Implement video processing module with FFmpeg conversion, OpenCV metadata extraction, and file system repository

- Added FFmpegVideoConverter for video format conversion using FFmpeg.
- Implemented NoOpVideoConverter for scenarios where FFmpeg is unavailable.
- Created OpenCVMetadataExtractor for extracting video metadata.
- Developed FileSystemVideoRepository for managing video files in the file system.
- Integrated video services with dependency injection in VideoModule.
- Established API routes for video management and streaming.
- Added request/response schemas for video metadata and streaming information.
- Implemented caching mechanisms for video streaming.
- Included error handling and logging throughout the module.

docs/API_CHANGES_SUMMARY.md

@@ -1,6 +1,38 @@
-# API Changes Summary: Camera Settings and Filename Handling
+# API Changes Summary: Camera Settings and Video Format Updates
 
 ## Overview
+This document tracks major API changes including camera settings enhancements and the MP4 video format update.
+
+## 🎥 Latest Update: MP4 Video Format (v2.1)
+**Date**: August 2025
+
+**Major Changes**:
+- **Video Format**: Changed from AVI/XVID to MP4/MPEG-4 format
+- **File Extensions**: New recordings use `.mp4` instead of `.avi`
+- **File Size**: ~40% reduction in file sizes
+- **Streaming**: Better web browser compatibility
+
+**New Configuration Fields**:
+```json
+{
+  "video_format": "mp4",      // File format: "mp4" or "avi"
+  "video_codec": "mp4v",      // Video codec: "mp4v", "XVID", "MJPG"
+  "video_quality": 95         // Quality: 0-100 (higher = better)
+}
+```
+
+**Frontend Impact**:
+- ✅ Better streaming performance and browser support
+- ✅ Smaller file sizes for faster transfers
+- ✅ Universal HTML5 video player compatibility
+- ✅ Backward compatible with existing AVI files
+
+**Documentation**: See [MP4 Format Update Guide](MP4_FORMAT_UPDATE.md)
+
+---
+
+## Previous Changes: Camera Settings and Filename Handling
+
 Enhanced the `POST /cameras/{camera_name}/start-recording` API endpoint to accept optional camera settings (shutter speed/exposure, gain, and fps) and ensure all filenames have datetime prefixes.
 
 ## Changes Made