## TL;DR
AI generates humans that don't exist -- digital avatars delivering corporate training at scale, virtual influencers with millions of followers, and AI-de-aged actors on screen. The synthetic media industry spans enterprise video, social media marketing, and entertainment, raising profound questions about authenticity, consent, and disclosure.

## Core Explanation
Digital human pipeline: (1) Face synthesis -- StyleGAN/Diffusion models generate photorealistic faces. For custom avatars: capture short video of real person, fine-tune model; (2) Voice -- neural TTS (ElevenLabs, Azure) provides realistic speech; (3) Lip-sync -- Wav2Lip auto-generates viseme sequences matching audio. Synchronizes mouth movements from speech; (4) Body animation -- 2D/3D pose estimation + gesture generation. Subtle movements (eye blinks, head tilts, hand gestures) prevent "uncanny valley" stillness; (5) Rendering -- real-time (for interactive) or offline (for pre-recorded). Enterprise platforms: Synthesia, Hour One, HeyGen.

## Detailed Analysis
Synthesia: web platform -- choose avatar (140+ stock or custom), type script, select voice, generate video in minutes. Enterprise use: onboarding, compliance training, product demos. $90M Series C at $1B (2023). D-ID: "talking head" animation from single photo. API integrated into chatbot platforms. Virtual influencers: Lil Miquela (created 2016, 2.8M followers) blurs line between real and virtual. Brand partnerships: Prada, Calvin Klein, Samsung. Ethical framework: disclosure labels (Meta 2024 requires AI-generated content labeling), consent (living persons must consent to digital replication), and posthumous rights (actors' estates controlling AI-recreated performances). EU AI Act (2026 enforcement): mandates transparency -- AI-generated content must be labeled as such. California AB 730/AB 602 prohibits non-consensual deepfake creation. Key challenge: the uncanny valley -- as digital humans approach photorealism, subtle imperfections become disturbing. The most successful digital humans (Lil Miquela) embrace a stylized aesthetic rather than aiming for perfect realism.