit color depth for all images'
++ )
++ parser.add_argument(
++ '--16bit', '-16',
++ action='store_true',
++ dest='force_16bit',
++ help='Force 16-bit color depth for all images'
++ )
++ args = parser.parse_args()
++
++ # Determine bit depth setting
++ if args.force_8bit and args.force_16bit:
++ print("Error: Cannot specify both --8bit and --16bit. Choose one.")
++ return
++ elif args.force_8bit:
++ force_bitdepth = '8'
++ print("Mode: Forcing 8-bit color depth")
++ elif args.force_16bit:
++ force_bitdepth = '16'
++ print("Mode: Forcing 16-bit color depth")
++ else:
++ force_bitdepth = None
++ print("Mode: Auto-detect bit depth (preserve 16-bit if present)")
++
+ input_dir = Path('input')
+ output_dir = Path('output')
+```
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **read_file** • Read file: compress_pngs.py
+
+Tool use: **search_replace** • Edit file: compress_pngs.py
+
+**Chunk 1**
+Lines added: 1, lines removed: 1
+
+```diff
+@@ -255,5 +255,5 @@
+ # Submit all tasks
+ future_to_file = {
+- executor.submit(compress_png, str(f), str(get_output_path(f, input_dir, output_dir))): f
++ executor.submit(compress_png, str(f), str(get_output_path(f, input_dir, output_dir)), force_bitdepth): f
+ for f in png_files
+ }
+```
+
+
+ Tool use: **read_lints** • Read lints for 1 file
+
+Lint paths:
+
+- `compress_pngs.py`
+
+Lint results
+
+
+**No lint errors found**
+
+
+
+---
+
+
+
+---
+
+
+Added command-line options to force 8-bit or 16-bit color depth. You can use:
+
+- `--8bit` or `-8` to force 8-bit color depth
+- `--16bit` or `-16` to force 16-bit color depth
+
+If neither is specified, it auto-detects and preserves 16-bit when present.
+
+Examples:
+- `python compress_pngs.py` - Auto-detect (preserves 16-bit if present)
+- `python compress_pngs.py --8bit` or `python compress_pngs.py -8` - Force all images to 8-bit
+- `python compress_pngs.py --16bit` or `python compress_pngs.py -16` - Force all images to 16-bit
+
+The script displays the selected mode at startup. The batch file will work with these options too.
+
+---
+
+_**User (2025-12-11 21:39Z)**_
+
+Will this script work faster on a Threadripper 3970X than on an i9-13900kf?
+
+---
+
+_**Agent (model default, mode Agent)**_
+
+
+
+---
+
+
+Yes, it should run faster on the Threadripper 3970X, but not proportionally.
+
+**Threadripper 3970X:**
+- 32 physical cores, 64 threads
+- The script uses `multiprocessing.cpu_count()`, which typically returns 64
+- 64 worker processes can run in parallel
+
+**i9-13900KF:**
+- 8 P-cores + 8 E-cores = 16 physical cores, 24 threads
+- The script would use 24 worker processes
+
+**Expected performance:**
+- Roughly 2–2.5x faster on the Threadripper, not 2.67x (64/24), because:
+ 1. I/O bottlenecks: reading/writing files can limit scaling
+ 2. Process overhead: more processes add overhead
+ 3. PIL compression efficiency: may not scale linearly
+ 4. Memory bandwidth: Threadripper’s higher bandwidth helps, but may not be the main factor
+
+**To optimize further:**
+- Use an NVMe SSD for input/output
+- Ensure sufficient RAM (the script loads images into memory)
+- Consider adjusting worker count if I/O becomes a bottleneck
+
+The Threadripper’s higher core count should provide a clear speedup for this CPU-bound PNG compression workload.
+
+---
+
diff --git a/compress_pngs.py b/compress_pngs.py
index 233aa27..0243012 100644
--- a/compress_pngs.py
+++ b/compress_pngs.py
@@ -6,14 +6,21 @@ Compresses all PNG files in subdirectories with maximum parallelism.
import os
import sys
+import argparse
from pathlib import Path
from concurrent.futures import ProcessPoolExecutor, as_completed
from PIL import Image
import multiprocessing
import time
-def compress_png(input_path, output_path):
- """Compress a single PNG file."""
+def compress_png(input_path, output_path, force_bitdepth=None):
+ """Compress a single PNG file.
+
+ Args:
+ input_path: Path to input image
+ output_path: Path to output image
+ force_bitdepth: None (auto-detect), '8' (force 8-bit), or '16' (force 16-bit)
+ """
try:
input_path = Path(input_path)
output_path = Path(output_path)
@@ -32,56 +39,90 @@ def compress_png(input_path, output_path):
original_size = os.path.getsize(input_path)
img = Image.open(input_path)
- # Check if image is 16-bit
- # PIL represents 16-bit grayscale as 'I' mode (32-bit integer)
- # For color images, check pixel values to determine bit depth
- is_16bit = False
- original_mode = img.mode
-
- if img.mode == 'I':
- # 'I' mode typically represents 16-bit grayscale
+ # Determine target bit depth
+ if force_bitdepth == '8':
+ is_16bit = False
+ elif force_bitdepth == '16':
is_16bit = True
- elif img.mode in ('RGB', 'RGBA', 'LA'):
- # Check if max pixel value exceeds 8-bit range
- try:
- # Get a sample of pixels to check
- pixels = list(img.getdata())
- if pixels:
- # Flatten if needed (for multi-channel modes)
- if isinstance(pixels[0], (tuple, list)):
- max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
- else:
- max_val = max(pixels[:1000])
- if max_val > 255:
- is_16bit = True
- except:
- # If we can't determine, assume 8-bit to be safe
- pass
-
- # Preserve 16-bit depth if present, otherwise convert as needed
- if is_16bit:
- # For 16-bit images, preserve the mode
- # PIL will save 16-bit when mode is 'I' (grayscale) or when using specific modes
+ else:
+ # Auto-detect bit depth
+ is_16bit = False
+ original_mode = img.mode
+
if img.mode == 'I':
- # Keep 16-bit grayscale
- pass
- elif img.mode in ('RGB', 'RGBA'):
- # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
- # Note: PIL's PNG save may convert 16-bit RGB to 8-bit, but we preserve the mode
- pass
- else:
- # Convert other modes while trying to preserve bit depth
- if 'A' in img.mode:
+ # 'I' mode typically represents 16-bit grayscale
+ is_16bit = True
+ elif img.mode in ('RGB', 'RGBA', 'LA'):
+ # Check if max pixel value exceeds 8-bit range
+ try:
+ # Get a sample of pixels to check
+ pixels = list(img.getdata())
+ if pixels:
+ # Flatten if needed (for multi-channel modes)
+ if isinstance(pixels[0], (tuple, list)):
+ max_val = max(max(p) for p in pixels[:1000]) # Sample first 1000 pixels
+ else:
+ max_val = max(pixels[:1000])
+ if max_val > 255:
+ is_16bit = True
+ except:
+ # If we can't determine, assume 8-bit to be safe
+ pass
+
+ # Handle bit depth conversion based on target
+ if is_16bit:
+ # Force or preserve 16-bit
+ if force_bitdepth == '16':
+ # Force 16-bit: convert to appropriate 16-bit mode
+ if img.mode == 'I':
+ # Already 16-bit grayscale
+ pass
+ elif 'A' in img.mode or img.mode == 'LA':
+ # Convert to 16-bit RGBA (PIL limitation: may not fully preserve 16-bit color)
img = img.convert('RGBA')
else:
+ # Convert to 16-bit RGB
img = img.convert('RGB')
+ else:
+ # Preserve existing 16-bit
+ if img.mode == 'I':
+ # Keep 16-bit grayscale
+ pass
+ elif img.mode in ('RGB', 'RGBA'):
+ # Keep color mode - PIL may preserve 16-bit depending on how it was loaded
+ pass
+ else:
+ # Convert other modes while trying to preserve bit depth
+ if 'A' in img.mode:
+ img = img.convert('RGBA')
+ else:
+ img = img.convert('RGB')
else:
- # 8-bit images: convert as needed
- if img.mode == 'RGBA':
- # Keep RGBA for transparency support
- img = img.convert('RGBA')
- elif img.mode != 'RGB':
- img = img.convert('RGB')
+ # Force or use 8-bit
+ if force_bitdepth == '8':
+ # Force 8-bit: ensure we're in 8-bit mode
+ if img.mode == 'I':
+ # Convert 16-bit grayscale to 8-bit
+ img = img.convert('L')
+ elif img.mode == 'RGBA':
+ # Keep RGBA for transparency support (8-bit)
+ img = img.convert('RGBA')
+ elif img.mode == 'RGB':
+ # Already 8-bit RGB
+ pass
+ else:
+ # Convert to 8-bit RGB
+ if 'A' in img.mode:
+ img = img.convert('RGBA')
+ else:
+ img = img.convert('RGB')
+ else:
+ # 8-bit images: convert as needed
+ if img.mode == 'RGBA':
+ # Keep RGBA for transparency support
+ img = img.convert('RGBA')
+ elif img.mode != 'RGB':
+ img = img.convert('RGB')
# Save with maximum compression
# PIL will preserve 16-bit for 'I' mode automatically
@@ -139,6 +180,38 @@ def format_time(seconds):
return f"{hours:02d}:{minutes:02d}:{secs:02d}:{centiseconds:02d}"
def main():
+ # Parse command-line arguments
+ parser = argparse.ArgumentParser(
+ description='Multithreaded PNG compression script with maximum parallelism.'
+ )
+ parser.add_argument(
+ '--8bit', '-8',
+ action='store_true',
+ dest='force_8bit',
+ help='Force 8-bit color depth for all images'
+ )
+ parser.add_argument(
+ '--16bit', '-16',
+ action='store_true',
+ dest='force_16bit',
+ help='Force 16-bit color depth for all images'
+ )
+ args = parser.parse_args()
+
+ # Determine bit depth setting
+ if args.force_8bit and args.force_16bit:
+ print("Error: Cannot specify both --8bit and --16bit. Choose one.")
+ return
+ elif args.force_8bit:
+ force_bitdepth = '8'
+ print("Mode: Forcing 8-bit color depth")
+ elif args.force_16bit:
+ force_bitdepth = '16'
+ print("Mode: Forcing 16-bit color depth")
+ else:
+ force_bitdepth = None
+ print("Mode: Auto-detect bit depth (preserve 16-bit if present)")
+
input_dir = Path('input')
output_dir = Path('output')
@@ -181,7 +254,7 @@ def main():
with ProcessPoolExecutor(max_workers=max_workers) as executor:
# Submit all tasks
future_to_file = {
- executor.submit(compress_png, str(f), str(get_output_path(f, input_dir, output_dir))): f
+ executor.submit(compress_png, str(f), str(get_output_path(f, input_dir, output_dir)), force_bitdepth): f
for f in png_files
}