Startup Media
Startup Music
Startup music is music that plays on the main menu when booting up the game, but does not play when returning to the main menu from elsewhere in the game.
Source Engine
Source will play 
sound/ui/gamestartup*.mp3 when it finishes loading the main menu after the application is launched. The asterisk matches anything at all (including nothing), so feel free to give your files descriptive names. If more than one file matches, a choice will be made at random.
All files must be encoded at 44.1 KHz.
Tip:Startup music can be disabled by starting with -nostartupsound.
Warning:Only MP3 files are supported, and they do not loop.
GoldSrc Engine
GoldSrc will play media/gamestartup.mp3 or Redbook CD track 29 when it finishes loading the main menu after the application is launched. The track will loop and continue to play until a map is loaded.
Bug:If the game directory is 
valve, the startup track will continue to play across multiple maps until another track is called!Alternatively, create a file named 
playlist.txt in the mod's root directory and insert the following (adjusting MP3 path accordingly). The track will play every time the main menu is visited, instead of only upon game startup.
"PlayList"
{
"Splash" "sound/music/yourmenumusic.mp3"
}Startup Videos
Startup videos is the video that plays when booting up the game, after the game has reached the end of the list inside the StartupVids.txt file, the main menu appears.
You can change the startup video for a game by placing the following files in the <moddir>/media folder:
valve.avifile - for GoldSrc (Retail/WON version)valve.avifile (or other specified in StartupVids.txt) - AVI, for
Source 2006 or earliervalve.bikfile (or other specified in StartupVids.txt) - Bink Video, for
Source 2007 and later, also Team Fortress 2 branch but only in 32-bit mode.valve.webmfile (or other specified in StartupVids.txt) - WebM, for GoldSrc (post-25th anniversary update), and CS:GO engine branch, Team Fortress 2 branch (64-bit only) aswell as Strata Source.
- Please note that in GoldSrc (post-25th anniversary), audio in the WebM video is muted and instead the game will try to play the
<moddir>/sound/ui/valve_sound.wavaudio file, which is much lower quality when played in-game (unless MetaHook is used).
- Please note that in GoldSrc (post-25th anniversary), audio in the WebM video is muted and instead the game will try to play the
If you are making a mod for 
Half-Life 2 (or other Source games) you can place any supported video files in your mod's media folder. In order for the video to play when you start your mod you will need to create a StartupVids.txt file in the media folder. Inside StartupVids.txt you simply specify the filename(s) of the video(s) you want to be played on a separate line.
For example:
Bug:In all games on 
Source 2013, the extension is completely ignored and it will only play bik files. For example, if you set media/video1.mp4 in StartupVids.txt, it will play media/video1.bik instead. Similarly on all Team Fortress 2 branch games, by default it was set to media/valve.avi, but launching in 32-bit will play media/valve.bik and 64-bit will play media/valve.webm instead. (tested in: 
, 
, 
)Supported File Formats
- AVI is supported in GoldSrc (before 2003 & Steam), and Source (before Orange Box branch / Source 2007)
Note:Keep in mind that an AVI video will need to be encoded using the Cinepak codec. It is not known whether audio codecs other than Microsoft ADPCM are supported.- Note:DivX is also supported, however there appears to be a size limit to the startup video, so if a video is not played then its file size is too large, this has been tested with an AVI file over 100 MB.
- BIK (Bink Video) is supported in all Source games since Source 2007.
- You can get the BINK video encoder for free on Epic Games Tools (formerly RAD) website.
- Note:RAD Tools is a commercial product and can't be used legally without purchasing a license for its use in your Source mods. This was pointed out to be by Jeff of RAD Game Tools.
- Note:In Source 2007, when running the game on Windows Vista or later, only the first few seconds of the video will display. After that it will freeze with a "Not Responding" shown on the game's titlebar (if run on windowed mode), or the Busy cursor appears (with hl2.exe is not responding message displaying if you click on it) and you will only hear the video's sound. This was later fixed in the Source 2013 and
Left 4 Dead engine branches onwards respectively, likely due to implementation of D3D9Ex (Source 2013 only) and SDL 2.0, and these newer games are able to play the startup videos without freezing. Additionally, unlike Source 2013 (and later) or Left 4 Dead engine branch, the startup intro in Source 2007 does not scales at higher resolution.
- MOV (QuickTime) is only supported in
macOS. - WebM is supported in GoldSrc (after
's 25th anniversary update), Counter-Strike: Global Offensive (after Panorama update), Team Fortress 2 branch (when launched in 64-bit only), some third-party Source games.
- Source 2 also support WebM, however the instructions on how to add custom startup videos shown on this page does not apply to any Source 2 games.
To Remove the Startup Video
Simply create StartupVids.txt in media and leave the contents blank.
If you want to skip the startup videos, you can add the -novid parameter to your Command Line.
Note:In 
Postal III, the startup video (except the Zoom Platform) was hardcoded into the a entity on the mainmenu.bsp map instead of the StartupVids.txt file, which would run a command to play all 5 intro files (Akella, RWS, Trashmasters intro, and the Source and Nvidia's PhysX legal and copyright notices). To skip the startup video, rename the following files in p3/media and p3_english/media (or p3_<language>/media) folder:Alternatively, you can also use -nostartupmenu and -dev at the same time to disable loading the main menu map automatically, and skip the intro.