Upload of larger recording fails

Details on my setup follow the error description.

I have a dedicated machine for recording. On stopping the recording the log show these lines:

May 22 10:19:21 t14server nextcloud-talk-recording[202716]: INFO:nextcloud.talk.recording.Server:Stop recording: https://wolke.wikimedia.de/ d69iz935
May 22 10:19:21 t14server nextcloud-talk-recording[202716]: INFO:werkzeug:5.75.225.80 - - [22/May/2026 10:19:21] "POST /api/v1/room/d69iz935 HTTP/1.1" 200 -
May 22 10:19:22 t14server nextcloud-talk-recording[202716]: INFO:nextcloud.talk.recording.BackendNotifier:Upload recording /tmp/httpswolkewikimediade/d69iz935/Recording 2026-05-22 10-09-20.webm to https://wolke.wikimedia.de/ in d69iz935 as masin.wiedner
May 22 10:19:23 t14server nextcloud-talk-recording[202716]: ERROR:nextcloud.talk.recording.BackendNotifier:Failed to send message to backend, 3 retries left!
May 22 10:19:23 t14server nextcloud-talk-recording[202716]: Traceback (most recent call last):
May 22 10:19:23 t14server nextcloud-talk-recording[202716]:   File "/var/lib/nextcloud-talk-recording/.local/share/pipx/venvs/nextcloud-talk-recording/lib/python3.13/site-packages/nextcloud/talk/recording/BackendNotifier.py", line 54, in doRequest
May 22 10:19:23 t14server nextcloud-talk-recording[202716]:     response.raise_for_status()
May 22 10:19:23 t14server nextcloud-talk-recording[202716]:     ~~~~~~~~~~~~~~~~~~~~~~~~~^^
May 22 10:19:23 t14server nextcloud-talk-recording[202716]:   File "/var/lib/nextcloud-talk-recording/.local/share/pipx/venvs/nextcloud-talk-recording/lib/python3.13/site-packages/requests/models.py", line 1167, in raise_for_status
May 22 10:19:23 t14server nextcloud-talk-recording[202716]:     raise HTTPError(http_error_msg, response=self)
May 22 10:19:23 t14server nextcloud-talk-recording[202716]: requests.exceptions.HTTPError: 400 Client Error: Bad request for url: https://wolke.wikimedia.de/ocs/v2.php/apps/spreed/api/v1/recording/d69iz935/store
May 22 10:20:23 t14server nextcloud-talk-recording[202716]: ERROR:nextcloud.talk.recording.BackendNotifier:Failed to send message to backend, 2 retries left!

On the Nextcloud server I find this line at the same time:

2026/05/22 10:19:23 [error] 387154#387154: *4075 FastCGI sent in stderr: "PHP message: PHP Warning:  PHP Request Startup: POST Content-Length of 83329723 bytes exceeds the limit of 26214400 bytes in Unknown on line 0" while reading response header from upstream, client: 104.151.103.93, server: wolke.wikimedia.de, request: "POST /ocs/v2.php/apps/spreed/api/v1/recording/d69iz935/store HTTP/1.0", upstream: "fastcgi://unix:/run/php/php-fpm.sock:", host: "wolke.wikimedia.de"

The recording has a size of 83329454 bytes (80 MiBytes). I guess the difference is due to some HTTP stuff. This seems like the recording backend wants to upload the recording en bloc. The web interface, though, has no issues uploading this file. I can only guess that the web interface uploads only fragments of files while nextcloud-talk-recording doesn't. I think I could increase the respective config values to allow 100 MiBytes.

The recording has a duration of 10 minutes. Use cases could include recordings of up to 2 hours, that's 12 times the size then. I cannot see me increase the config values to over 1 GiByte, though.

There are two possible causes for this: I have configured something wrong or nextcloud-talk-recording does something wrong.

My setup:

• The recording backend runs on a decommissioned laptop to make use of hardware accelerated encoding.
  • OS is Debian 13
  • nextcloud-talk-recording is installed using pipx
  • Hardware acceleration does work
  • Upload does work for smaller recordings
• The reverse proxy for the recording backend runs on a cloud VM by Hetzner which in turn proxies requests to the recording backend through an IPsec tunnel to the LAN where the laptop is located
• The Nextcloud instance runs in an LXC on a bare metal server

In principle, all parts are functional and working. But what do I have to do to make the upload of larger files work?

Start with nextcloud/talk/recording/BackendNotifier.py, especially the request sent to the recording store endpoint, and compare it with the logged PHP request-size failure. Check the relevant upload limits in the recording backend and Nextcloud/PHP configuration before deciding whether the client or server is responsible. Done means larger recordings upload successfully without requiring an impractically large limit.