user11124: I've got a series of videos that I'm looking to drastically reduce in size. The video content is very simple: text animating on white background with a voice track on top. The text is mostly just subtitles and occasionally an image pops up, sort of like a PowerPoint/Keynote presentation, and it needs to play on iPad at Retina resolution.
In terms of size, here's an example of one of the video files:

Size: 20 MB
Dimensions: 1920 x 1080 
Duration: 5 minutes, 18 seconds
Codecs: H.264, AAC
Color profile: HD (1-1-1)
Audio channels: 2
FPS: 25

If there were a video format with variable frame rate, that would be ideal because so much of the video holds a constant frame for a second or so (like a PowerPoint/Keynote presentation). 
The reason is to reduce download size of a video-intensive app.

user27660: (This may not be considered a complete answer, no matter the Rigid policies. This may be better as a comment.)
You can try using:

H.265 video codec (very efficient — 100-second video of 1080p @60fps was just 6-7 MB even with audio, when recorded with Bandicam screen recorder, which is free).
Mono audio channel
Use a lower bit depth and bit rate for audio as well as color/video.
Take a look at how Khan Academy compresses their vids ohh, sorry, they drop the resolution
Explore the free software HandBrake. It offers variable frame rate compressions.


11124: <p>I've got a series of videos that I'm looking to drastically reduce in size. The video content is very simple: text animating on white background with a voice track on top. The text is mostly just subtitles and occasionally an image pops up, sort of like a PowerPoint/Keynote presentation, and it needs to play on iPad at Retina resolution.</p>

<p>In terms of size, here's an example of one of the video files:</p>

<ul>
<li>Size: 20 MB</li>
<li>Dimensions: 1920 x 1080 </li>
<li>Duration: 5 minutes, 18 seconds</li>
<li>Codecs: H.264, AAC</li>
<li>Color profile: HD (1-1-1)</li>
<li>Audio channels: 2</li>
<li>FPS: 25</li>
</ul>

<p>If there were a video format with variable frame rate, that would be ideal because so much of the video holds a constant frame for a second or so (like a PowerPoint/Keynote presentation). </p>

<p>The reason is to reduce download size of a video-intensive app.</p>
 27660: <p>(This may not be considered a complete answer, no matter the Rigid policies. This may be better as a comment.)</p>

<p>You can try using:</p>

<ul>
<li>H.265 video codec (very efficient — 100-second video of 1080p @60fps was just 6-7 MB even with audio, when recorded with <a href="https://www.bandicam.com/free-screen-recorder/" rel="nofollow noreferrer">Bandicam screen recorder</a>, which is free).</li>
<li>Mono audio channel</li>
<li>Use a lower bit depth and bit rate for audio as well as color/video.</li>
<li><strike>Take a look at how Khan Academy compresses their vids</strike> <em>ohh, sorry, they drop the resolution</em></li>
<li>Explore the free software <a href="https://handbrake.fr/" rel="nofollow noreferrer">HandBrake</a>. It offers variable frame rate compressions.</li>
</ul>
