If you found the InfiniteTalk API through a provider listing and you want lip-synced talking video without standing up GPUs or committing to an open-weights deployment, here is the honest comparison. InfiniteTalk and hiapi's heygen-avatar-v solve overlapping problems from opposite directions: InfiniteTalk is an open-weights, audio-driven video model you run yourself or reach through a third-party host, while heygen-avatar-v is a managed API that turns a script or an audio track into a lip-synced presenter video for a flat $0.15 per second. They are not drop-in equivalents — and the single place they diverge is exactly where you should make the call. Two real heygen-avatar-v renders are below.
What "InfiniteTalk API" actually means
InfiniteTalk is an open-source, audio-driven video model released in 2025. Its signature trick is sparse-frame video dubbing: give it an existing video plus an audio track, and it regenerates the clip with new lip-sync while preserving the original person, background, and camera motion — at effectively unlimited length. It also runs as an image-plus-audio-to-video model. As of this writing it targets 480P and 720P output.
Because the weights are open, "the InfiniteTalk API" is not a single first-party endpoint. It is either your own GPU deployment or a third-party host — WaveSpeed and similar resellers — that wraps the model and bills you for it. That openness is the appeal: maximum control, the ability to fine-tune, and no per-second vendor markup if you own the hardware. It is also the operating cost: you maintain the model, the GPUs, and the pipeline, or you accept a reseller's rate card and queue.
Where heygen-avatar-v is a genuine alternative — and where it isn't
Be clear about the boundary first, because it is the decision:
- heygen-avatar-v generates from a preset avatar — 497 presenters and 102 voices. It does not re-dub a specific clip you already have. If your core job is "take this footage of a real person and re-sync their mouth to new audio," that is InfiniteTalk's video-to-video territory, and heygen-avatar-v is not a substitute for it.
- Where it is a strong alternative: if what you actually need is a lip-synced talking video from a script or an audio track — an explainer, a lesson, a product or UGC-style ad — heygen-avatar-v produces exactly that, as a managed API, with no model to host and no reseller in the path.
Most teams typing "InfiniteTalk API" into a search bar are in the second camp. They want the output — a talking clip driven by audio or text — not the obligation of running a diffusion model in production. That is the gap heygen-avatar-v fills. If you specifically need your own recorded footage re-synced to fresh narration, stay with InfiniteTalk's dubbing workflow; nothing here replaces it.
What heygen-avatar-v actually does
One POST https://api.hiapi.ai/v1/tasks call returns a lip-synced avatar video. There are two ways to drive it:
- Script-driven — pass
avatarplusprompt(up to 5,000 characters) and an optionalvoice; the API speaks the script and syncs the mouth. - Audio-driven — pass
avatarplusaudio_url(up to 600 seconds, 32 MiB) and omitprompt/voice; the avatar lip-syncs to a recording you already have. This is the mode that maps cleanly onto an audio-first InfiniteTalk workflow.
Output controls cover resolution (720p / 1080p / 4k), six aspect ratios including 9:16, output_format (mp4 / webm), caption: true for a sidecar SRT file, plus fit, remove_background, and a background override. Pricing is a flat $0.15 per second of output — no resolution surcharge, settled to the actual seconds rendered, with failed tasks refunded.
Script to presenter
HeyGen Avatar V is live on HiAPI. Create polished presenter videos from a script or audio, with natural motion and captions. Launch offer: twenty percent off.
Rendered with avatar: "Abigail Sofa Front" and voice: "Derya - Lifelike - Excited" at 1280×720 (the 720p web version). The whole clip came from that one script — no footage shot, no portrait uploaded.
A casual, direct-to-camera ad take
A second heygen-avatar-v render, this one a loose UGC-style product hook — the kind of short, lifestyle-framed spot teams reach for InfiniteTalk-class tools to produce. Same task API, a different preset avatar and setting. Honest caveat from testing: the backdrop ships with the chosen avatar, and a background override does not always replace a filmed scene, so test your avatar-plus-background combination on a short clip before a production run.
InfiniteTalk vs. heygen-avatar-v: pick by how you want to run it
| InfiniteTalk (open weights) | heygen-avatar-v (hiapi) | |
|---|---|---|
| How you run it | Self-host on your GPUs, or a third-party reseller | Managed API, one hiapi key |
| Core strength | Re-dub an existing video; unlimited length | Preset-avatar talking video from script or audio |
| Driving input | Audio (+ a source video or image) | Script (prompt) or audio_url |
| Your own person on screen | Yes — video-to-video dubbing | No — curated presets (use Avatar IV for one photo) |
| Output | 480P / 720P | 720p / 1080p / 4k, six aspect ratios, mp4/webm, SRT captions |
| Cost model | Your GPU time, or a reseller's rate | Flat $0.15/sec of output, failed tasks refunded |
| Ops burden | A model and infra you maintain | None — POST /v1/tasks |
The axis that matters is the first row. InfiniteTalk hands you the model; heygen-avatar-v hands you the result. If re-dubbing your own footage or unlimited length is the requirement, run InfiniteTalk. If "a talking video from a script or audio, billed per second, behind one key" is the requirement, heygen-avatar-v gets you there without touching a GPU.
A working request
The closest analog to an audio-first InfiniteTalk job is heygen-avatar-v's audio-driven mode — your recording in, a lip-synced avatar out:
{
"model": "heygen-avatar-v",
"input": {
"avatar": "Brandon Office Sitting Front",
"audio_url": "https://example.com/your-recording.mp3"
}
}
Prefer to drive it from text, vertical, with burned-in-ready captions? Swap audio_url for a script:
curl -X POST https://api.hiapi.ai/v1/tasks \
-H "Authorization: Bearer $HIAPI_API_KEY" \
-H "Content-Type: application/json" \
-d '{
"model": "heygen-avatar-v",
"input": {
"avatar": "Riley Casual Front",
"prompt": "New drop just landed. Swipe up and shop now!",
"voice": "Charming Charles - Friendly",
"aspect_ratio": "9:16",
"resolution": "1080p",
"caption": true,
"output_format": "mp4"
}
}'
Save data.taskId, poll GET /v1/tasks/{taskId} until status is success, then download each item in output[] (the video, plus a caption SRT when enabled) before its expireAt. It is the same task-based pattern as every other video model on the platform — see the Unified Async API quickstart for the shared request/response shape, and the heygen-avatar-v model page for the full avatar and voice preset lists.
FAQ
Can heygen-avatar-v re-dub a video I already have? No. That holistic, identity-preserving dubbing of existing footage is InfiniteTalk's specialty. heygen-avatar-v generates from curated preset avatars. If you only need a single still portrait animated, Avatar IV is the photo-driven sibling; neither is a video-to-video dubber.
Can I drive it with my own audio instead of a script?
Yes. Pass audio_url (up to 600 seconds, 32 MiB) and omit prompt and voice. The avatar lip-syncs directly to your recording.
What does it cost? A flat $0.15 per second of output, identical across 720p, 1080p, and 4k, settled to the actual seconds rendered. Failed tasks are refunded.
Which resolutions and aspect ratios are available?
720p, 1080p, and 4k, with six aspect ratios: 16:9, 9:16, 4:5, 5:4, 1:1, and auto.
Do I have to host or maintain anything? No. heygen-avatar-v is a managed API behind your existing hiapi key — no weights, no GPUs, no separate signup. That is the main trade versus running InfiniteTalk yourself.
Get started
If your real goal is lip-synced talking video from a script or an audio file — not self-hosting a model — heygen-avatar-v is the shorter path. Pick a presenter and a voice on the heygen-avatar-v model page, try a one-line script, then wire the task API into your pipeline. For a focused social walkthrough, see turning a script into a talking-head short; if you are also weighing seat-based or other hosted avatar tools, the Synthesia and Hedra comparisons cover those trade-offs.
