This thread will help you to run GMod CEF Codec Fix which will ensure you have the greatest possible media compatibility while playing on our servers. GMod CEF Codec Fix patches in codecs which are typically not supported within GMod, which opens the door for us to stream more content to GMod than ever before possible. Prerequisite: Switch your GMod to the "x86-x64 - Testing" branch. You can follow this tutorial to do so, but make sure to select the x86-x64 branch instead of the chromium branch. If you do this correctly, GMod will be displayed in your games list as "Garry's Mod [x86-x64]". Make sure Steam is running when you run the Codec Fix. 1. Go to the Releases tab on GMod CEF Codec Fix Github page. 2. From that page, under Assets, click the appropriate package for your operating system to download the script. Currently, at the time of writing, the fix supports only Windows operating systems. Make sure to download the latest version (closest to the top of the page) to ensure proper compatibility. 3. Run the executable file you just downloaded. The script will open a command window or terminal to proceed with the patching process. If your SmartScreen filter on Windows pops up, be sure to allow the app to run anyway. 4. You will see text which will explain what the script is doing while it runs, and whether or not the files are patched. If the files are not patched yet, the patches will download. Depending on your internet speed, this can take a moment. 5. Once patches are downloaded, they are applied to the appropriate files and you will be prompted to select one of two options of GMod to launch using the numbers 0 and 1. If you are on a 64-bit capable computer, use the 64-bit version; else, use the 32-bit version. Congratulations! If you made it this far, you're done. Luckily the script does pretty much all of the work for us this time. To avoid the file patches reverting to the files included with GMod, be sure to use the GModCEFCodecFix script to launch GMod, or launch GMod via your games list or .exe shortcut only. Using most methods of game launching on Steam forces a file validation pass which will revert these patches. You'll have to run the script again to re-patch the files if you do this.