michael 1a1ed3048d wrote docker files and deployment instructions

2025-10-08 16:00:12 -05:00

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Video Accessibility Processing Platform - Software Specification

1. Executive Summary

The Video Accessibility Processing Platform is a comprehensive web application designed to automatically generate closed captions and audio descriptions for video content using artificial intelligence. The platform provides a complete workflow from video upload through AI processing, human quality control, multi-language translation, and final content delivery.

Core Capabilities:

Automated generation of closed captions and audio descriptions using Google Gemini 2.5 Pro
Multi-language translation and transcreation services
Professional quality control workflow for reviewers
Text-to-speech generation for audio descriptions
Role-based access control for clients, reviewers, and administrators
Real-time job status updates via WebSocket connections
Secure file storage and signed URL download system

Target Users:

Clients: Organizations needing video accessibility services
Reviewers: Professional accessibility specialists who review and approve content
Administrators: System administrators managing users and system operations

2. System Architecture

2.1 Technology Stack

Frontend:

React 18 with TypeScript
Vite for build tooling
TanStack Query for state management
React Router for navigation
Tailwind CSS for styling

Backend:

FastAPI (Python 3.11+) for REST API
Celery with Redis for background task processing
MongoDB Atlas for data storage
JWT authentication with HttpOnly refresh cookies

External Services:

Google Cloud Storage for file storage
Google Gemini 2.5 Pro for AI processing
Google Cloud Translate for language translation
ElevenLabs for text-to-speech synthesis

Infrastructure:

Docker containerization
Redis for caching and task queues
WebSocket support for real-time updates

2.2 System Components

┌─────────────────┐    ┌─────────────────┐    ┌─────────────────┐
│   React SPA     │    │   FastAPI       │    │   Celery        │
│   Frontend      │◄──►│   Backend       │◄──►│   Workers       │
└─────────────────┘    └─────────────────┘    └─────────────────┘
                                │                       │
                                ▼                       ▼
                       ┌─────────────────┐    ┌─────────────────┐
                       │   MongoDB       │    │   Redis         │
                       │   Database      │    │   Queue/Cache   │
                       └─────────────────┘    └─────────────────┘
                                │
                                ▼
                       ┌─────────────────┐
                       │ Google Cloud    │
                       │ Storage         │
                       └─────────────────┘

3. User Roles and Access Control

3.1 Role Definitions

Client Role:

Upload videos and create processing jobs
View own job status and progress
Download completed accessibility assets
Limited to own content only

Reviewer Role:

Access quality control dashboard
Review AI-generated content for accuracy
Edit VTT files (captions and audio descriptions)
Approve or reject English content
Perform final review of completed jobs
Access to all jobs in system

Admin Role:

Full system access including all reviewer capabilities
User management (create, edit, deactivate users)
System monitoring and health checks
Bulk operations and maintenance tasks
Access to audit logs and system statistics

3.2 Authentication System

JWT Token Management:

Access tokens stored in memory (15-minute expiry)
Refresh tokens stored in HttpOnly cookies (7-day expiry)
Automatic token refresh for active sessions
Secure logout with cookie clearing

Security Features:

Password hashing using bcrypt
CORS protection with configurable origins
Rate limiting on authentication endpoints
Session-based security with proper token rotation

4. Job Processing Workflow

4.1 Job Status State Machine

The system implements a comprehensive state machine for tracking job progress:

created → ingesting → ai_processing → pending_qc → approved_english → translating → tts_generating → pending_final_review → completed
                                         ↓
                                      rejected → (manual intervention required)
                                         ↓
                                   qc_feedback → (back to pending_qc after fixes)

Status Definitions:

created: Job record created, video uploaded to storage
ingesting: Video being processed for metadata extraction
ai_processing: AI analyzing video content and generating captions/audio descriptions
pending_qc: Awaiting human quality control review
approved_english: English content approved, ready for translation
rejected: Content rejected, requires client revision
qc_feedback: Reviewer provided feedback, awaiting fixes
translating: Processing multi-language translations
tts_generating: Generating audio files from text descriptions
pending_final_review: All content ready, awaiting final approval
completed: Job finished, all assets available for download

4.2 Processing Pipeline

Phase 1: Upload and Ingestion

Client uploads MP4 video file through web interface
File stored in Google Cloud Storage with unique job ID path
Job record created in MongoDB with metadata
Background Celery task queued for processing

Phase 2: AI Content Generation

Video file sent to Google Gemini 2.5 Pro API
AI generates:
- Plain text transcript
- Closed captions in WebVTT format
- Audio description script in WebVTT format
- Confidence score for generated content
Generated content stored in GCS and linked to job
Job status updated to pending_qc

Phase 3: Quality Control Review

Reviewer accesses job through QC dashboard
Side-by-side video player with generated captions/audio descriptions
Inline VTT editor for making corrections
Timing adjustment tools for synchronization
Approve or reject with reviewer notes
If approved, job moves to translation phase

Phase 4: Translation and Localization

Automatic translation of approved English content
Support for standard translation and cultural transcreation
Available target languages: Spanish, French, German (expandable)
Translated VTT files stored per language

Phase 5: Audio Generation

Text-to-speech synthesis using ElevenLabs API
MP3 files generated for each audio description track
Language-specific voice selection
Audio files stored alongside VTT content

Phase 6: Final Review and Delivery

Final review by authorized reviewer
Asset validation to ensure all requested outputs present
Client notification of job completion
Signed URL generation for secure downloads

5. User Interface and Experience

5.1 Client Workflow

Dashboard:

Overview of all jobs with status indicators
Quick actions for creating new jobs
Real-time status updates via WebSocket
Notification system for job completion

Job Creation Process:

Video Upload: Drag-and-drop interface with progress tracking
Job Configuration:
- Descriptive title
- Source language selection
- Output format selection (captions VTT, audio description VTT, audio MP3)
- Target languages for translation
Processing Initiation: Automatic background processing begins
Confirmation: Success page with job tracking link

Job Monitoring:

Detailed status view with progress indicators
Processing history timeline
Real-time updates without page refresh
Error notifications with context

Content Download:

Secure download links for completed assets
Organized by language (en/, es/, fr/, de/)
File format options (VTT, MP3)
Source video access

5.2 Reviewer Workflow

Quality Control Dashboard:

Queue view of jobs pending review
Priority sorting by creation date
Job metadata preview
Quick status filtering

Review Interface:

Video Player: HTML5 player with custom controls
VTT Editor: Syntax-highlighted editor with validation
Side-by-Side View: Simultaneous video and text editing
Timing Tools: Bulk timing adjustment with offset controls
Review Controls: Approve/reject with mandatory notes

Advanced Features:

Keyboard shortcuts for efficient workflow (A=Approve, R=Reject, S=Save)
View mode switching (side-by-side, video-only, editor-only)
Real-time VTT validation and error highlighting
Unsaved changes warnings

Final Review Process:

Asset validation before completion
Final quality checks
Client notification triggering
Completion workflow

5.3 Administrator Interface

User Management:

Create users with role assignment
Password reset functionality
User activation/deactivation
Role-based permission enforcement

System Monitoring:

Health check dashboard with component status
Job processing statistics and metrics
Queue monitoring for background tasks
Performance analytics

Audit and Security:

Comprehensive audit logging
Security event monitoring
User activity tracking
System maintenance tools

6. Data Models and Storage

6.1 Job Data Structure

interface Job {
  id: string;                    // Unique job identifier
  client_id: string;            // Owner client ID
  title: string;                // Human-readable job name
  status: JobStatus;            // Current processing status
  
  source: {
    filename: string;           // Storage path
    original_filename: string;  // User's original filename
    gcs_uri: string;           // Google Cloud Storage URI
    duration_s: number;        // Video duration in seconds
    language: string;          // Source language code
  };
  
  requested_outputs: {
    captions_vtt: boolean;          // Closed captions requested
    audio_description_vtt: boolean; // Audio description script requested
    audio_description_mp3: boolean; // Audio voiceover requested
    languages: string[];            // Target languages
    transcreation: string[];        // Languages requiring cultural adaptation
  };
  
  outputs: {
    [language: string]: {
      captions_vtt_gcs?: string;      // VTT file location
      ad_vtt_gcs?: string;           // Audio description VTT location
      ad_mp3_gcs?: string;           // Audio MP3 file location
      origin: "translate" | "transcreate"; // Processing method
      qa_notes?: string;             // Quality assurance notes
    };
  };
  
  ai: {
    ingestion_json: object;     // Full AI response data
    confidence: number;         // AI confidence score (0-1)
  };
  
  review: {
    notes: string;              // Current reviewer notes
    reviewer_id?: string;       // Last reviewer ID
    history: ReviewHistoryItem[]; // Complete review history
  };
  
  created_at: Date;
  updated_at: Date;
  error?: ErrorInfo;            // Processing error details
}

6.2 User Data Structure

interface User {
  id: string;
  email: string;               // Unique login identifier
  hashed_password: string;     // Bcrypt hashed password
  full_name: string;           // Display name
  role: "client" | "reviewer" | "admin";
  is_active: boolean;          // Account status
  created_at: Date;
  updated_at: Date;
}

6.3 File Storage Organization

Google Cloud Storage Bucket Structure:

gs://accessible-video/
├── {jobId}/
│   ├── source.mp4                    # Original video
│   ├── en/
│   │   ├── captions.vtt             # English captions
│   │   ├── ad.vtt                   # English audio description
│   │   └── ad.mp3                   # English audio file
│   ├── es/
│   │   ├── captions.vtt             # Spanish captions
│   │   ├── ad.vtt                   # Spanish audio description
│   │   └── ad.mp3                   # Spanish audio file
│   └── [other languages]/
└── health_check_dummy               # System health verification

Security Features:

Signed URLs with 24-hour expiration
Role-based access control
Automatic cleanup on job deletion
Secure upload with content-type validation

7. API Design

7.1 Authentication Endpoints

POST /api/v1/auth/login
POST /api/v1/auth/refresh
POST /api/v1/auth/logout

7.2 Job Management Endpoints

POST   /api/v1/jobs              # Create new job
GET    /api/v1/jobs              # List jobs (filtered by role)
GET    /api/v1/jobs/{id}         # Get job details
DELETE /api/v1/jobs/{id}         # Delete job
DELETE /api/v1/jobs/bulk         # Bulk delete (admin only)

# Job Actions
POST   /api/v1/jobs/{id}/actions/approve_english
POST   /api/v1/jobs/{id}/actions/reject
POST   /api/v1/jobs/{id}/actions/complete
POST   /api/v1/jobs/{id}/actions/reject_final

# Content Management
GET    /api/v1/jobs/{id}/vtt                    # Get VTT content
PATCH  /api/v1/jobs/{id}/vtt                    # Update VTT content
POST   /api/v1/jobs/{id}/vtt/adjust-timing      # Adjust timing
GET    /api/v1/jobs/{id}/downloads              # Get download URLs
GET    /api/v1/jobs/{id}/validate               # Validate assets

7.3 Administrative Endpoints

# User Management
GET    /api/v1/admin/users
POST   /api/v1/admin/users
GET    /api/v1/admin/users/{id}
PATCH  /api/v1/admin/users/{id}
DELETE /api/v1/admin/users/{id}

# System Monitoring
GET    /api/v1/admin/stats
GET    /api/v1/admin/health/detailed
GET    /api/v1/admin/jobs/stats
GET    /api/v1/admin/audit-logs

7.4 File Management

GET    /api/v1/files/signed-url/{path}    # Generate signed download URL
POST   /api/v1/files/upload               # Direct file upload endpoint

7.5 Real-time Updates

WebSocket Endpoints:

/ws/jobs - General job status updates
/ws/jobs/{job_id} - Job-specific status updates

WebSocket Message Format:

{
  "job_id": "string",
  "status": "string",
  "updated_at": "ISO8601",
  "job_title": "string",
  "message": "string",
  "progress": "number"
}

8. AI Services Integration

8.1 Google Gemini 2.5 Pro Integration

Content Generation Capabilities:

Video content analysis and understanding
Automatic transcript generation
Closed caption creation with proper timing
Audio description generation for visual elements
Content confidence scoring

Processing Flow:

Video upload to Gemini Files API
Content generation using multimodal prompt
Structured JSON response parsing
Error handling and self-healing for invalid responses
Automatic file cleanup after processing

Quality Assurance:

VTT format validation
Timestamp accuracy verification
Content completeness checks
Fallback content generation for missing elements

8.2 Translation Services

Google Cloud Translate:

High-quality machine translation for standard content
Support for multiple target languages
VTT format preservation during translation
Batch processing for efficiency

Transcreation via Gemini:

Cultural adaptation for marketing content
Context-aware translation with brand guidelines
Maintained timing synchronization
Creative adaptation while preserving meaning

8.3 Text-to-Speech Integration

ElevenLabs TTS Service:

High-quality voice synthesis
Language-specific voice selection
MP3 output format
Proper pronunciation for accessibility terms

Audio Processing:

Per-cue synthesis for precise timing
Audio quality optimization
File format standardization
Integration with VTT timing

9. Quality Control Features

9.1 Review Workflow

Content Review Process:

Initial Review: AI-generated content assessment
Content Editing: Direct VTT file modification
Synchronization Check: Video timing validation
Quality Verification: Accessibility standards compliance
Final Approval: Content ready for translation

Review Tools:

Integrated video player with caption overlay
Syntax-highlighted VTT editor
Real-time content validation
Timing adjustment utilities
Review history tracking

9.2 Quality Metrics

AI Confidence Scoring:

Content generation confidence (0-100%)
Quality indicators for reviewer guidance
Threshold-based workflow routing

Review Analytics:

Processing time tracking
Reviewer performance metrics
Quality score trending
Error rate monitoring

10. Security and Compliance

10.1 Data Security

Authentication Security:

JWT token-based authentication
HttpOnly cookie refresh tokens
Automatic token rotation
Secure password hashing (bcrypt)

File Security:

Signed URL access control
Time-limited download permissions
Secure file upload validation
Automatic cleanup procedures

API Security:

CORS protection
Rate limiting
Input validation and sanitization
SQL injection prevention (NoSQL)

10.2 Privacy Protection

Data Handling:

Client data isolation
Role-based access enforcement
Audit trail maintenance
Secure data deletion

Content Protection:

Temporary file processing
Secure cloud storage
Access logging
Data retention policies

10.3 Audit and Compliance

Audit Logging:

User action tracking
System event logging
Security event monitoring
Performance metric collection

Compliance Features:

Data export capabilities
User consent management
Access control documentation
Security incident tracking

11. Performance and Scalability

11.1 System Performance

Backend Performance:

Async request handling with FastAPI
Background task processing via Celery
Database query optimization
Caching strategy with Redis

Frontend Performance:

React Query for data caching
Lazy loading of components
Optimized bundle splitting
Progressive web app features

11.2 Scalability Architecture

Horizontal Scaling:

Stateless API servers
Independent worker processes
Load balancing ready
Database connection pooling

Resource Optimization:

File compression and optimization
CDN integration ready
Memory-efficient processing
Garbage collection optimization

11.3 Monitoring and Observability

Health Monitoring:

Component health checks
Service dependency monitoring
Performance metric collection
Error rate tracking

Logging and Debugging:

Structured logging with correlation IDs
Error tracking and alerting
Performance profiling
Debug mode capabilities

12. Deployment and Infrastructure

12.1 Containerization

Docker Configuration:

Multi-stage builds for optimization
Health check integration
Environment-based configuration
Security-hardened images

12.2 Environment Configuration

Development Environment:

Local Docker Compose setup
Hot-reload development servers
Test database seeding
Mock external services

Production Environment:

Cloud-native deployment
SSL/TLS termination
Environment variable management
Secret management integration

12.3 Database Management

MongoDB Configuration:

Document schema validation
Index optimization
Replica set support
Backup and recovery procedures

Migration System:

Schema version tracking
Safe migration procedures
Rollback capabilities
Data integrity validation

13. Testing Strategy

13.1 Testing Levels

Unit Testing:

Service layer testing
Utility function testing
Component testing
Mock external dependencies

Integration Testing:

API endpoint testing
Database integration testing
File storage integration
Authentication flow testing

End-to-End Testing:

Complete user workflow testing
Cross-browser compatibility
Mobile responsiveness
Performance testing

13.2 Testing Tools

Backend Testing:

PyTest for unit and integration tests
Factory Boy for test data generation
Async test support
Mock external services

Frontend Testing:

Jest for unit testing
React Testing Library
Playwright for E2E testing
Visual regression testing

14. Error Handling and Recovery

14.1 Error Classification

User Errors:

Invalid file formats
Insufficient permissions
Validation failures
Authentication errors

System Errors:

External service failures
Database connection issues
File storage problems
Processing timeouts

Recovery Strategies:

Automatic retry mechanisms
Graceful degradation
User-friendly error messages
Administrative error resolution

14.2 Reliability Features

Fault Tolerance:

Circuit breaker patterns
Timeout configurations
Retry logic with exponential backoff
Fallback procedures

Data Integrity:

Transaction management
Consistent state handling
Backup and recovery
Data validation

15. Configuration and Customization

15.1 System Configuration

Application Settings:

Environment-specific configurations
Feature flag support
Service endpoint configuration
Security parameter tuning

Processing Configuration:

AI model parameters
Translation service options
File size limits
Processing timeouts

15.2 User Customization

Client Settings:

Language preferences
Notification preferences
Default job settings
Download preferences

Reviewer Settings:

Workflow preferences
Editor configurations
Keyboard shortcuts
Quality thresholds

16. Future Enhancements

16.1 Planned Features

Enhanced AI Capabilities:

Multi-modal content analysis
Improved accuracy metrics
Custom model training
Advanced quality scoring

Extended Language Support:

Additional target languages
Regional dialect support
Custom transcreation workflows
Cultural adaptation tools

Advanced Workflow Features:

Batch processing capabilities
Template-based job creation
Advanced approval workflows
Custom review stages

16.2 Integration Opportunities

Third-Party Integrations:

Content management systems
Video hosting platforms
Accessibility testing tools
Quality assurance services

API Extensions:

Webhook support for job events
Advanced reporting APIs
Bulk operation endpoints
Custom integration points

17. Conclusion

The Video Accessibility Processing Platform represents a comprehensive solution for automated video accessibility content generation. Built with modern web technologies and integrated with leading AI services, the platform provides an end-to-end workflow from video upload to final content delivery.

The system's architecture supports scalability, security, and reliability while maintaining a focus on user experience and content quality. The role-based access control ensures appropriate separation of concerns between content creators, quality reviewers, and system administrators.

With its robust API design, real-time updates, and comprehensive error handling, the platform serves as a professional-grade solution for organizations requiring high-quality accessibility content at scale.

This specification document serves as the comprehensive technical and functional guide for the Video Accessibility Processing Platform, detailing all implemented features, workflows, and system capabilities as of the current release.

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