UPDATE (March 19, 2015): Get
the latest version (1.8.1), which fixes download issues and adds support for
electrolysis in Firefox Nightly. Thanks everyone for your bug reports and your patience.
Important: If you find bugs, use
these debugging tips and send an email to deadline.support@gmail.com or
create a new issue at github.com.
"Download YouTube Videos as MP4" adds a button to the YouTube video pages, so you can download videos. The download button is displayed below the video player and it looks like any other YouTube button. The extension doesn't include ads and only links to YouTube's download URLs.
How to use it? After installing the extension, go to
YouTube.com and click a video. You'll notice a new "Download" button below the player. Click the button and you can select one of the formats that are available.
What are the download options?Here are the formats you can download using this extension:
*
MP4 360p (480x270, 480x360) - all videos are available in this format. Use it if you want to play videos on an old mobile phone (iPhone 3GS, HTC Desire, Samsung Galaxy S2) or to save space.
*
MP4 720p (1280x720) - HD format, available for an increasing number of videos. Use this format if you want to play higher quality videos on a tablet, laptop or a phone with HD display.
* just in case you need it, you can also download the highest-quality FLV version available:
FLV 240p (426x240).
* 480p and 1080p are no longer available as standalone videos downloaded from
youtube.com. YouTube switched to adaptive streams and uses separate files for video and audio, which need to be merged to get a video file. This is more complicated and requires more advanced tools (ffmpeg), so I haven't added them yet.
How to watch the downloaded videos?After downloading videos, you can play them using free applications like:
*
VLC (Windows, Mac, Linux / play both MP4 and FLV videos) - recommended video player
*
Windows Media Player 12 for Windows 7/8 (play only MP4 videos)
*
iTunes and
QuickTime Player (Windows, Mac / play only MP4 videos).
Using a different browser? The extension is based on
a Greasemonkey script. If you use Chrome, Opera, Safari or Internet Explorer,
install the userscript.
The extension works in:
* the regular YouTube interface
*
the HTML5 experiment 
