.echoreplay File Format

The .echoreplay file format is a container for nearly raw API data from EchoVR. It is designed to be as simple as possible while retaining all information provided by the API.

Programs that can interact with .echoreplay files:

Program	Functionality
Replay Viewer	Reads the file and visualizes the match.
Spark	Records .echoreplay files from game data.

To record .echoreplay files without writing your own software, you can use the Spark, but the format is designed to be simple enough to let people read and write their own replay files.

The .echoreplay file format is a complete storage format for time-series EchoVR API request data. There are two versions of this format - compressed and uncompressed, both with the same file extension. The compressed version is simple the uncompressed file in a renamed .zip file.

The format for the uncompressed file is as follows:

• One line per API request.
• Each line contains the a timestamp, the tab character, and the full JSON data from the game's API
• Optionally, the JSON data for player bone data is included at the end of the line, separated by another tab character.

Due to the high efficiency of zip compression, binary formats such as .milk (once modified to include all the data necessary for replays) provide only marginal or no benefits over the compressed .echoreplay. These formats also require modification for every API change from the game, unlike .echoreplay.