reka-ai/cs2-dem-renderer

reka-ai/cs2-dem-renderer

Description: Tools used to convert counterstrike 2 demofiles to videos + annotations

Language: Go

License: MIT

Stars: 0

Forks: 0

Open issues: 0

Created: 2026-06-22T15:51:08Z

Pushed: 2026-06-25T05:40:20Z

Default branch: main

Fork: no

Archived: no

README:

[[Blogpost]](https://reka.ai/news/cs2-10k-a-large-scale-egocentric-counter-strike-2-dataset) [[🤗 Dataset]](https://huggingface.co/datasets/RekaAI/CS2-10k) [[🎮 Viewer]](https://huggingface.co/spaces/RekaAI/CS2-10k-viewer)

Renders Counter-Strike 2 .dem demo files to per-player-round videos with synchronized frame-level metadata (keyboard inputs, mouse deltas, player position). Includes a browser-based viewer for exploring the output.

Built for Linux but can work on Windows with minimal modifications.

How it works

1. Parse (two-pass): extracts per-player spawn/death tick intervals and per-frame button inputs from the demo. 2. Render: generates a JSON action sequence, launches CS2 via Steam with the demo loaded, and lets the server plugin execute the action sequence. 3. Encode: streams raw TGA frames piped from CS2's movie output directory to ffmpeg (VAAPI HEVC), writing .mp4 files in real time. 4. Parquet: writes per-round metadata alongside each video.

Requirements

• Go 1.21+
• CMake 3.14+
• C++ compiler
• ffmpeg with VAAPI support (hevc_vaapi)
• Counter-Strike 2 installed via Steam

Building

1. Build the CS2 server plugin

Counter-Strike 2 updates break compatibility with the server plugin with the main branch built for version 1.41.6.5. See the branches for other game versions.

cmake ./cs2-server-plugin/ -B plugin-build -DCMAKE_BUILD_TYPE=Release
cmake --build plugin-build

Install the plugin:

./install-plugin.sh plugin-build/libserver.so

2. Build the renderer

cd dem-render && go build -o dem-render .

Usage

Steam must be running before invoking the renderer. Run dem-render --help for addional arguments. Arguments must come before the demo path in single-demo mode.

Single demo file

dem-render [flags]

Produces one .mp4 + .parquet pair per player round. By default they land next to the dem-render binary; use --output to choose a directory.

Worker mode — batch directory

Process a directory of .dem files. Already-processed demos are skipped (a .log file marks completion).

dem-render worker --input /path/to/demos --output /path/to/output

Or via environment variables:

CS_INPUT_DIR=/path/to/demos CS_OUTPUT_DIR=/path/to/output dem-render worker

Each demo produces:

• .mp4 + .parquet per player round in the output directory
• .log — success/error log for that demo

Output format

Each .parquet file contains one row with these columns:

| Column | Type | Description | |---|---|---| | video_filename | str | Matching .mp4 filename | | match_name | str | Demo filename stem | | map | str | Map name (e.g. dust2) | | steam_id | uint64 | Player Steam ID | | round_number | int | Round number | | team | uint | 0 = T, 1 = CT | | num_frames | int | Frame count | | fps | float | Framerate (default 48) | | width, height | int | Resolution (default 1280×720) | | total_time | float | Clip duration in seconds | | frame_data | list | Per-frame records (see below) |

Each frame records: actions, mouse_x_delta, mouse_y_delta, position_x, position_y, position_z, rotation_yaw, rotation_pitch.

actions are a string of characters: W A S D J (jump) V (fall) C (crouch) R (walk) [ (left-click) or - for no action.

Viewer

Open viewer/index.html directly in your browser (requires the File System Access API).

Click ⚙ to select a local or remote dataset source.

Features:

• Match browser with map filter
• Synchronized video + action playback
• Mouse delta chart (yaw / pitch)
• XY position minimap

Credits

• demoinfocs-golang by Markus Walther — CS2/CSGO demo parser library used for all demo parsing
• CS Demo Manager by akiver — reference for server plugin implementation
• hl2sdk by AlliedModders — Source 2 SDK headers used by the server plugin
• nlohmann/json by Niels Lohmann — JSON library used by the server plugin to parse the action sequence