Global Speed Extension for Safari

A Safari port of Global Speed - a powerful browser extension for controlling video/audio playback speed and audio effects.

Note: This is an unofficial Safari port for personal use. All credit goes to the original author polywock. Please support the original project!

Prerequisites

• macOS (required for Safari extension development)
• Xcode (free from Mac App Store)
• Node.js and npm
• Basic command line knowledge

Installation Steps

1. Create a Free Apple Developer Account

Step 1: Sign in to the Apple Developer Website

• Visit https://developer.apple.com
• Click Account (top-right corner)
• Sign in with your Apple ID.

Step 2: Agree to the Developer Agreement

• After signing in, you’ll see a prompt to review and accept the Apple Developer Agreement.
• Read and click Agree.

Step 3: Access the Free Developer Resources

Once you’ve accepted the agreement:

• You now have a free Apple Developer account.
• You can access:
  • Xcode developer tools
  • Documentation
  • Sample code
  • Developer forums

Note: To distribute apps / publish apps on the App Store requires a paid membership.

2. Install Xcode

1. Open the Mac App Store
2. Search for "Xcode" and install it
3. Open Xcode once to accept the license agreement

3. Directly use build/unpacked from this Repository

OR

3. Clone the Original Global Speed Repository and Install Dependencies and Build

git clone https://github.com/polywock/globalSpeed.git
cd globalSpeed

npm install
npm run build:prod

This will create a build/unpacked folder with the compiled extension.

4. Convert to Safari Extension

Use Apple's conversion tool to create a Safari-compatible extension:

xcrun safari-web-extension-converter build/unpacked --app-name "Global Speed"

You'll see warnings about unsupported APIs - this is expected. Some Chrome-specific features may not work in Safari:

• offscreen - Advanced audio processing
• tabCapture - Tab audio capture
• userScripts - Some content script features

5. Open the Xcode Project

It will open automatically, if it doesn't use this

cd "Global Speed"
open "Global Speed.xcodeproj"

6. Configure Code Signing

In Xcode:

1. Click on "Global Speed" in the left sidebar (blue project icon)
2. Select "Global Speed" target
3. Go to "Signing & Capabilities" tab
4. Under Team, select your Apple ID (add account if needed)
5. Select "Development"
6. Check "Automatically manage signing"
7. Repeat for "Global Speed Extension" target

Important: Make sure both targets are set to macOS only (not iOS). If you see iOS errors:

• Look for "Supported Destinations"
• Uncheck iOS and iPad, keep only macOS

7. Handle Keychain Popups

When building, macOS will ask for your password multiple times:

• Always click "Always Allow" (not just "Allow")
• This prevents the popup from appearing repeatedly
• If this does not work then try:

security unlock-keychain ~/Library/Keychains/login.keychain-db

• After the build is completed, lock the Keychain manually again using

security lock-keychain ~/Library/Keychains/login.keychain-db

8. Build and Run

1. In Xcode, press the Play button (▶️) or press Cmd + R
2. A simple app window will open with instructions
3. The extension is now loaded into Safari

9. Enable in Safari

1. Open Safari
2. Go to Safari → Settings → Advanced
3. Check "Show Develop menu in menu bar"
4. In the menu bar, click Develop → Allow Unsigned Extensions (for first-time setup)
5. Go to Safari → Settings → Extensions
6. Enable "Global Speed Extension"
7. Grant any requested permissions

10. Use the Extension

• The Global Speed icon should appear in Safari's toolbar
• Click it to access speed controls and settings
• Visit any website with video/audio and test it out!

Known Limitations

Since Safari doesn't support all Chrome APIs, some features may not work:

• Advanced audio effects (offscreen API not supported)
• Tab audio capture (tabCapture API not supported)
• Some content script injection features

Basic playback speed control and most features should work fine.

Development Tips

Keep Extension Running

• Once signed, you don't need to click "Allow Unsigned Extensions" every time
• To reload changes: rebuild in Xcode (Cmd + R)

Update to Latest Version

To update when the original extension releases new versions:

cd globalSpeed
git pull origin master
npm install
npm run build:prod

Then rebuild in Xcode.

Troubleshooting

Extension doesn't appear in Safari:

• Make sure you clicked "Allow Unsigned Extensions" in Develop menu
• Restart Safari completely (Cmd + Q, then reopen)
• Check that both targets are signed in Xcode

Build errors about iOS:

• Select each target in Xcode
• Make sure only macOS is selected in "Supported Destinations"

Credits

• Original Extension: polywock/globalSpeed
• Safari Port: Community contribution for personal use