diff --git a/README.md b/README.md
index a7b6688..abde8f0 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,13 @@ __Firefox:__ contributed by [nanocortex](https://github.com/nanocortex). You can
 
 iOS has strict requirements for video files, requiring h264 or h265 video codec and aac audio codec in MP4 container. This can sometimes be a lower quality than the best quality available. To accommodate iOS requirements, when downloading a MP4 format you can choose "Best (iOS)" to get the best quality formats as compatible as possible with iOS requirements.
 
+To force all downloads to be converted to an iOS compatible codec insert this as an environment variable 
+
+```yaml
+  environment:
+    - 'YTDL_OPTIONS={"format": "best", "exec": "ffmpeg -i %(filepath)q -c:v libx264 -c:a aac %(filepath)q.h264.mp4"}'
+```
+
 ## Bookmarklet
 
 [kushfest](https://github.com/kushfest) has created a Chrome bookmarklet for sending the currently open webpage to MeTube. Please note that if you're on an HTTPS page, your MeTube instance must be configured with `HTTPS` as `true` in the environment, or be behind an HTTPS reverse proxy (see below) for the bookmarklet to work.