Joe Dolson

Accessible Video Library solves a problem in WordPress: the ability to manage videos and manage critical associated media including captions, transcripts, and subtitles for each video.
In WordPress 3.6, WordPress incorporated the MediaElements.js library for showing videos. It’s a good library, and includes native support for captions and internationalization, is keyboard accessible, and supports YouTube.
However, the WordPress implementation doesn’t provide any method to add captions, subtitles, or reference YouTube videos. You can always embed YouTube videos using oEmbed, but these videos don’t have much at all in the way of keyboard support.
Accessible Video Library gives you a custom post type that you can use to manage your video media. You can upload captions in .SRT or .DFXP format, upload subtitles also in .SRT or .DFXP format, use the content of the post to include a video transcript, and can reference YouTube videos.
Additionally, you can upload multiple formats of your video files to improve browser compatibility for your videos.
<h4>Translations</h4>
Available languages (in order of completeness): 
German, Portuguese (Brazil), Polish, French, Dutch
Visit the <a href="http://translate.joedolson.com/projects/accessible-video-library" rel="nofollow ugc">Accessible Video Library translations site</a> to check the progress of a translation.
Translating my plug-ins is always appreciated. Visit <a href="http://translate.joedolson.com" rel="nofollow ugc">my translations site</a> to start getting your language into shape!
<a href="http://www.joedolson.com/translator-credits/" rel="nofollow ugc">Translator Credits</a>

Accessible Video Library

Generates a library for your video information where you can upload caption files, include transcripts, and upload subtitles for other languages.

Themes4WP

With Themes4WP Youtube External Subtitles you can display subtitles over the YouTube videos on your website (subtitles, texts, comments or lyrics as well).
With this shortcode you can display the custom subtitles over the YouTube videos.
A very lightweight, easy to use plugin. Its overall size is around 11 kb. Scripts are loaded only on pages with the sortcode.
<h4>The Shortcode</h4>
<pre><code>[youtube-subtitles width="640" height="360" id="" sub=""]
</code></pre>
<ul>
<li>id = YouTube ID (e.c. fGPPfZIvtCw)</li>
<li>sub = Subtitle URL (Must be uploaded on your host. External link is deprecated)</li>
<li>width = Video width (default 640)</li>
<li>height = Video height (default 360)</li>
</ul>
<h4>Subtitle Example</h4>
<pre><code>1
00:00:02,000 --> 00:00:06,000
Subtitle 1.1
Subtitle 1.2

2
00:00:28,967 --> 01:30:30,958
Subtitle 2.1
Subtitle 2.2
</code></pre>

Youtube External Subtitles Homepage & Demo 
http://themes4wp.com/youtube-external-subtitles/

Themes4WP YouTube External Subtitles

A plugin to display external subtitles over YouTube videos.

Accessible Video Library vs Themes4WP YouTube External Subtitles