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Model infoModelsSnapshot: 15 Oct 2026

Hume AI / Expression Measurement

Expression Measurement Video

Measures perceived facial expression and visible attributes from JPEG images and live video frames.

restrictedClosed weightsExpression analysis
Official documentation (opens in a new tab)Reviewed 13 Oct 2026
8 of 21 specification fields collected
Measured expressions48 expressions · 27 descriptionsSee specification notes below
Face limits2 measured · up to 32 detectedSee specification notes below
Input billingNot collectedHume API
Output billingNot collectedNo inferred price

Specifications

Provider-documented facts. “Not collected” means we have not verified that field yet, not that the feature is unsupported.

Context / input limit
Not collected
Maximum output
Not collected
Output modalities
Expression scoresSource for Output modalities (opens in a new tab)
Reasoning
Not collected
Tool calling
Not collected
Structured output
Not collected
Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Release date
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
Not collected
Context caching
Not collected
Expression labels
48 expressions · 27 descriptionsSource for Expression labels (opens in a new tab)

Only scores passing each array’s cutoff are returned. Video also returns bounding boxes for detected faces.

What scores mean
Scores describe perceived expression, not direct knowledge of a person’s feelings. Independent probabilities do not sum to one and should not be compared across names. An empty array is valid.Source for What scores mean (opens in a new tab)
Usage metering
Each image or accepted video frame counts as one third of a billable second, with a 10-second minimum per billed run. Face count does not set billed duration. Numeric rates require verification.Source for Usage metering (opens in a new tab)
Image input limits
JPEG only; up to 8,294,400 pixels per image. Uploaded image at most 2 MB; total multipart upload at most 25 MB.Source for Image input limits (opens in a new tab)
Face detection limits
2 measured · up to 32 detectedSource for Face detection limits (opens in a new tab)

Measures the largest faces first. Default detection threshold 0.9 and minimum face size 60 pixels. Contact support to increase measured faces.

Access & pricing

Prices belong to an endpoint and billing tier. A provider listing does not guarantee access for every account or region.

API model ID
Not collected

Dedicated service route; no checkpoint selector is documented.

Access
Limited release. Contact Hume for access and use an API key or access token.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
https://api.cloud.hume.ai/v1/expression/video/fileSource for API endpoint URL (opens in a new tab)
Usage metering
Each image or accepted video frame counts as one third of a billable second, with a 10-second minimum per billed run. Face count does not set billed duration. Numeric rates require verification.Source for Usage metering (opens in a new tab)

Endpoint pricing has not been collected. Check the provider for applicable rates.

Data & enterprise terms

Retention, training use, regional processing and enterprise terms have not been summarized for this endpoint.

API model ID
Not collected

Dedicated service route; no checkpoint selector is documented.

Access
Limited release. Contact Hume for access and use an API key or access token.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
wss://api.cloud.hume.ai/v1/expression/video/realtimeSource for API endpoint URL (opens in a new tab)
Usage metering
Each image or accepted video frame counts as one third of a billable second, with a 10-second minimum per billed run. Face count does not set billed duration. Numeric rates require verification.Source for Usage metering (opens in a new tab)
Live stream limits
At most 3 JPEG frames per second; WebSocket message limit 2 MB. Five consecutive measurement failures end the session.Source for Live stream limits (opens in a new tab)
Session duration
Session closes after 30 seconds without a usable media frame; this is an idle timeout, not a maximum total duration.Source for Session duration (opens in a new tab)

Endpoint pricing has not been collected. Check the provider for applicable rates.

Data & enterprise terms

Retention, training use, regional processing and enterprise terms have not been summarized for this endpoint.

Caching

Caching can reuse earlier input processing. Availability, lifetime and billing depend on the endpoint. A cache hit still generates a new response.

01 / INITIAL INPUTProcess & retain

The system processes eligible input and retains reusable state.

02 / LATER REQUESTCheck available state

Reuse depends on matching input, session state and the cache policy.

03 / CACHE HITReuse & generate

Reusing state can reduce repeated work. Any charges follow the billing rules below.

Hume API

Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

How it works
Not collected
Minimum reusable input
Not collected
Lifetime & refresh
Not collected
How to enable it
Not collected
Usage fields
Not collected
Billing rules
Not collected
Limits & data boundaries
Not collected

No verified cache rate for this endpoint. An empty rate is not a zero charge.

Hume API

Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

How it works
Not collected
Minimum reusable input
Not collected
Lifetime & refresh
Not collected
How to enable it
Not collected
Usage fields
Not collected
Billing rules
Not collected
Limits & data boundaries
Not collected

No verified cache rate for this endpoint. An empty rate is not a zero charge.

What the measurements say

No benchmark observations have been added for this model. We do not turn a vendor description into a performance score.

Latency and throughput depend on the host, request size, reasoning settings and load. There is no measured speed or global usage figure in this record.

The record behind the model

Why it is included

Inferred for this exact named Hume API release/service from provider documentation and its public weight inventory. No weights for this identity were identified; public TADA releases are excluded. A service record does not assert a separately disclosed checkpoint or parameter count.

Classification evidence (opens in a new tab)

Sources reviewed