proton: Add PROTON_NO_STEAM_FFMPEG to ignore ffmpeg that ships with S…

…team.

CW-Bug-Id: #20923

README.md

@@ -273,6 +273,7 @@ the Wine prefix. Removing the option will revert to the previous behavior.
 |                       | `WINE_FULLSCREEN_INTEGER_SCALING`  | Enable integer scaling mode, to give sharp pixels when upscaling. |
 | `cmdlineappend:`      |                                    | Append the string after the colon as an argument to the game command. May be specified more than once. Escape commas and backslashes with a backslash. |
 | `nowritewatch`        | `PROTON_NO_WRITE_WATCH`            | Disable support for memory write watches in ntdll. This is a very dangerous hack and should only be applied if you have verified that the game can operate without write watches. This improves performance for some very specific games (e.g. CoreRT-based games). |
+| `nosteamffmpeg`       | `PROTON_NO_STEAM_FFMPEG`           | Ignore ffmpeg that ships with Steam. Some videos may not play. |
 | `seccomp`             | `PROTON_USE_SECCOMP`               | **Note: Obsoleted in Proton 5.13.** In older versions, enable seccomp-bpf filter to emulate native syscalls, required for some DRM protections to work. |
 | `d9vk`                | `PROTON_USE_D9VK`                  | **Note: Obsoleted in Proton 5.0.** In older versions, use Vulkan-based DXVK instead of OpenGL-based wined3d for d3d9. |
 

proton

@@ -962,7 +962,9 @@ class CompatData:
             setup_steam_dir_drive()
 
             # add Steam ffmpeg libraries to path
-            prepend_to_env_str(g_session.env, ld_path_var, steamdir + "/ubuntu12_64/video/:" + steamdir + "/ubuntu12_32/video/", ":")
+            use_ffmpeg = "PROTON_NO_STEAM_FFMPEG" not in os.environ or not nonzero(os.environ["PROTON_NO_STEAM_FFMPEG"])
+            if use_ffmpeg and 'nosteamffmpeg' not in g_session.compat_config:
+                prepend_to_env_str(g_session.env, ld_path_var, steamdir + "/ubuntu12_64/video/:" + steamdir + "/ubuntu12_32/video/", ":")
 
 def comma_escaped(s):
     escaped = False