# Video Converter Script Development Plan

## 1. Project Goal
Create a standalone executable application (using Python) to convert video files into formats highly compatible with Davinci Resolve, ensuring optimal aspect ratio, video quality, and audio fidelity. The application should be user-friendly, accepting input file paths via CLI arguments, prompting for output locations (if not specified), and leveraging `ffmpeg` for robust conversion. The goal is a single executable that requires no external dependencies (like Python or `ffmpeg` installations) from the end-user.

## 2. Key Tools and Technologies
*   **Python:** For scripting the user interface, logic, and orchestrating `ffmpeg` commands.
    *   **`ffmpeg-python` library:** A robust Python binding for FFmpeg to simplify command construction and execution.
*   **`ffmpeg` & `ffprobe`:** The primary tools for video and audio conversion and analysis. These will be bundled with the final application.
*   **PyInstaller (or similar):** For packaging the Python script and bundled `ffmpeg`/`ffprobe` into a standalone executable.

**Inspiration Repositories:** We will review `xavier150/convert-video-for-Resolve` and `tkmxqrdxddd/davinci-video-converter` for insights into Davinci Resolve specific conversion strategies and `ffmpeg` command construction.
*   **`yt-dlp` (Optional, for future expansion):** While the current scope is local files, `yt-dlp` could be integrated later for direct downloading and converting from online sources.

## 3. Core Functionality and Requirements

### 3.1. User Interaction
*   **Input File Selection:** The script will prompt the user to provide the absolute path to the input video file.
*   **Output Directory Selection:** The script will ask the user for a desired output directory. If no directory is provided, it will default to the script's current working directory.
*   **Output File Naming:** Converted files will be named clearly. If the output directory is the same as the input file's directory, the output filename will be prefixed with `recoded_` (e.g., `recoded_original_file.mov`). Otherwise, a clear naming convention will be applied (e.g., append `_DR_compatible`).

### 3.2. Shell Environment (Re-evaluation)
*   The initial request mentioned confirming the shell type. However, `ffmpeg` commands executed via Python's `subprocess` module are generally shell-agnostic. The Python script itself will handle the execution. Therefore, explicit shell detection is likely unnecessary unless specific shell-dependent environment variables or configurations for `ffmpeg` or `yt-dlp` (if integrated later) become an issue. This point will be kept in mind for troubleshooting.

### 3.3. Davinci Resolve Compatibility - Codec and Format Selection

Based on the "DaVinci Resolve 18 Supported Codec List.pdf" and web search results, the following are recommended for optimal compatibility and editing performance in Davinci Resolve, especially for intermediate files:

#### Video Codecs (for Intermediate Editing)
*   **DNxHR / DNxHD:**
    *   **Container:** QuickTime (`.mov`)
    *   **Description:** Excellent intraframe codecs for Windows and Linux. DNxHR is for resolutions above 1080p, while DNxHD is for up to 1080p. They offer good performance and preserve quality.
    *   **Profiles:** HQ (High Quality) or HQX (Higher Quality, larger file size) are preferred.
    *   **FFmpeg Example:** `-c:v dnxhr -profile:v HQ` (or `HQX`)
*   **Apple ProRes:**
    *   **Container:** QuickTime (`.mov`)
    *   **Description:** High-quality, widely used, especially on macOS. FFmpeg can encode/decode on other OS. Davinci Resolve supports ProRes with alpha channels.
    *   **FFmpeg Example:** `-c:v prores_ks -profile:v 3` (for ProRes HQ, profile numbers vary)
*   **GoPro CineForm:**
    *   **Container:** QuickTime (`.mov`)
    *   **Description:** Another high-quality intermediate codec supported by Davinci Resolve.

#### Audio Codecs
*   **PCM (Pulse Code Modulation):**
    *   **Description:** Crucial for Linux users, as Davinci Resolve on Linux often has compatibility issues with AAC audio. PCM is uncompressed and widely compatible.
    *   **FFmpeg Example:** `-c:a pcm_s16le` (16-bit signed little-endian PCM)
*   **FLAC:**
    *   **Description:** A lossless audio codec, suitable as an alternative to PCM or for extracting audio separately if needed.
    *   **FFmpeg Example:** `-c:a flac`

#### Container Format
*   **QuickTime (`.mov`):** Generally recommended for intermediate files due to better stability and metadata handling with Davinci Resolve.

#### Quality and Settings
*   **Aspect Ratio:** The script should preserve the original aspect ratio of the input video. `ffmpeg` handles this by default unless specific scaling filters are applied.
*   **Resolution:** Maintain original resolution or convert to a Davinci Resolve-friendly resolution if necessary (e.g., for DNxHD/HR profiles).
*   **Bit Depth:** Aim for 10-bit color depth (e.g., `yuv422p10le` pixel format) if the source video supports it and Davinci Resolve Studio is used, to prevent banding and ensure higher quality.
*   **Bitrate:** For intermediate files, high bitrates are expected and desired to preserve quality.

### 3.4. Conversion Logic (using `ffmpeg`)
1.  **Analyze Input:** Use `ffprobe` to get detailed information about the input video (video codec, audio codec, resolution, aspect ratio, frame rate, bit depth).
2.  **Determine Output Parameters:** Based on the input analysis and user preferences (if any are added later), select the most appropriate Davinci Resolve compatible video and audio codecs, profiles, and pixel formats.
3.  **Construct `ffmpeg` Command:** Build the `ffmpeg` command dynamically.
    *   **Example for DNxHR/DNxHD with PCM audio:**
        ```bash
        ffmpeg -i "input.mp4" -c:v dnxhr -profile:v HQ -c:a pcm_s16le "output_DR_compatible.mov"
        ```
    *   **Considerations:**
        *   Handling different input audio codecs (e.g., converting AAC to PCM).
        *   Mapping all video and audio streams (`-map 0`).
        *   Potentially adding `-vf scale=w:h:force_original_aspect_ratio=decrease,pad=w:h:(ow-iw)/2:(oh-ih)/2` for specific aspect ratio handling if cropping/padding is desired, but generally, preserving original is default.

## 4. Development Steps

1.  **Initial Script Setup:** Create `main.py` with basic `argparse` for input/output paths.
2.  **Directory Creation:** Ensure output directory exists.
3.  **`ffprobe` Integration:** Implement a function to call `ffprobe` and parse its JSON output to get video/audio stream details.
4.  **`ffmpeg` Command Construction:** Develop logic to build the `ffmpeg` command based on `ffprobe` output and desired Davinci Resolve compatibility.
5.  **`ffmpeg` Execution:** Use `subprocess.run()` to execute the `ffmpeg` command, capturing stdout/stderr for logging.
6.  **Error Handling:** Add `try-except` blocks for file operations, `subprocess` calls, and `ffprobe` parsing.
7.  **Basic Testing:** Test with a few sample video files (e.g., H.264/AAC MP4) to ensure conversion to DNxHR/PCM MOV works.
8.  **Packaging and Bundling:** Use PyInstaller (or similar) to create standalone executables for target operating systems. This step will involve bundling the Python script, its dependencies, and the `ffmpeg`/`ffprobe` binaries. Note that packaging will be OS-specific (e.g., a Linux executable must be built on Linux).
9.  **Error Handling for Bundled Tools:** Implement checks to ensure bundled `ffmpeg`/`ffprobe` are accessible and provide clear error messages if not.

## 6. Directory and File Structure

To ensure a modular, maintainable, and scalable project, the following directory and file structure is proposed:

```
/home/joe/Cloud9/Documents/Obisdian/projects/Video Converter/
├── .sources_library/
│   ├── davinci_resolve_18_supported_codec_list.pdf
│   ├── davinci_resolve_20_2_2_info.md
│   ├── davinci_resolve_20_2_new_features.pdf
│   └── yt-dlp_readme.md
├── src/
│   ├── __init__.py             # Makes 'src' a Python package
│   ├── main.py                 # Main CLI entry point, argument parsing
│   ├── converter.py            # Core video conversion logic, ffmpeg calls
│   ├── utils.py                # Helper functions (ffprobe parsing, path handling, logging)
│   └── config.py               # Configuration settings (codec profiles, defaults)
├── tests/
│   ├── __init__.py
│   ├── test_converter.py       # Unit tests for converter.py
│   └── test_utils.py           # Unit tests for utils.py
├── .gitignore
├── DEVELOPMENT_PLAN.md
├── README.md
├── requirements.txt          # Python dependencies (e.g., ffmpeg-python)
└── build/                    # Output directory for packaged executables (PyInstaller)
```

**Explanation of Structure:**

*   **`.sources_library/`**: Contains all reference documents and downloaded resources.
*   **`src/`**: This directory will contain all the Python source code for the application.
    *   `__init__.py`: Marks `src` as a Python package.
    *   `main.py`: The primary entry point for the CLI. It will handle argument parsing (`argparse`) and orchestrate calls to `converter.py` and `utils.py`.
    *   `converter.py`: This module will encapsulate the core logic for video conversion. It will contain functions that take input file paths, desired output settings, and construct/execute `ffmpeg` commands using `ffmpeg-python`.
    *   `utils.py`: This module will house helper functions, such as:
        *   Parsing `ffprobe` output.
        *   Handling file path manipulations (e.g., adding `recoded_` prefix, resolving output paths).
        *   Basic file existence checks.
        *   Logging setup.
    *   `config.py`: For storing configurable parameters like default codec profiles, output formats, or any other settings that might be user-adjustable or need to be easily changed.
*   **`tests/`**: This directory will contain unit tests for the `src` modules.
    *   `__init__.py`: Marks `tests` as a Python package.
    *   `test_converter.py`: Tests for the conversion logic in `converter.py`.
    *   `test_utils.py`: Tests for utility functions in `utils.py`.
*   **`.gitignore`**: Standard Git ignore file.
*   **`DEVELOPMENT_PLAN.md`**: This detailed plan document.
*   **`README.md`**: Project overview.
*   **`requirements.txt`**: Will list all Python dependencies (e.g., `ffmpeg-python`). This is crucial for managing the project's environment.
*   **`build/`**: This directory will be created later by PyInstaller to store the packaged executables.

This structure promotes modularity, making the codebase easier to understand, test, and maintain. It separates concerns (CLI handling, core logic, utilities, configuration) into distinct modules.


