Support pre v1.3/r0.21.0 recordings in v1.16

[papr]

Deprecated Recordings

Previously released versions of Pupil Player v1.16 do not support recordings created with

• Pupil Capture v1.2 or earlier, and
• Pupil Mobile r0.22.x or earlier.

This was due to the fact that these recordings are missing meta information that is required for the upgrade to our new Pupil Player Recording Format 2.0. For details see "Missing Meta Information" below.

With this PR, instead of aborting with a "Recording too old" warning, Pupil Player will attempt to infer the missing values from other data in the recording. This inference is not perfect and results in imprecise values and might cause issues when converting recorded Pupil time to wall clock time. For details see "Missing Meta Information" below.

Upgrading will only work in Player v1.16

Since this inference is limited, we will remove the upgrade functionality for deprecated recordings in v1.17. This means, that if you want to open a deprecated recording in v1.17 or later, you will have to convert them to the new format using v1.16 first.

Missing Meta Information

Specifically the following keys in the info.csv file are missing:

• Start Time (System): Recording start time in Unix epoch
• Start Time (Synced): Recording start time in Pupil time

Pupil Player assumes that these timestamps were measured at the same time. This allows for the after-the-effect synchronization of Pupil data with externally recorded data that uses the Unix epoch.

Their value can be inferred from the existing recording, given a roughly known imprecision:

• Start Time (System): The system start time can be inferred using the existing Start Date and Start Time fields (precision: one second). Unfortunately, the Start Time is subject to the system's timezone while Start Time (System) is not. Therefore, its inference is off by the recording's amount of timezone offset.
• Start Time (Synced): This timestamp can be replaced by the earliest known recorded video timestamp in the given recording. In this case, the inference error depends on the startup delay of the cameras. This delay is typically less than a second for Pupil Capture recordings, and 2-5 seconds for Pupil Mobile recordings.

Incorrect Playback

In some cases, deprecated recordings might not be played back correctly in Pupil Player. If this is the case for you, please contact [email protected] for support.