Hey there, let's get that course video playing for you. The core issue here is that this old course on videolectures.net is almost certainly using Windows Media Video (WMV) format—something modern browsers dumped support for years ago. Flip4Mac (the old go-to workaround) is completely obsolete, and those dead Microsoft links won't help. Flash was never going to fix this either, because this isn't a Flash video—it's a WMV file. Here are your most reliable solutions:

1. Use VLC Media Player (Most Straightforward Fix) #

VLC is a free, open-source player that handles nearly every video format, including WMV, and it still supports macOS 10.12.6. Here's how to make it work:

• Download an older, compatible version of VLC (the latest releases won't run on Sierra—look for VLC 3.0.x builds, which still support your system).
• Once installed, grab the direct link to the WMV file on the course page:
  • Open the course page in Chrome, right-click anywhere, and select Inspect to open DevTools.
  • Switch to the Network tab, then refresh the page. Look for requests ending with .wmv or .asf—that's your video file.
  • Copy that URL, open VLC, go to File > Open Network..., paste the link, and click Open. The video should start playing immediately.

2. Use a Video Download Extension (Easier for Non-Technical Users) #

If digging into DevTools feels too complex, try a browser extension that extracts video links:

• For your older Chrome version (limited by macOS 10.12.6), find an archived version of Video DownloadHelper that supports your Chrome build (stick to trusted sources like the Chrome Web Store's older extension listings).
• Once installed, navigate to the course page—the extension should detect the WMV file and let you download it directly. Play the downloaded file in VLC afterward.

3. Command-Line Option with yt-dlp (Power User Pick) #

If you're comfortable using Terminal, yt-dlp (a maintained fork of youtube-dl) can download the video directly to your computer:

• First, install an older version of Homebrew that supports macOS 10.12.6 (the latest Homebrew won't work on Sierra—you can find the legacy installation command online).
• Once Homebrew is set up, install yt-dlp with this command:

  brew install yt-dlp
  

• Run this command to download the video (replace the URL with your course page link):

  yt-dlp http://videolectures.net/mlss06tw_roweis_mlpgm/
  

• The downloaded video will be in your Terminal's current directory—open it with VLC to watch.

Quick Notes #

• Ditch Flash: Adobe Flash is no longer supported anywhere, and it doesn't solve this WMV issue. Uninstall it if you don't need it for other ancient sites—it's a major security risk.
• Stick to Legacy Versions: All tools you use need to be compatible with macOS 10.12.6. Newer software will crash or refuse to install, so always double-check system requirements before downloading.

内容的提问来源于stack exchange，提问作者jjjjjj