# WTFOS Due to the fixed resolution (810p) of the DJI Goggles V1 and DJI Goggles V2, the font files determine the size of the glyphs displayed in the goggles view. Historically the flight controller has needed to support only a smaller resolution that was dictated by analogue video. This meant that the OSD was rendered onto a smaller area (or SD canvas) but individual OSD elements were large to ensure legibility of the low resolution OSD. Since HD video transmission is now possible and FC firmware now supports a HD canvas, a HD font resolution was needed. The WTFOS system is a collection of modular components that bring discreet functionality. One of these modules is msp-osd. The purpose of this module is to send, receive, record and overlay OSD data in the goggles. The msp-osd module expects a font file input. As of version 0.12+ of msp-osd, the font format has changed from .bin to .png to make it easier for users to create fonts. As of msp-osd 0.12+, default font files for supported flight controller families are stored on the goggles file system with an updated format of .png. Betaflight, INAV and Ardu Pilot default font files have been also updated in look and feel. User created/community font files can be placed on the SD card root folder if the default design is not desired. The expected font file naming is a single `font__hd.png` for HD canvas and a single `font_.png` for SD canvas. The `fcid` is the 4 character flight controller firmware family, such as BTFL (for Betaflight) or INAV. It is also possible to copy a user created font file to the goggles in the case of a missing SD card. Instructions for doing so can be found here -> . --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://sneaky-fpv.gitbook.io/hd-osd-and-tools/fonts/wtfos.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.