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minimaxir • today at 12:02 AM • 3 replies • view on HN

Using the grid trick for animations to generate the individual frames has been around for awhile and not specific to ChatGPT: I'm surprised it took this long for one of the official providers to make it explicit. However, adherence between frames is generally tricky, and even in the examples there is a lot of noise between frames although that could be due to compression.

SVG support is interesting but I suspect shenanigans are afoot since that's not how image generation models work, and it would likely strip any SynthID watermarks. It's possible OpenAI has pipelined a raster-to-vector tool that does the conversion automatically. (I developed a similar pipeline and it works extremely well; I'll open source it at some point)

EDIT: Per documentation, there is an explicit `output_format: "svg"`, and I am indeed correct there is raster-to-vector in play:

> The API creates a reference image and uses it to produce the SVG. The quality setting controls that reference image. Decode data[0].b64_json as base64 and save the resulting UTF-8 XML bytes with a .svg extension.

OpenAI claims 50% faster generation with Images 2.6 but curiously price is the same as Image 2.5.


Replies

vunderba • today at 2:38 AM

From what I can tell after some preliminary testing, you have to pass an additional large language model to the OpenAI API when generating SVGs.

I couldn't find this requirement in the documentation, but if you don't pass one in, you get this error:

  400 {"message": "SVG generation requires 'svg.model'.",
     "param": "svg.model", "code": "missing_required_parameter"}

I tried it with Sunburst with both gpt-5.5 and gpt-5.6-sol, and the results were nothing spectacular. It’s something you could already do in the ChatGPT interface by asking it to convert an existing image to an equivalent SVG.

https://imgpb.com/bkUrc

Recraft is probably the only group I know of that had a native text-to-SVG generator pretty early on, but since it’s a closed model, I’m not familiar with what they were doing under the hood technically.

https://fal.ai/models/fal-ai/recraft/v4/pro/text-to-vector

bizer • today at 2:25 AM

Image 2.6 costs more tokens for generating low and medium quality images, so it ends up being a bit more expensive. Could refer to https://developers.openai.com/api/docs/guides/image-generati...

padolsey • today at 2:36 AM

Yeh using sprites to make frames consistent (kinda tilting latent space towards a character consistency, zero-shot ~LoRA hack?) is old-school. I did this 3 years ago. https://j11y.io/dance/