Bài viết bên dưới được đăng bằng tiếng Anh. Mọi con số trong đó là con số do chính nhà cung cấp công bố, kèm ngày chúng tôi đọc được.
Both of these turn a script into a video of a presenter who does not exist. They overlap enough that most teams will only buy one.
What the table separates
Rows marked Editorial call are our judgment and carry the reasoning. The fact rows carry two published figures with the pages they came from, and you can check both in under a minute.
We have not compared output quality. Doing that honestly would mean generating the same script through both and having somebody who is not us judge the result, and we have not done it. What we can compare is what each vendor lets you produce before paying, which is the thing that decides which one you try first.
What is not in this comparison
Both entry prices now appear in the table, and they match: Synthesia's Starter and HeyGen's Creator both list $29 a month, and each page carries the USD figure in its data. The old note about neither entry price appearing is gone because HeyGen's pricing page stops being unreadable the moment you read its underlying data, which names the currency. The comparison no longer needs to send you to the vendor's page to learn what each charges before committing.
The language row changed direction. The previous version called this for HeyGen on the strength of its marketing, and the published counts do not support that call: Synthesia prints 160+ languages and voices across its plans and 70+ dubbing output languages on Basic through Creator, against a 30+ figure on HeyGen's free card. The row now says what the numbers say, and the editorial call is confined to what HeyGen markets harder.
The free tier story is now symmetric on shipping: both free outputs stop short of a deliverable, one with a watermark and one with a license term, and the evaluation row says so on both sides. Synthesia's ten minutes of watermarked video is an evaluation of the product itself; HeyGen's three clips are the same evaluation with a different ceiling.
The two reviews read the boundaries in full: the Synthesia review weighs ten minutes of finished video against a watermark, and the HeyGen review reads the ownership sentence next to the license HeyGen takes. The profiles carry the same figures behind each column: Synthesia and HeyGen.