fixes filter on MPT-transition. Add a high quality filter wir anti-aliasing

CHANGELOG.md

@@ -1,5 +1,49 @@
 # Changelog
 
+## [v1.2.1] - 2024-12-20
+### Added
+- **High-Quality Filter Implementation**: Direct Form II Transposed filter structure for improved numerical stability
+- **Filter Warm-Up**: Proper filter initialization to avoid transients, especially important for MPT transforms
+- **Anti-Aliasing in Resampling**: Automatic anti-aliasing filter when downsampling to prevent aliasing artifacts
+
+### Fixed
+- **MPT Filter Application**: MPT IRs now correctly use the filtered recorded sweep (same as RAW IRs)
+- **Filter Response at Lower Sample Rates**: Fixed filter response accuracy when resampling to 48kHz and other lower sample rates
+- **Resampling Artifacts**: Added proper anti-aliasing to prevent frequency aliasing when downsampling
+
+### Changed
+- **Filter Quality**: Improved filter implementation with high-precision coefficient calculation and proper state management
+- **Filter Artifacts**: Reduced artifacts in steep filters (48+ dB/octave) through better numerical stability
+
+### Technical Improvements
+- **Direct Form II Transposed**: More numerically stable filter structure for cascaded filters
+- **Filter Warm-Up**: Pre-initialization of filter state to eliminate transients
+- **Anti-Aliasing**: Steep low-pass filter (48 dB/octave) applied before downsampling to prevent aliasing
+
+## [v1.2.0] - 2024-12-20
+### Added
+- **Cabpack Generation**: Complete cabpack creation with IRs in 9 different formats organized in structured directory trees
+- **Default Mode**: Run without command-line options for automatic cabpack generation from current directory
+- **Executable Directory Detection**: Automatic detection of binary location for double-click support in Finder/Explorer
+- **Automatic File Organization**: Support for `selection.txt` and `ambient.txt` files to automatically organize IRs
+- **Mixes Folder Support**: Automatic conversion of ready-to-use IRs from `mixes` folder to all cabpack formats
+- **IR Filename in Plots**: IR filenames now displayed in plot titles for better identification
+- **Cabpack Defaults**: Automatic defaults for cabpack mode (fade-ms: 10, lowcut: 40Hz)
+- **Plots for Mixes**: Automatic plot generation for mix IRs in `plots/mixes` folder
+- **Logo in Plots**: Valhallir logo automatically displayed in upper-left corner of all generated plots (embedded in binary)
+
+### Changed
+- **Optional Command-Line Flags**: All main flags (`--sweep`, `--recorded`, `--output`) are now optional with intelligent defaults
+- **Default Sweep File**: Changed default sweep filename to `sweep.wav` (simpler naming)
+- **Output Directory**: IRs folder created one directory level up from recorded directory by default
+- **Directory Structure**: Added `mixes` subfolder to each format folder (only created if `mixes` folder exists)
+- **Conditional Folder Creation**: `selection`, `ambient mics`, and `mixes` folders are only created if the corresponding files/folders exist in the recorded directory
+
+### Technical Improvements
+- **Smart Path Detection**: Uses executable directory when double-clicked, current directory when run from command line
+- **Enhanced Logging**: Better progress information and path logging for debugging
+- **Improved Error Handling**: Graceful handling of missing optional files (selection.txt, ambient.txt, mixes folder)
+
 ## [v1.1.0] - 2024-12-19
 ### Added
 - **IR Visualization**: New `--plot-ir` flag to generate frequency response and waveform plots