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Relay Event Notification
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Last updated: 2025-09-10 14:23:27
Relay Event Notification
Last updated: 2025-09-10 14:23:27
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Relay callbacks are used to call back status information of relay tasks. You need to configure the callback address in a relay task and then Tencent Cloud CSS backend will call back different results to the specified server.
This document describes the parameters in callback message notifications sent by Tencent Cloud CSS after a stream push/interruption callback event is triggered.

Notes

1. You need to understand how to configure callbacks and how will you receive messages via Tencent Cloud CSS before reading this document. For more information, see How to Receive Event Notifications.
2. If the task has not reached its end time, continuous retries due to source or destination address unavailability, or automatic task migration due to machine abnormalities, will generate task end callbacks. Do not use these callbacks as the final task end callbacks.
3. If you need to determine whether the task is streaming properly, you can do so from the receiving end, such as using the stream interruption callback in Cloud Streaming Services or the stream status query API, etc.

Relay Event Parameters

Event type parameters

Event Type
Parameter Value
Relay
event_type = 314

Common callback parameters

Parameter
Type
Description
appId
int
User APPID.
callback_event
string
Callback event type.
source_urls
string
Pull source URLs.
to_url
string
Push destination URL.
stream_id
string
Live stream name.
task_id
string
Task ID.
msg
string
Different events, detailed callback information.
event_time
string
Event timestamp, for example: 1712893433.

Parameters in msg

Parameter
Type
Description
task_start_time
int
Task start timestamp, in milliseconds.
url
string
Source URL of the current pull task.
index
string
Index of the list for on-demand files.
duration
int
Duration of an on-demand file, in seconds.
task_exit_time
int
Task stop timestamp, in milliseconds.
code
string
Task stop error code.
message
string
Task stop error message.
type
string
Alarm Callback (callback_event: TaskAlarm) Usage: Available alarm types include:
PullFileUnstable：Unstable file retrieval.
PushStreamUnstable：Unstable streaming.
PullFileFailed：Failed to retrieve the file.
PushStreamFailed：Streaming failure occurred.
FileEndEarly：Premature termination of file.

Sample callback message

TaskStart - Callback of the task start event
VodSourceFileStart - Callback of the on-demand file’s start
VodSourceFileFinish - Callback of the on-demand file’s end
TaskExit - Callback of the task stop event
{
    "appid": 4,

    "callback_event": "TaskStart",

    "event_type": 314,

    "interface": "general_callback",

    "msg": "{\\"task_start_time\\":0}",

    "product_name": "pullpush",

    "source_urls": "[\\"http://yourURL.cn/live/normal_230753472*****21162358-upload-45eb/playlist.m3u8\\"]\\n",

    "stream_id": "testvod",

    "task_id": "118148",

    "to_url": "rtmp://xxx.livepush.myqcloud.com/live/testvod"
}

{
    "appid": 4,

    "callback_event": "VodSourceFileStart",

    "callback_url": "http://you.callback.url",

    "event_type": 314,

    "interface": "general_callback",

    "msg": "{\\"url\\":\\"http://remit-tx-ugcpub.douyucdn2.cn/live/normal_466247620*****3100448-upload-216b/playlist.m3u8\\",\\"index\\":0,\\"duration\\":14920}",

    "product_name": "pullpush",

    "source_urls": "[\\"http://yourURL.cn/live/normal_466247620*****3100448-upload-216b/playlist.m3u8\\"]\\n",

    "stream_id": "testvod",

    "task_id": "118145",

    "to_url": "rtmp://xxx.livepush.myqcloud.com/live/testvod"
}

{
    "appid": 4,

    "callback_event": "VodSourceFileFinish",

    "callback_url": "http://you.callback.url",

    "event_type": 314,

    "interface": "general_callback",

    "msg": "{\\"url\\":\\"http://yourURL.cn/live/normal_466247620*****3100448-upload-216b/playlist.m3u8\\",\\"index\\":0,\\"duration\\":14920}",

    "product_name": "pullpush",

    "source_urls": "[\\"http://yourURL.cn/live/normal_466247620*****3100448-upload-216b/playlist.m3u8\\"]\\n",

    "stream_id": "testvod",

    "task_id": "118145",

    "to_url": "rtmp://xxx.livepush.myqcloud.com/live/testvod"
}
{
    "appid": 4,

    "callback_event": "TaskExit",

    "event_type": 314,

    "interface": "general_callback",

    "msg": "{\\"message\\":\\"write packet error.\\",\\"code\\":-22,\\"task_exit_time\\":0}",

    "product_name": "pullpush",

    "source_urls": "[\\"http://yourURL.cn/live/normal_230753472*****21162358-upload-4\\"]\\n"
}
Note:
Sequence of callbacks for relay tasks with “Video on-demand” as the source content: TaskStart - Callback of the task start event > VodSourceFileStart - Callback of the on-demand file’s start > VodSourceFileFinish - Callback of the on-demand file’s end.
There is an interval of up to 2s between TaskStart and VodSourceFileStart callbacks.
Callback settings are included in the relay task configuration. For detailed directions, see Relay.
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