Root cause for the re-occuring ffmpeg error

[john-]

I see that the fragmenter function concatenate_fragments throws this error whenever there are no fragments:

viseron  | 2025-05-29 14:57:39.141 [ERROR   ] [viseron.domains.camera.fragmenter.camera_1.ffmpeg] - pipe:: Invalid data found when processing input

If there are fragments, then the created playlist does not generate an error in ffmpeg.

Is there any reason to generate a playlist when there are no fragments?

It may be there is a mode in Viseron where this empty playlist does not generate an error. I have not figured that out yet. If that is the case then maybe it should generate a playlist and call ffmpeg only if it is in that mode.

[roflcoopter]

There is no real reason to continue if there are no segments found. The code would have to be changed in order to fix that

[john-]

I can take a look at such a change.

In the code the scenario of an "empty playlist" is not just an unintended side effect of the case in which there are segments. Do you recall what the intent was in explicitly writing out a playlist with no segments?

I have seen references on the Web of doing this to "keep a stream open" when the live content ends. However, I don't see how the code would have accomplished that. I have very limited knowledge of how HLS works though.

[roflcoopter]

That is correct, for the HLS streaming the playlists could potentially be empty at first, but they reload every 5s ish where new segments may have been created.

But the logged error you posted seems to be related to create_event_clip. For that, an empty playlist makes no sense

[john-]

Yes, it is related to create_event_clip. If I disable that function then the error does not occur.

I will do a pull request you can take a look at. From what I can see the error is benign and I may be the only one bothered by it.

[john-]

Here is the pull request

[roflcoopter]

Thank you! Running the CI now and will merge when it is complete