YOP File

What are YOP files and how to open them

Are you having problems opening a YOP file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your YOP files.

What is a YOP file?

A .YOP file is a Psygnosis YOP Video file.

Psygnosis YOP Video is a proprietary video file format used by Psygnosis, a former British video game developer, for full-motion video (FMV) cutscenes in their 1997 game The City of Lost Children on DOS and PlayStation. Its main purpose is to store animated video scenes (video plus audio) that the game engine plays during certain story moments. Because these files are not standard video files, typical media players usually cannot play them without special support.

Files with the .YOP extension are generated by the game during development, or as resources packaged in the game's data. The format wraps together a video stream and an audio stream: the video component is a palette-indexed (palettised) frame-by-frame stream, and the audio uses IMA ADPCM compression at a sample rate of 22050 Hz, mono. To view or use a YOP file outside the game, it must be decoded by software that understands its container and compression. FFmpeg includes a demuxer and decoder for YOP that extracts both video and audio streams.

Internally, YOP files begin with the ASCII-like signature "YO" followed by a control byte, located at file offset 0, which helps identify them. Following this, the header includes fields for frame rate, frame size (number of video frame bytes per block), video width and height, extra data including palette size and audio block length. These fields are used by the decoder to allocate buffers and interpret the encoded video and audio blocks correctly.

How to open YOP files

We have identified one YOP opener that is compatible with this specific type of YOP file.

Programs that open Psygnosis YOP Video files

Last updated: August 14, 2026

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