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Added new section on EFM decode tools
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‎wiki-default/Development/tools-metadata-format.md‎

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‎wiki-default/EFM-Tools/efm-decoder-audio.md‎

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# efm-decoder-audio
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**EFM Data24 to Audio Decoder**
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## Overview
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efm-decoder-audio converts Data24 sections into 16-bit stereo PCM audio according to IEC 60908 specifications. This tool handles the final stage of audio decoding for CD audio and LaserDisc digital audio tracks, producing standard WAV files with detailed metadata.
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## Usage
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```bash
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efm-decoder-audio [options] <input.d24> <output.wav>
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```
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## Options
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### Standard Options
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- `-h, --help` - Display help information
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- `-v, --version` - Display version information
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- `-d, --debug` - Show debug output
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- `-q, --quiet` - Suppress info and warning messages
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### Audio Processing
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- `--audacity-labels` - Output WAV metadata as Audacity labels
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- `--no-audio-concealment` - Do not conceal errors in the audio data
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- `--zero-pad` - Zero pad the audio data from 00:00:00
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- `--no-wav-header` - Output raw audio data without WAV header
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### Debug Options
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- `--show-audio` - Show Audio frame data
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- `--show-audio-debug` - Show Data24 to audio decoding debug
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- `--show-audio-correction-debug` - Show Audio correction debug
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- `--show-all-debug` - Show all decoding debug
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### Arguments
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- `input` - Input Data24 section file (from efm-decoder-d24)
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- `output` - Output WAV audio file
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## Processing Pipeline
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The decoding sequence performed by efm-decoder-audio:
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1. **Data24 Sections** → Input from efm-decoder-d24 (or stdin via Unix pipes)
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2. **Audio Frame Extraction** → Extract 16-bit stereo samples
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3. **Error Concealment** → Interpolate or silence corrupted samples
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4. **WAV Generation** → Standard 44.1kHz 16-bit stereo output
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5. **Metadata Export** → Optional Audacity label file generation
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**Unix Pipelining**: efm-decoder-audio supports stdin/stdout using `-`, allowing direct connection to other EFM decoder tools without intermediate files.
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## Audio Output Format
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### WAV Specifications
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- **Sample Rate**: 44.1 kHz (44,100 samples/second)
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- **Bit Depth**: 16-bit signed integer
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- **Channels**: 2 (stereo)
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- **Format**: Standard WAV with proper headers
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### Quality Metrics
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Each Data24 section (1/75 second) produces:
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- 588 stereo sample pairs (44,100 ÷ 75 = 588)
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- 2,352 bytes of audio data per section
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- Total data rate: 176.4 KB/second
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## Error Concealment
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The tool provides sophisticated error handling:
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### Concealment Methods
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- **Interpolation**: Average of adjacent valid samples
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- **Silencing**: Zero amplitude for uncorrectable errors
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- **Detection**: Flags all concealed/silenced regions
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### Concealment Control
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- Default behavior performs automatic concealment for best audio quality
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- Use `--no-audio-concealment` option to disable concealment
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## Metadata Output
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### Audacity Labels Format
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When `--audacity-labels` is specified, generates a .txt file containing:
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- **Timestamp precision**: Millisecond accuracy for individual samples
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- **Error locations**: Concealed and silenced sample positions
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- **Track information**: CD track boundaries (when available)
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- **Time codes**: Both Audacity time and CDDA format timestamps
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### Example Metadata
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```
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2038.365964 2038.366100 Silenced: 33:58:27
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0.000000 175.333333 Track: 01 [00:00:00-02:53:25]
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175.346667 470.520000 Track: 02 [00:00:00-04:55:13]
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```
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## Pipeline Integration
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### Input Requirements
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- Data24 sections from efm-decoder-d24
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- Properly error-corrected data (CIRC processing completed)
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### Common Workflows
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#### Standard Audio Extraction
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```bash
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# Complete pipeline for audio using Unix pipes
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efm-decoder-f2 input.efm - | efm-decoder-d24 - - | efm-decoder-audio - output.wav --audacity-labels
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# Alternative: step by step with files
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efm-decoder-f2 input.efm temp.f2
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efm-decoder-d24 temp.f2 temp.d24
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efm-decoder-audio temp.d24 output.wav --audacity-labels
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```
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#### Multi-Source Quality Enhancement
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```bash
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# Stack multiple sources first
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efm-stacker-f2 source1.f2 source2.f2 source3.f2 stacked.f2
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efm-decoder-d24 stacked.f2 stacked.d24
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efm-decoder-audio stacked.d24 output.wav --audacity-labels
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```
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## Performance Considerations
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- Real-time processing: ~75x faster than real-time on modern hardware
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- Memory usage: Minimal (processes sections sequentially)
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- Quality depends heavily on CIRC correction effectiveness from efm-decoder-d24

‎wiki-default/EFM-Tools/efm-decoder-d24.md‎

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# efm-decoder-d24
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**EFM F2 Section to Data24 Section Decoder**
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## Overview
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efm-decoder-d24 takes F2 sections as input (from efm-decoder-f2) and decodes them into Data24 sections. This tool performs the critical CIRC error correction (C1 and C2) and unscrambling according to ECMA-130 specifications.
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Data24 sections are an intermediate format that can be interpreted as either audio data (IEC 60908) or sector-based data (ECMA-130).
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## Usage
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```bash
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efm-decoder-d24 [options] <input.f2> <output.d24>
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```
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## Options
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- `-h, --help` - Display help information
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- `-v, --version` - Display version information
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- `-d, --debug` - Show debug output
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- `-q, --quiet` - Suppress info and warning messages
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- `--show-f1` - Show F1 frame data
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- `--show-data24` - Show Data24 frame data
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- `--show-f2-debug` - Show F2 to F1 decoding debug
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- `--show-f1-debug` - Show F1 to Data24 decoding debug
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- `--show-all-debug` - Show all debug options
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### Arguments
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- `input` - Input F2 section file (from efm-decoder-f2)
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- `output` - Output Data24 section file
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## Processing Pipeline
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The decoding sequence performed by efm-decoder-d24:
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1. **F2 Sections** → Input from efm-decoder-f2 (or stdin via Unix pipes)
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2. **F1 Sections** → CIRC error correction applied
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3. **Data24 Sections** → Byte order corrected, ready for final decoding
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**Unix Pipelining**: efm-decoder-d24 supports stdin/stdout using `-`, allowing seamless integration in EFM processing pipelines.
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## Technical Details
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### CIRC Error Correction
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The tool implements Cross-Interleaved Reed-Solomon Code (CIRC) error correction:
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- **C1 Correction**: First level error correction
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- **C2 Correction**: Second level error correction
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- **Unscrambling**: Data de-interleaving according to ECMA-130
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### Data24 Format
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Data24 sections consist of:
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- 98 frames per section (representing 1/75th second)
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- 24 bytes per frame (2352 bytes total per section)
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- Corrected byte order (unlike F1 frames which have reversed byte order)
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- Preserved section metadata from F2 input
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### Error Handling
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The CIRC system can:
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- **Detect** up to 4 symbol errors per codeword
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- **Correct** up to 2 symbol errors per codeword
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- **Flag** uncorrectable errors for concealment by downstream tools
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## Output Format
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Data24 sections can be processed by either:
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- `efm-decoder-audio` - For audio decoding (CD audio, LaserDisc digital audio)
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- `efm-decoder-data` - For data decoding (Domesday LaserDiscs, CD-ROM data)
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## Performance Notes
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- CIRC correction is computationally intensive
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- Error correction effectiveness depends on input quality
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- Heavily damaged sections may require multiple source stacking (efm-stacker-f2)

‎wiki-default/EFM-Tools/efm-decoder-data.md‎

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# efm-decoder-data
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**EFM Data24 to Binary Data Decoder**
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## Overview
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efm-decoder-data converts Data24 sections into ECMA-130 compliant binary data sectors. This tool handles data-mode EFM decoding for applications like Domesday LaserDiscs and CD-ROM data, performing Reed-Solomon Product Code (RSPC) error correction and producing raw binary output.
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## Usage
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```bash
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efm-decoder-data [options] <input.d24> <output.bin>
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```
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## Options
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- `-h, --help` - Display help information
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- `-v, --version` - Display version information
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- `-d, --debug` - Show debug output
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- `-q, --quiet` - Suppress info and warning messages
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- `--output-metadata` - Output bad sector map metadata file
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- `--show-rawsector` - Show raw sector frame data
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- `--show-rawsector-debug` - Show Data24 to raw sector decoding debug
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- `--show-sector-debug` - Show raw sector to sector decoding debug
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- `--show-sector-correction-debug` - Show sector correction debug
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- `--show-all-debug` - Show all decoding debug
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### Arguments
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- `input` - Input Data24 section file (from efm-decoder-d24)
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- `output` - Output binary data file
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## Processing Pipeline
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The decoding sequence performed by efm-decoder-data:
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1. **Data24 Sections** → Input from efm-decoder-d24 (or stdin via Unix pipes, 2352 bytes per section)
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2. **Raw Sectors** → Extract 2048-byte data sectors from each section
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3. **RSPC Error Correction** → Reed-Solomon Product Code correction
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4. **Sector Validation** → Mark sectors as valid or invalid
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5. **Binary Output** → Continuous binary data stream
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**Unix Pipelining**: efm-decoder-data supports stdin/stdout using `-`, enabling direct data extraction from EFM processing pipelines.
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## Technical Details
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### Data Format Conversion
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- **Input**: Data24 sections (2352 bytes each, representing 1/75 second)
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- **Processing**: Strip EFM parity and error correction overhead
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- **Output**: Pure data sectors (2048 bytes each)
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- **Efficiency**: ~87% data efficiency (2048/2352)
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### RSPC Error Correction
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Implements Reed-Solomon Product Code correction according to ECMA-130:
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- **Q Parity**: Outer code correction
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- **P Parity**: Inner code correction
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- **Sector-level**: All-or-nothing correction per 2048-byte sector
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- **Unscrambling**: Data de-interleaving for error correction
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### Error Handling
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Unlike audio decoding, data decoding is binary:
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- **Valid sectors**: Fully corrected, guaranteed accuracy
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- **Invalid sectors**: Uncorrectable, flagged in metadata
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- **No concealment**: Corrupted data is not interpolated
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## Metadata Output
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### Bad Sector Map
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When `--output-metadata` is specified, creates a text file listing invalid sector addresses:
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```
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```
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Each number represents a 2048-byte sector that could not be corrected.
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### Format
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- One sector address per line
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- Addresses are sequential (starting from 0)
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- Only invalid/uncorrectable sectors are listed
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- Can be used by downstream tools for error handling
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## Pipeline Integration
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### Input Requirements
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- Data24 sections from efm-decoder-d24
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- CIRC-corrected data (first-stage error correction completed)
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### Common Workflows
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#### Standard Data Extraction
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```bash
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# Complete pipeline for data using Unix pipes
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efm-decoder-f2 input.efm - | efm-decoder-d24 - - | efm-decoder-data - output.bin --output-metadata
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# Alternative: step by step with files
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efm-decoder-f2 input.efm temp.f2
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efm-decoder-d24 temp.f2 temp.d24
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efm-decoder-data temp.d24 output.bin --output-metadata
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```
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#### Domesday LaserDisc Workflow
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```bash
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# Extract data then verify VFS structure
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efm-decoder-data domesday.d24 domesday.bin --output-metadata
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vfs-verifier domesday.bin domesday_metadata.txt
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```
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#### Multi-Source Data Recovery
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```bash
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# Stack sources for better error correction
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efm-stacker-f2 disc1.f2 disc2.f2 disc3.f2 stacked.f2
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efm-decoder-d24 stacked.f2 stacked.d24
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efm-decoder-data stacked.d24 recovered.bin --output-metadata
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```
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## Output Verification
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The extracted binary data can be verified using:
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- `vfs-verifier` - For Domesday LaserDisc VFS structures
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- Standard file analysis tools
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- Checksum verification (if reference data available)

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