# Recording Format
This section outlines the Pupil Player recording format. We recommend reading it thoroughly if you want to develop software that creates recordings on its own, or processes existing recordings without having to open them in Pupil Player.
# Meta Files
Meta files are essential for Pupil Player. Without them, Pupil Player is not able to recognize a directory as a Pupil Recording.
Pupil Invisible recordings have their own meta file definitions:
info.json. When opened in Pupil Player, the meta info file
will be transformed the Pupil Player Recording Format 2.0.
# Timestamp Files
Timestamp files must follow this strict naming convention:
Given that a data file is named
<name>.<ext> then its timestamps file has to be named
A datum and its timestamp have the same index within their respective files, i.e. the
ith timestamp in
world_timestamps.npy belongs to the
ith video frame in
# Video Files
Video files are only recognized if they comply with the following constraints:
Allowed video file extensions are:
Allowed video file names are:
world: Scene video
eye0: Right eye video
eye1: Left eye video
The video files should look like:
We also support multiple parts of video files as input. For instance:
And their corresponding timestamp files should follow the pattern:
# Video Player Compatibility
In order to open the video files with the majority of video players, you will have to transcode the video stream encoding from mjpeg to h264 and change the color format from yuvj422p to yuv420p. You can use the following ffmpeg command to perform this transcoding:
ffmpeg -i world.mp4 -vf format=yuv420p world_compatible.mp4
# Audio File
An audio file is only recognized in Pupil Player's playback plugin if the file is named
audio.mp4 and there is a corresponding
audio_timestamps.npy file containing the
correct audio timestamps.
These files contain a sequence of independently msgpack-encoded messages. Each message consists of two frames:
- frame: The payload's topic as a string, e.g.
- frame: The payload, e.g. a pupil datum, encoded as msgpack
For clarification: The second frame is encoded twice!
Pupil Player decodes the messages into
Serialized_Dict instance holds the serialized second frame and is responsible for decoding it on demand. The class is designed such that there is a maximum number of decoded frames at the same time. This prevents Pupil Player from using excessive amounts of memory.
# Other Files
Files without file extension, e.g. the deprecated
pupil_data file, and files with a
.meta extension are msgpack-encoded dictionaries. They can be read and written using
file_methods.save_object() and do not have a corresponding timestamps file.