How to Compress Videos for YouTube

by Nalts on June 1, 2007

I get bags of e-mail each week about how to compress videos for online use. Since I use iMovie, I simply select “Share: CD-ROM” and transform a potentially 30 GB iMovie file into a small (10-20) MB .mov file that seems to upload well. (UPDATE: Don’t do this. Do this to get the best compression]. Butterfly.

I’d appreciate if you PC users could identify your software package (Windows Movie Maker, Sony Vegas, etc.) and what compression you select to export your video for use online. I simply don’t know those packages.

Kevin Nalts headshotI’m going to now lay out “Nalts Guide for Good Compression” based on a lot of online research (I’ve listed the best sources listed below).

  1. Output highest size possible. If you’re a perfectionist, part of your goal is to have the largest possible file that you can upload or send, but that’s a little impractical. I don’t need 350 100MB files hogging hard drive space, and I don’t want to wait 20 minutes for the video to upload.
  2. Customize your compression or find good default.Most editing software allows you to customize your output based on dimension, frames per second (fps), keyframes and various formats and codecs. Yuck. Who wants to fuss with that on a regular basis. Try to find a good “default” output that works for you.
  3. Shoot Smart. When you shoot your video you’re actually altering the file size. Avoid rapid movements that aren’t necessary. As Adobe puts it: “reduce the noise.” A wobbly camera or trees blowing in the background will increase the file size. A simple background means less data to encode and compress.
  4. Set your compression specifications based on what the website uses.According to the “Making Movies” blog (see below), here are the specs for YouTube’s flash: It is transcoded (decoded to raw video, then re-encoded) into Flash Video (FLV) format. The video frame size is scaled to no larger than 320×240. The frame rate appears to be between 25 and 30 frames per second, and the video data rate appears to be somewhere around 200 Kilobits (kbps) per second. Audio is reduced to mono and transcoded to a lower bit rate. This transcoding is what’s going on in between the time you complete your upload to YouTube, and the time that the video is finally available for viewing.
  5. Save your source files!I try to save every original file (on iMovie) I create, but that’s getting difficult now that my high-definition camera is producing 3-minute videos that take 30 GB of space. However you want to be able to return to a good resolution for alternative uses (like television) and you want to maintain the ability to change the video.

Additional sources

Note: I plan on revisiting this post based on reader feedback. My list will get longer, and I’d like to broaden the list of good, comprehensive and simple sources (which are hard to find).

Trippy directions

File > Export
Where it says Compress movie for: (select the dropdown and get “Expert Settings”)
When the save dialog opens look at the bottom where it says “Export:” and select “Movie to quicktime movie” and select “Options” to the right of it.
Now the fun part!
Click “Settings” – for Compression Type: select H.264
Where it says Compressor (this is key, this brings your quality of the movie up BIG TIME – move the slider between high and best – the longer the movie the lower it has to be to stay under the 100mb limit – short ones can be a lot higher = better quality.
Click Ok.
Now click “Size”
For Dimensions click the drop down for “320×240 QVGA”
Now, below that is “Preserve aspect ratio using:” check the box and click the drop down and select “Crop” -
click ok.
Final step.
Under Sound click “Settings”
Format: AAC
Channels: Stereo (L R)
Rate: 48.000 khz
click ok.
click ok again.
then save your video where you want it and you’re done!

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