DLPR Requirements

Requirements analysis for the delta-snapshot-based replay format (*.dlpr) developed by the delta-play-replay project.

Background

The existing CaptureAge (CA) replay system utilizes an internal format (*.carz) to play recorded games. This format supports backward compatibility with older recorded games, allowing them to be replayed without running the original AoE2DE simulation. However, the *.carz format is primarily designed for internal debugging purposes and in-memory use, and not for long-term storage.

The goal is to create a new, standardized replay format that accommodates the requirements for efficient storage, improved replay functionalities, and broader community support.

Current System Overview

Existing CaptureAge Replay Format

• Format: *.carz (CaptureAge Replay Format)
• Purpose: Internal debugging, live spectating
• Limitations: Not optimized for long-term storage, primarily intended for in-memory use
• Features:
  • Backward compatibility with older games
  • Instant navigation to any point in the replay
  • No need for an AoE2DE instance to replay games

Functional Requirements

1. Backward Compatibility - Support existing replays recorded in previous versions of AoE2DE. Ensure compatibility with the internal *.carz format used by CaptureAge.

2. Delta-Snapshot System - Implement a delta-snapshot-based approach to efficiently capture game state changes. Generate patches representing state differences at fixed intervals (snapshots) and on-demand (events).

3. Conversion and Compatibility Tools - Develop a converter to transform existing recorded games into the new replay format. Update gRPC definitions to accommodate new replay functionalities.

4. Long-Term Storage - Optimize the format for persistent storage, ensuring that replays are compact and easily shareable. Include metadata for versioning and compatibility checks.

5. Improved Navigation and Spectator Features - Enable quick navigation to any point in the replay, both forwards and backwards. Integrate spectator tools to allow live game viewing without running the AoE2DE simulation.

6. Support for Live Games - Explore server-side conversion for live games to facilitate real-time spectating without AoE2DE instances. Stream delta-patch files to spectators to reduce local processing requirements.

7. Open Source and Community Support - Make the new replay format open source and freely available to the community.

8. Security and Integrity - Implement encryption and integrity checks to protect replay files from tampering.

9. Game Independence - Evaluate how far the existing delta-snapshot-based replay formats are game-independent. Consider making the format support other games in the Age of Empires franchise (AoE4, AoM:R, AoE3DE).

Non-Functional Requirements

1. Performance - Minimize overhead when generating and storing replays. Ensure smooth and responsive playback.

2. Scalability - Handle a wide range of game scenarios, from short matches to extensive tournaments. Support concurrent access by multiple tools.

3. Extensibility - Allow for future extensions without breaking existing compatibility.

Comparison to Existing Format

Future Considerations

• Community Involvement: Engage with the AoE2DE community to gather feedback and suggestions for the new replay format.
• Integration with Other Platforms: Explore opportunities to integrate with platforms like Twitch or YouTube for enhanced content creation and sharing.
• Further Optimizations: Continue researching ways to reduce the size of delta-snapshot files while maintaining rich functionality.