Note: If you’re considering putting video up on CTools, here are some general guidelines and requirements for meeting the 20MB limit.

Movie Content and Movie Length

In general, with a talking head photographed against a simple background, you can expect to get around 9 minutes of video under 20 mb. 320 x 240 is a good size to achieve maximum program length.

Slightly less program length for a mixture of movement with a talking head-around 7 minutes.

You can expect to get about 5 minutes of video with a mix that contains movement –traffic, crowds, etc. Again, having a smaller frame 320 x 240 or even better 240 x180 will give you a better looking frame with minimal artifacts (pixeling).

Example 1 | Example2

Picture (frame) sizes

480 x 360 Good for a talking head with a simple background (solid color wall for example) Good for reading text or translations on screen. Discerning speech patterns or enunciations. Shorter over all length of program.

320 x 240 Good choice for an all purpose movie. Talking heads look good even with a busy background (a library for example) It minimizes artifacts on scenes with any movement – either camera moves or people moving in Frame. Also a good choice for a pre recorded news program.

240 x 180 This size will give you the longest running time at the best quality. Talking heads (close ups) look good. Movement – traffic or groups of people- will look best at this setting.

 

Downside: is that you're looking at it on a very small screen. Not good at displaying text or discerning vocal techniques in language instruction.

Codec Settings (Picture size selection)

• In general, if you have a talking head go for a bigger (480 x360) frame.
• If you have a lot of movement go smaller (320x240 or 240x180).
• It the length is the most important consideration, then 240 is your best choice.

Start with these Codec Settings:

• Mpeg 4 video
• Mpeg 4 Audio Mono
• 15 frames per second
• Limit data rate to 400
• Key frame very 300

File size

If the file size is coming in bigger that 20Mb and you can’t cut the program length...

Try these steps:

1. Reduce frame size.
2. Lower the Data rate to 300. If still to big, try 250. Check your picture. If it’s ok go to 200 Data rate.
3. Lower the Audio sample rate from 44 kHz to 32kHz to reduce file size

For more information contact:

Rob DeMiner
Media Consultant
Video Specialist
demilner@umich.edu

or

John Stewart
Information Services Consultant
jhstew@umich.edu