Note: This question is about download URLs, not software. The question "How do I download a YouTube video?" deals with software.
What exactly changed for YouTube download URLs a few days ago? How should YouTube download URLs be formed now?
The following URL used to work (downloading this Flash video to disk) but no longer works since the change:
Note: the following information is only to illustrate the problem. I am only interested in the information about how to form download URLs.
This change affected quite a few tools. Here are leads from some Firefox plug-in homepages:
From Video DownloadHelper 4.7.4, 2010-07-22:
"As many of the users noticed, Video DownloadHelper does not work well on YouTube since today. This is due to a very recent change at YouTube. We made a fix that seems to work ok. "
From Easy YouTube Video Downloader 3.4, 2010-07-24:
"Please update to latest version 3.5 in sandbox to get it working again with latest Youtube changes"
From YouTube Downloader, 2010-07-24:
"YouTube has updated their website in a way that breaks YouTube Downloader 2.5.6 and older. We are working on version 2.6 which fixes this problem."
Related: "How do I download a YouTube video?". Some of those tools may be broken now!