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 # pymp4dump
-pymp4dump is a Python-based tool for parsing, inspecting, and extracting data from MP4 / ISO BMFF (CENC) files.
+
+**pymp4dump** is a Python-based tool for parsing, inspecting, and extracting data from **MP4 / ISO BMFF (CENC)** files.
+It focuses on accurate box-level parsing, DRM metadata extraction, and structured output for analysis workflows.
+
+---
+
+## Features
+
+* Full parsing of **MP4 / ISO BMFF box structure**
+* Support for **fragmented (fMP4) and non-fragmented files**
+* Detailed decoding of:
+
+  * Track metadata (video, audio, subtitles)
+  * Sample tables (stsz, stsc, stco, etc.)
+  * Codec configurations (avcC, hvcC, dvcC, etc.)
+* Built-in support for **DRM systems**:
+
+  * **PlayReady**
+  * **Widevine**
+  * **FairPlay**
+* Extraction of:
+
+  * **Complete PSSH boxes (base64 / hex)**
+  * **Inner PSSH payload (base64)**
+* JSON and human-readable output modes
+* Track dumping (raw sample extraction)
+* Stream-safe parsing for large files
+
+---
+
+## Requirements
+
+* Python 3.9 or higher
+
+No external dependencies required (standard library only).
+
+---
+
+## Usage
+
+Basic dump:
+
+```bash
+python pymp4dump.py input.mp4
+```
+
+With verbosity:
+
+```bash
+python pymp4dump.py input.mp4 --verbosity 2
+```
+
+JSON output:
+
+```bash
+python pymp4dump.py input.mp4 --format json
+```
+
+---
+
+## DRM / PSSH Extraction
+
+Extract full PlayReady PSSH (base64):
+
+```bash
+python pymp4dump.py input.mp4 --extract-playready-pssh
+```
+
+Extract only PlayReady payload (base64):
+
+```bash
+python pymp4dump.py input.mp4 --extract-playready-payload
+```
+
+---
+
+## Track Dumping
+
+Dump a specific track:
+
+```bash
+python pymp4dump.py input.mp4 --track 1
+```
+
+Output will be:
+
+```
+input.mp4.1
+```
+
+> Note: Decryption keys are accepted for CLI compatibility but **decryption is not performed**.
+
+---
+
+## Python Usage
+
+Basic PlayReady extraction:
+
+```python
+from pymp4dump import extract_playready_pssh_from_mp4
+
+pssh = extract_playready_pssh_from_mp4("init.mp4")
+
+print("PlayReady PSSH:", pssh)
+```
+
+Alternative helper:
+
+```python
+from pymp4dump import extract_playready_pssh_payload_from_mp4
+
+payload = extract_playready_pssh_payload_from_mp4("init.mp4")
+print("PlayReady Payload:", payload)
+```
+
+---
+
+## Notes
+
+This project is inspired by tools like **Bento4 mp4dump**, but implemented fully in Python for flexibility and integration into custom workflows.
+
+It is especially useful for:
+
+* DRM analysis
+* Media reverse engineering
+* Automation pipelines (Widevine / PlayReady workflows)
+* Inspecting initialization segments (`init.mp4`)
+
+---
+
+## Limitations
+
+* No media decryption is performed
+* Track dumping outputs raw samples only
+* Some proprietary or uncommon box types may not be fully decoded
+
+---
+
+## Issues and Support
+
+If you encounter any issues, please open an issue in the repository.
+Support and updates will be provided as time permits.
+
+---
+
+## Acknowledgements
+
+Inspired by:
+
+* Bento4
+* ISO BMFF specification
+* DRM reverse engineering community