AI Digital Human Creation SOP: A Repeatable Workflow from Script to Final Cut

Digital humans are no longer novel, but few people can turn them into stable output. Two common ways to die: one, fire up HeyGen, click twice, and ship it-only to get lip-sync drift and stiff expressions, viewers scrolling away in three seconds. Two, chase hyper-realistic from day one, obsessing over skin-pore rendering, and fail to produce a single clip in a month.

The problem isn't the tool, it's the workflow. Digital human production is a chain of six things: pick the right tool, write a solid script, define the avatar, generate voiceover, post-process, and publish compliantly. Each step has pitfalls, but each also has a repeatable fix. This SOP breaks those six steps down, with runnable prompt templates and five real pitfalls. This is a representative workflow, not a single-tool hands-on test; the flow is generic, and specific features are subject to each tool's official site-these tools change pricing and revamp often, so check the official site before you start.

One-line definition: a digital human is not "pick an avatar and hit generate." It's a pipeline where the script drives the avatar, the avatar drives the voiceover, and the voiceover drives the lip-sync. Script quality sets the ceiling; the tool only sets the floor.

1. Pick the Tool by Use Case: Decide Who You're Showing To First

90% of people stall at step one because they start building without clarifying the use case. Product walkthroughs for sales, onboarding for HR, talking-head short videos, e-commerce live-stream clips-these four scenarios demand completely different things from a digital human: explainer content needs clear information and decent lip-sync; training needs stable multilingual support; talking-head needs emotion and naturalness; live clips need to not fall apart over long durations.

Frame the tool by use case first, never the other way around. The table below is a representative positioning of mainstream tools in 2026 (compiled from public comparisons on comparegen.ai, heygen.com/blog, colossyan.com, etc.; pricing subject to official sites):

Three selection questions: 1) What's the budget (per-minute billing or subscription)? 2) Do you need multilingual? 3) Do you need to clone your own likeness? The first two decide whether you go with overseas SaaS or a domestic tool; the third decides whether you pick a preset avatar or a custom clone. Tight budget and just validating an idea-D-ID starts fastest. For stable commercial output, HeyGen or Synthesia are safe bets. For Chinese scenarios, try Tencent Zhiying or Guiji Intelligent first.

Pitfall preview: don't buy based on the official demo alone. Demos are hand-picked best cases-run a real script yourself before paying.

2. Write the Talking-Head Script: The Soul of a Digital Human Is Text

Many assume the hard part of digital humans is the avatar. Actually, the script sets the ceiling. No matter how realistic the avatar, an empty script still loses viewers. The difference between a digital human script and a live-action script: a digital human can't improvise-every line must be written down, and pauses, tone, and emphasis are all text-driven.

Use a three-part structure: hook, body, close. The hook grabs attention in three seconds, the body explains one thing clearly (don't overstuff), and the close gives a call to action. Word count maps to speaking rate: Chinese talking-head runs about 220-260 characters per minute, English about 130-150 words. A 60-second clip should keep the Chinese script at 220-260 characters.

Reusable script-generation prompt (feed to an LLM):

You are a senior talking-head copywriter. Write a 60-second digital human script for [product/topic].
Requirements:
1. Three-part structure: 3-second hook (question or counter-intuitive claim) + body (explain 1 core selling point with 1 concrete example) + close (1 call to action);
2. English, 130-150 words, conversational, short sentences, avoid written long sentences;
3. Annotate each segment with estimated duration and tone (calm / excited / emphasis);
4. No filler like "as everyone knows" or "in conclusion."
Output format: [duration|tone] text

After getting the script, read it aloud yourself-shorten anything that trips your tongue. Digital humans don't breathe, but listeners tire, so split long sentences into two short ones. For multilingual versions, don't machine-translate directly-have the LLM rewrite in the target language's spoken idiom (not translate), or the English version will carry Chinese-style syntax and sound awkward when D-ID or HeyGen's TTS reads it.

3. Pick or Customize the Avatar: Preset Avatar or Clone Yourself

Two paths for the avatar: use a platform preset avatar, or clone yourself or a model.

Preset avatars are fastest. HeyGen, Synthesia, and Tencent Zhiying all ship with dozens to hundreds of avatars, filterable by gender, age, profession, and outfit-pick one and use it directly. The upside is low compliance risk (platform-licensed); the downside is homogenization-you may share an avatar with another company. Good for the validation stage and tight budgets.

Cloning your own likeness (HeyGen's Instant Avatar, D-ID's Custom Avatar, Guiji Intelligent's clone) requires recording 1-2 minutes of footage: frontal, even lighting, solid-color background, reading specified text. Upload it, and the platform trains a model in minutes to hours. This is the standard route for commercial films, with naturalness far above presets. But mind the licensing-see Pitfall 1.

Custom avatar recording tips:

1. Environment: solid-color background (green screen or white wall), frontal soft light (no overhead light-it shadows the eye sockets), clean audio (no echo);
2. Content: the platform's calibration text must be read in full-skipping words biases the lip-sync model;
3. Wardrobe: no fine stripes (moiré), no reflective accessories, solid-color collared shirt is safest;
4. Duration: follow platform requirements, usually 1-2 minutes-don't cut it short to save time.

Pitfall preview: only clone your own likeness or a model with signed authorization. Training on internet images or someone else's likeness gets your account banned, and commercial use may invite portrait-rights lawsuits.

4. Generation and Voiceover: Lock the Voice First, Then Drive the Lips

Voiceover and lip-sync are coupled: pick or synthesize the voice first, then use that audio to drive the avatar's lip-sync. Reverse the order (generate video first, then dub) and lip-sync will inevitably drift.

Three voice paths: 1) platform built-in voices (HeyGen, Synthesia both have dozens of multilingual voices); 2) clone your own voice (requires a sample-HeyGen Voice Cloning, ElevenLabs both support this); 3) external TTS-generated audio imported (generate with Doubao or CapCut text-to-speech, import into tools like D-ID that support "audio-driven" input).

Multilingual voice is the disaster zone (see Pitfall 3). HeyGen and Synthesia keep the same voice across languages, which is relatively natural; external TTS often changes voice across languages. For multilingual releases, prefer the platform's native multilingual voices-don't cobble together external TTS.

Generation tips:

1. Paste the script into the tool in segments, one segment per shot-don't dump the whole thing in (long text tends to drift mid-way in lip-sync);
2. Pick voice and language, preview the audio (listen for pace and phrasing-regenerate with adjusted speed if unsatisfied);
3. After confirming the audio, generate the video-keep each segment 30-60 seconds, and for long videos generate per segment then stitch (see Pitfall 4);
4. After generation, check lip-sync and expression segment by segment-regenerate any obviously off segment; don't count on fixing lip-sync in post (prohibitively expensive).

Reusable multilingual script-adaptation prompt:

Rewrite the Chinese talking-head script below into [English/Japanese].
Requirements:
1. Not a literal translation-rewrite in the target language's spoken idiom, keep it conversational with short sentences;
2. Preserve the meaning and three-part structure (hook-body-close);
3. Match the Chinese version's duration (about 60 seconds, English 130-150 words);
4. Avoid culturally awkward phrasing, localize examples.
Output: the rewritten script only, no explanation.

5. Post-Processing: Subtitles, Editing, and Compliance

A digital human's raw video usually needs three post steps: subtitles, editing and stitching, and compliance labeling.

Subtitles: use CapCut or Whisper to auto-generate subtitles, then proofread once (proper nouns and numbers are always wrong). Keep subtitle styling simple-white text with black outline or black text on white is clearest, font size about 1/15 of frame width. For bilingual subtitles, two lines-Chinese on top, English below.

Editing: use cross-dissolve between stitched segments, not hard cuts (digital humans jump more jarringly on hard cuts than real humans). Insert product images or key-info cards between shots to break monotony. Keep background music below -15dB relative to the voice-don't let it drown the speaker.

Compliance labeling: the most easily skipped but most critical step. Multiple jurisdictions require explicit labeling of AI-generated content (see Pitfall 5). Add an "AI-generated" watermark or corner bug on the video, note "this video contains AI-generated content" in the description, and always check the platform's "AI-generated" tag if it has one.

Pitfall preview: compliance labeling isn't an "optional embellishment"-it's a hard requirement. Missing it may get the video taken down, and commercial use may violate local AI-content regulations.

6. Publishing: Platform Adaptation and Version Management

Before publishing, export to platform specs: vertical 9:16 (TikTok/Reels/Video Accounts), horizontal 16:9 (YouTube/Bilibili), square 1:1 (some feeds). Resolution at least 1080P, bitrate per platform recommendation. Distinguish multilingual versions of the same script by filename (e.g., intro_zh.mp4, intro_en.mp4)-don't overwrite.

Three things at publish time: 1) write the topic and key points in the description (SEO-friendly); 2) check the AI-content tag (every platform has one); 3) track the first 24 hours of data-if completion rate is below 30%, the hook likely failed-go back and rewrite the first 3 seconds.

Pitfall Quick Reference

Pitfall 1 Avatar licensing landmines. Only clone your own likeness or a model with signed written authorization. Training on internet images, celebrity photos, or someone else's likeness gets your account banned at minimum, and may invite portrait-rights lawsuits. For commercial projects, keep authorization documents on file.

Pitfall 2 Lip-sync drift. Root cause: reversed order of voiceover and video generation, or mid-segment drift on long text. Fix: lock audio first, then generate video; keep segments 30-60 seconds; split long videos into segments. Don't count on fixing lip-sync in post-it costs more than regenerating.

Pitfall 3 Multilingual voice changes. External TTS often switches voice across languages-the same digital human speaks as a woman in Chinese and a man in English. Fix: prefer platform-native multilingual voices (HeyGen, Synthesia keep the same voice across languages), or clone a separate voice per language.

Pitfall 4 Long-video cost blowup. These tools mostly bill per minute or per credit-a 10-minute video can cost 10x a 1-minute one. Fix: split long content into short segments, generate each independently and stitch; preset avatars are cheaper than clones-use presets for validation.

Pitfall 5 Missing compliance labels. Multiple jurisdictions require explicit labeling of AI-generated content. Add an "AI-generated" corner bug on the video, note it in the description, and check platform tags. Commercial use is especially strict-run through a compliance checklist before publishing.

FAQ

Q1: Can digital humans fully replace live-action on-camera presence? Not yet. Digital humans suit "information delivery" scenarios like talking-head, explainers, and training-emotion and improvisation still lag behind real humans. For brand flagship films and emotional storytelling, live action works better. A digital human is a cost-reduction tool, not a replacement.

Q2: How much does it cost to clone my own likeness and voice? Check the official site for current pricing. Representative ranges: HeyGen's Instant Avatar and Voice Cloning typically require a Creator-or-above subscription; D-ID has a lower barrier, good for small-budget validation; domestic options like Guiji Intelligent and Tencent Zhiying bill per minute or by package. Pricing changes often-check the official site before starting.

Q3: Which tool is best for multilingual? Synthesia and HeyGen have the broadest multilingual coverage (dozens of languages, same voice), good for globalizing enterprise training. D-ID has solid multilingual support but weaker voice consistency than those two. For Chinese-first content, pick Tencent Zhiying or Guiji Intelligent. Specific language lists are subject to each tool's official site.

Q4: Will digital human videos get throttled by platforms? It depends on platform policy and whether they're labeled. Most major platforms don't throttle explicitly-labeled AI content, but unlabeled or disguised-as-real content may be demoted. TikTok/Reels, Video Accounts, and YouTube all have AI-content tags-always check them when publishing.

Q5: What's the shortest path for a first-timer with zero experience? Sign up for D-ID or Tencent Zhiying (low barrier, free trials available), use a preset avatar plus built-in voice, and produce one 30-second explainer video end to end. Have an LLM write the script using the prompt above. Run the full pipeline once before considering likeness cloning and multilingual.

References

• HeyGen official site and pricing
• D-ID official site
• Synthesia official site
• Colossyan official site
• DeepBrain AI official site
• Tencent Zhiying
• AI digital human tools comparison (comparegen.ai)
• Workflow and features per each tool's official docs (2026-08, subject to real-time official site)