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Evaluation Threshold Event Notification
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Last updated:2025-12-03 17:56:29
Evaluation Threshold Event Notification
Last updated: 2025-12-03 17:56:29
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If you have configured an evaluation threshold callback URL, during the assessment process, the backend will automatically send results meeting the threshold criteria to your callback address in JSON format. You may utilize this callback data for subsequent processing operations.
This document primarily elucidates the callback notification fields transmitted by Tencent Cloud Streaming Services (CSS) to users upon triggering the evaluation threshold event.

Note

This guide assumes that you understand how to configure callbacks and receive callback notifications from CSS. For details, see How to Receive Event Notification.

Evaluation Threshold Event Parameters

Event type

Event Type
Value

Evaluation threshold
event_type = 344

Common callback parameters

Parameter
Type
Description
t
int64
Expiration time, which is the Unix timestamp when the event notification signature expires.
The default validity period of a callback notification from Tencent Cloud is 10 minutes. If the time specified by the t value in a notification has elapsed, then this notification is considered invalid. This prevents network replay attacks.
The value of t is a decimal Unix timestamp, that is, the number of seconds that have elapsed since 00:00:00 (UTC/GMT time), January 1, 1970.
sign
string
Security signature. sign = MD5(key + t).
Note: Tencent Cloud splices the encryption key and t, generates the MD5 hash of the spliced string, and embeds it in callback messages. Your backend server can perform the same calculation when it receives a callback message. If the signature matches, it indicates the message is from Tencent Cloud.
Note:
You can set the callback key in Feature Configuration > Live Stream Callback, which is used for authentication. We recommend you set this field to ensure data security.



Callback message parameters

Parameter
Data Type
Description
appid
int
Business ID.
appname
string
Push stream path.
stream_id
string
Stream ID.
domain
string
Push domain name.
event_time
int64
The time the request was sent, in UNIX timestamp (seconds).
transcode_template_id
int
Transcoding template ID.
watermark_template_id
int
Watermark template ID. Reference evaluation (PSNR/SSIM/VMAF) only evaluates transcoded streams. No watermark template ID is provided.
frames
Array of Frame
The score and time below the threshold during the evaluation period.
function
string
Function category: Assessment.
class
string
Specific evaluation types:
PSNR
SSIM
VMAF
Scoring Without Reference(VQA)

Frame

Single frame evaluation score and time.
Name
Type
Description
score
float
score.
time
int64
UNIX timestamp in milliseconds.

Sample callback

{
    "event_type": 344,
    "appid": 1234576,
    "appname": "live",
    "domain": "abc.record.test.org",
    "stream_id": "livestream1",
    "transcode_template_id": 12345,
    "event_time": 1752130787,
    "frames": [
        {
            "score": 22.78,
            "time": 1752130785280
        },
        {
            "score": 32.75,
            "time": 1752130786281
        }
    ],
    "function": "Assessment",
    "class": "PSNR"
}
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