Recording Timestamp shown as `<unknown>` wehen providing a Recording ID

[KillerGoldFisch]

When creating a recording stream with a recording ID and kind set, the viewer lists the recording with <unknown> instead of the timestamp. (See Screenshots)

We use the C++ 0.23.1 SDK and connection using grpc (rerun+http).

Previously, we used version 0.15.1, where the timestamp was displayed correctly.

Expected behavior

The timestamp should be displayed even if the recording ID was passed to the recording stream.

Screenshots

With recording ID

// m_options->appid = "mqtt_event_rerun"
// a_recordingName = "recordingid"
auto rr = std::make_shared<::rerun::RecordingStream>(
    m_options->appid, a_recordingName,
    ::rerun::StoreKind::Recording);

Without recording ID

// m_options->appid = "mqtt_event_rerun"
auto rr = std::make_shared<::rerun::RecordingStream>(m_options->appid);

Desktop:

• OS: Ubuntu 24.04
• Browser: Chrome 137.0.7151.56

Rerun version

rerun-cli 0.23.1 (default map_view nasm native_viewer release web_viewer) [rustc 1.84.0 (9fc6b4312 2025-01-07), LLVM 19.1.5] x86_64-unknown-linux-gnu release-0.23.1 87bdacb, built 2025-04-25T11:04:25Z
Video features: av1 default ffmpeg nasm serde

Rerun C++ SDK: https://github.com/rerun-io/rerun/releases/download/0.23.1/rerun_cpp_sdk.zip

[grtlr]

Thank you for reporting!

In v0.23 we introduced the concept of recording properties, which allow users to associate metadata with a recording.

By default, the recording start time is send automatically when logging to a recoding starts. A very common use case of logging to a predefined recording ID is to append data to an existing recording. So in this case we don't submit the start time upon initialization.

If you still want to have an associated start time, you can log it manually via our SDKs. Here is a C++ example: [docs/snippets/all/concepts/recording_properties.cpp].

From your screenshot, I get the impression that you're trying to associate a name with a recording? If this is the case, you can use rec.send_recording_name("My recording");. This name will be shown in the viewer and takes precedence over the recording start time in the UI.

I hope this answers your question!

Note self: I think we should improve our documentation around this feature.