Gemini Omni 1.1 Flash vs Veo 3.1: which video API should you call?

Gemini Omni 1.1 Flash vs. Veo 3.1: Which Video API Should You Use?

Google now ships two generative video models behind the same API key, but they are not versions of the same product. Veo 3.1 is the cinematic renderer with native audio. Gemini Omni 1.1 Flash, generally available since August 27, 2026, is the conversational model you can edit across turns.

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Choosing between them comes down to three questions:

• Do you need sound?
• Do you need to iterate after viewing a clip?
• How long must the final video be?

Here’s how each model answers those requirements.

Comparison table

Capability	Gemini Omni 1.1 Flash	Veo 3.1
Model ID	gemini-omni-1.1-flash	veo-3.1-generate-preview plus fast and lite variants
API surface	Interactions API (/v1beta/interactions)	generateContent, long-running operation
Native audio	No	Yes, always on
Base clip length	10 seconds	4, 6, or 8 seconds
Maximum length via extension	40 seconds, in 10-second steps	148 seconds, 7 seconds at a time, up to 20 extensions
Context read when extending	Up to 10 seconds of prior footage	Not stated
Conversational editing	Yes, via previous_interaction_id	No
First and last frame	Yes	Yes, via lastFrame
Reference media	Up to three video clips of three seconds each	Up to three reference images
Resolutions	360p, 720p, 1080p, 4K	720p, 1080p, 4K; 720p only when extending
Aspect ratios	16:9, 9:16	16:9, 9:16
720p cost per second	Approximately $0.10	$0.40 standard, $0.10 fast, $0.05 lite
Free tier	No	No
Watermark	SynthID	SynthID

When Gemini Omni 1.1 Flash is the better fit

You need conversational editing

This is Omni’s main differentiator. It runs on the Interactions API, so you can generate a clip, inspect it, and send a follow-up request that edits the result:

res1 = client.interactions.create(
    model="gemini-omni-1.1-flash",
    input="A woman playing violin outdoors.",
)

res2 = client.interactions.create(
    model="gemini-omni-1.1-flash",
    previous_interaction_id=res1.id,
    input="Make the violin invisible.",
)

You don’t need to re-upload the clip or describe the entire scene again. Veo has no equivalent workflow: each request is a fresh generation, so every change requires a new prompt and another generation attempt.

You want inexpensive drafts

Omni’s 360p tier generates up to 60% faster and costs one-third as much as its 720p tier. Veo’s lowest resolution is 720p.

If you are twelve attempts into refining a prompt, the savings add up. See the pricing breakdown for the numbers.

You are providing video references

Omni accepts up to three reference clips, each three seconds long, and maps their movement onto the new scene. Veo accepts reference images instead.

When you need to match motion or maintain a character across shots, motion references can provide information that still images cannot.

You need temporal consistency during extension

Omni reads up to 10 seconds of prior footage before continuing. The preview model used a single final second. The scene extension guide explains how this affects longer sequences.

When Veo 3.1 is the better fit

You need audio

Veo generates native audio with the video. Omni’s documentation covers video output but does not describe audio generation for reference clips.

If the deliverable includes sound, this requirement determines the choice. The Veo 3.1 API guide covers the integration.

You need more than 40 seconds

Veo extends clips by seven seconds at a time, up to 20 times, for a maximum length of 148 seconds. Omni is capped at 40 seconds.

There is an important limitation: extended Veo output is 720p only. A long clip and a 4K clip therefore require different workflows.

You need the lowest possible cost per second

Veo 3.1 Lite costs $0.05 per second at 720p—half Omni’s rate. It does not support 4K.

For high-volume, low-stakes generation, Lite is the lowest-cost option across both model families.

You need a shorter base clip

Veo supports four-second and six-second generations. Omni generates 10-second clips.

If you need a four-second cut, Veo bills for four seconds while Omni bills for the full 10 seconds.

The decision in four lines

• Need sound? Use Veo 3.1.
• Need more than 40 seconds? Use Veo 3.1.
• Need conversational editing or inexpensive drafts? Use Gemini Omni 1.1 Flash.
• Need the cheapest possible second? Use Veo 3.1 Lite.

Many production pipelines use both models: Omni for exploration and conversational shot refinement, then Veo for the final take with audio. Both models use the same API key, so there is no additional setup cost for running both.

Two integrations, not one

The models use structurally different endpoints:

• Omni: Send a POST request to /v1beta/interactions with the model in the request body. Video is returned inline as base64 unless the file exceeds 4 MB, in which case the response contains a URI.
• Veo: Start a long-running operation and poll for completion. Generated files remain on Google’s servers for two days before removal.

This matters if you plan to swap models later. Code written for one model cannot be migrated to the other by changing only the model string. An abstraction layer must support both a polled operation and two possible response shapes.

The Omni API walkthrough covers response handling.

Before building a production integration, create saved requests for both models. Set up one request per model in Apidog, store the API key in an environment variable, assert the response shape, and increase the timeout beyond the defaults.

When comparing output quality, running the same prompt through two saved requests is faster and more repeatable than rewriting curl commands from memory.

FAQ

Is Gemini Omni a replacement for Veo?

No. Google ships both models, and Veo 3.1 is not deprecated. They are different tools that both generate video.

Which model is cheaper?

At 720p, Omni at approximately $0.10 per second and Veo 3.1 Fast at $0.10 per second cost about the same. Veo 3.1 Lite is cheaper at $0.05 per second. Standard Veo 3.1 is the most expensive at $0.40 per second.

Can either model generate dialogue?

Veo generates native audio. Omni’s video output does not cover audio generation, and Omni cannot add dialogue when extending an uploaded video.

Do both models watermark their output?

Yes. Both apply SynthID, which is invisible to viewers and detectable programmatically.

What about Sora or other video APIs?

Different providers offer different trade-offs. OpenAI Sora 2 and Seedance 1.0 are worth evaluating if you are looking beyond Google’s lineup.

Which model should you start with?

If you are prototyping and do not need sound, start with Omni at 360p. It is the least expensive way to test whether generated video solves your problem. Download Apidog and save the first request so you can repeat the comparison.

The short version: Veo renders, while Omni converses. Google’s video generation documentation covers both models. Choose the model per job rather than standardizing on one for the entire team.