NethCTI server: each video source frame is sent once per connected client → nethcti-server runs out of memory

Description

Steps to reproduce

On a NethVoice with one or more video sources configured and many CTI clients connected
Open the video sources page of the CTI with one or more users
Watch the memory of the nethcti-server process: it grows every second until the process crashes and restarts

Expected behavior

Every frame captured from a video source is sent once to each user subscribed to that source. nethcti-server memory stays stable regardless of the number of connected clients.

Actual behavior

nethcti-server memory grows up to ~2 GB, then the process crashes. On restart all the websocket connections drop, so every CTI client (not only the users watching the cameras) shows a connection error.

Observed on a production installation; lowering the sampling rate (frame-rate = 5000 in rest_cti_streaming) only mitigates it.

Root cause

In com_nethcti_ws.js, evtStreamingSourceChanged broadcasts each frame to the room of the source inside a loop over all the connected websockets:

for (sockid in wsid) {
  wsServer.sockets.in(WS_ROOM[room_name]).emit(EVT_STREAMING_SOURCE_UPDATE, evt);
}

Each subscriber receives the same base64 frame once per connected client (N sockets × M subscribers messages per frame, every frame-rate ms). Reproduced with socket.io 4.8: 150 connected sockets, 3 subscribers, 200 KB frame, 10 frames → ~4500 messages instead of 30 and +930 MB of RSS (vs +16 MB with a single emit).

Suggested fix

Emit the frame once to the room of the source, without the loop over wsid.

Components

nethcti-server (branch ns8, shipped in ghcr.io/nethesis/nethvoice-cti-server)
NethVoice module 1.8 on NS8

Test

PR: nethesis/nethcti-server#379, nethesis/ns8-nethvoice#1167

Setup: NethVoice with at least one video source (camera snapshot URL) with frame-rate = 1000, at least 3 users with the video source permission, several other CTI clients connected (web and/or NethLink).

Test Case 1 - Video source page shows the camera

User A opens the video sources page in the CTI: the image of the source is shown and refreshes about every second
In the browser devtools (WS frames), user A receives one streamingSourceUpdate per frame, not one per connected client

Test Case 2 - Multiple viewers

Users A, B and C open the video sources page at the same time: every user sees the image updating
Each user receives one streamingSourceUpdate per frame

Test Case 3 - nethcti-server memory stays stable

With users A, B and C watching for at least 10 minutes, the memory of nethcti-server (podman stats nethcti-server) stays stable and does not grow towards ~2 GB
nethcti-server does not restart and the other CTI clients do not show connection errors

Test Case 4 - Users not watching

A user connected to the CTI but not on the video sources page does not receive any streamingSourceUpdate

Testing image:

https://github.com/nethesis/ns8-nethvoice/releases/tag/1.8.0-testing.101

Install command:

api-cli run update-module --data '{"module_url":"ghcr.io/nethesis/nethvoice:1.8.0-testing.101"  , "instances":["nethvoice<ID>"], "force": true}'

build(cti): update nethcti-server to sample video sources only with s…

Testing image:

https://github.com/nethesis/ns8-nethvoice/releases/tag/1.8.0-testing.112

Includes nethesis/nethcti-server#380: video sources are sampled only when at least one user is subscribed to them (follow-up of nethesis/nethcti-server#379).

Install command:

api-cli run update-module --data '{"module_url":"ghcr.io/nethesis/nethvoice:1.8.0-testing.112", "instances":["nethvoice<ID>"], "force": true}'

Test Case 5 - No sampling without viewers

With no user on the video sources page, nethcti-server does not request frames from the cameras (no streamingSourceChanged events in the nethcti-server logs, or no requests in the camera access log)
When a user opens the video sources page, the image appears within about one frame-rate interval and keeps refreshing
When the user leaves the page or puts the browser tab in background, sampling stops again; when the tab is visible again, the image resumes updating

Release nethesis/ns8-nethvoice 1.8.0

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NethCTI server: each video source frame is sent once per connected client → nethcti-server runs out of memory #8294

Description

Test

Test Case 1 - Video source page shows the camera

Test Case 2 - Multiple viewers

Test Case 3 - nethcti-server memory stays stable

Test Case 4 - Users not watching

Test Case 5 - No sampling without viewers

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NethCTI server: each video source frame is sent once per connected client → nethcti-server runs out of memory #8294

Description

Description

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tonyco97 commented on Nov 6, 2026

Test

Test Case 1 - Video source page shows the camera

Test Case 2 - Multiple viewers

Test Case 3 - nethcti-server memory stays stable

Test Case 4 - Users not watching

tonyco97 commented on Nov 6, 2026

edospadoni commented on Nov 9, 2026

Test Case 5 - No sampling without viewers

edospadoni commented on Nov 9, 2026

edospadoni commented on Nov 9, 2026

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