HeyGen Avatar IV

Positioning Overview

heygen-avatar-iv is a talking-avatar video model offered by HeyGen and called through the unified HiAPI.ai interface. Developers upload a single frontal face photo and provide either a script text or an audio clip to generate a talking video with lip sync, facial expressions, and gestures. It supports 720p and 1080p output as well as multiple aspect ratios, making it suitable for developers and content teams that need to quickly produce digital spokespeople or character narration materials.

Key Highlights

• Drive a full talking video with a single photo—Just one frontal face photo plus a script or audio yields a finished clip without filming or building 3D assets.
• Expressions and gestures move with the voice—The output goes beyond lip alignment: facial expressions and head motions change naturally with the speech, approaching the look of real-person delivery.
• Dual input via script text and audio—You can either fill in a script and choose a voice, or pass in an HTTPS audio file for lip sync, fitting existing dubbing workflows.
• Configurable aspect ratio and background—Multiple ratios such as 16:9, 9:16, and 1:1 are available, and solid-color or image backgrounds can be specified to fill the frame.

Capabilities

Generate talking video from a photo: Pass in one frontal face photo to generate a talking video; the output is a video file that can be used directly as a finished clip or for further editing.

Script to speech driving lip movement: Fill in script text and specify a built-in voice; the model synthesizes speech and drives the avatar to talk, with each script up to 5000 characters.

Audio lip sync: Pass in an HTTPS audio link to make the photo speak according to the audio's lip movements; each audio clip can be up to 600 seconds, and in this case the script and voice parameters do not take effect.

Output specification control: Choose 720p or 1080p resolution and set a ratio of 16:9, 9:16, 4:5, 5:4, 1:1, or follow the original image, fitting landscape, portrait, and square publishing placements.

Frame background fill: When the output ratio differs from the photo ratio, solid-color or image backgrounds can fill the blank areas to avoid empty edges in the frame.

Use Cases

• Marketing teams producing digital spokesperson videos—Generate talking-head videos from product scripts and brand character photos for websites, ad placements, and social media, with no need to schedule real people on camera.
• Training departments generating course explanation materials—Turn course handouts into scripts and batch-generate explanation videos with a consistent persona for embedding into learning platforms or courseware.
• Short-video creators producing vertical talking-head clips—Choose a 9:16 ratio and a selected voice to generate vertical talking-head material for direct use in short-video platform content updates.
• Multilingual content adaptation for existing dubbing—Pass in existing dubbing audio for lip sync and pair it with a photo to generate talking-head footage in the corresponding language for content localization.

Limitations and Selection Advice

The input photo must be a clear, frontal human face; profile views, occlusions, or group photos will noticeably affect results, and generation quality depends heavily on the source image. The output is a video rather than a pure text finished product, so a script or audio must be prepared in advance. A single audio clip is capped at 600 seconds and a script at 5000 characters; overly long content must be generated in segments. If you only need preset avatar portraits or real-person digital doubles, you should choose the corresponding other model routes.