You can augment your live stream with localized markups that describe interesting moments to re-watch or moments for late comers to catch-up by watching. You do this by sending game data along with your live video data. The game data can be sent from the same machine or a different machine than the one used for live video data.

Upload

The Steam end-point to upload game data is the following:


All of the parameters are supplied with POST.

Server Choice

You need to send game data to the same RTMP server that you will send the live video data to. The game data should be sent after you have already begun your live stream otherwise you will receive 412 HTTP status code. If you are getting 412 even though the live stream is running, it means you are sending the game data to a different RTMP server than the video data which may be caused by using a DNS round-robin URL for the RTMP. By looking at the steamcommunity.com/broadcast/upload/ page, you want to use the explicit RTMP server as pointed to by the green arrow to ensure that the live video data and game data are going to the exact same RTMP server. The other table (red arrow) is a DNS round-robin of RTMP servers located in the same geographic region; using this may result in the game data going to a different server than the video data.

Example

Using the above as an example, I would send my live video stream to rtmp:/br1-sea1.broadcast.steamcontent.com/app and my game data to https://br1-sea1.broadcast.steamcontent.com/broadcast/76561198348711414/upload_gamedata where '76561198348711414' is my steamid which I use for live streaming.

We recommend you send your game data to this API every 2-5 seconds. The game data can be a complete representation from the beginning of the streaming event.

POST Parameters

All of the parameters are required

1. appid : The app being streamed. If this appid changes with subsequent calls we will clear cache of any previous game data.
   
2. rtmptoken : this is the stream key or the RTMP token you received from steamcommunity.com/broadcast/upload. This is the same RTMP token used to permit you to upload your live video data.
   
3. gamedata : JSON game data. The format is described in the next section. Make sure to encode via base64

Game Data Format

The string used for 'name' can optionally be tokens for localization (as in the example above). The parser will replace the token with the translations for each language; English is used as the fallback language if the customers language is not provided. There are no general localize tokens. You must define the tokens via the Rich Presence for the app. You can edit your Rich Presence in App Data Admin for your app. The above example would have the following localization in the apps Rich Presence in the following way:


This would display on screen the following: 'Alpha vs Beta | Dust 2'

More information about rich presence tokens can be found here.

Reference

To see how CSGO thinks about the game data integration, you can look at this document. They can configure their CSGO game client to send game state data to any web server. They show an https://developer.valvesoftware.com/wiki/Counter-Strike:_Global_Offensive_Game_State_Integration to receive the data.

Here is an example of the code that CSGO team used to upload the brackets and markers to Steam Broadcast (not complete example, just the upload code segment): ExampleUpload.js