[DominikHoffmann]

The Elope commercial is 7.9 MB. This is achieved by using the Sorenson 3 codec, 24 fps, at 480 x 360 pixels and millions of colors. The audio compressions is done via the QDesign Music 2 codec at 44.1 kHz, in stereo and with 16 bits. The duration is just over one minute.

My own movie, which was edited in iMovie, only compresses to 11.3 MB when exported to QuickTime from within iMovie. The specs on it are Sorenson 3 codec, 12 fps, at 240 x 180 pixels and millions of colors, QDesign Music 2 codec at 11 kHz, in mono and with 16 bits. The movie is very close to two minutes long.

In other words, my movie is 1/4 the size, with half the fram rate, and, albeit being twice as long, not about 2 MB (by comparison to Elope) in size by close to 6 times that. What is going on?

Dominik Hoffmann

[crazycylon]

IMHO the commerical was edited and compressed with Final Cut pro and not iMovie.

Maybe someone else has a better answer.

[mortis999]

Lots of things can contribute to smaller file size of compressed video. For most new video codecs the less motion in the video the better compression you can get.
If I were to compress a 15 sec mov of Jacky Chan kicking butt it would compress to a bigger file size than say 2 minutes of a person sitting in a chair talking. Clean well lit video will compress
better than and old VHS tape of your 6th birthday. Never recompress video.
If you take a mov compressed with Sorenson 2 and recompress it with Sorenson 3 it will be poor quality and most likely bigger than the original file.
If your source file is 30fps and you want to
lower the frame rate cut it in halves / thirds / fourths.

Example
30/15/10/7.5
24/12/8/

Manually setting data rates can be tricky.
Some people use this formula for Sorenson datarates, but

width x height x FPS
-----------------------------
48000

this doesn't always work. I set Video quality at about 50%. If compressing with Sorenson 3 basic, leave key frames unchecked. For data rate start with 64 KB. If it looks good you might try a redo subtracting 16 KB and keep going until satisfied.

For video with audio I always use Qdesign 44 kHz 16 bit at 6 KB (48 kbps)
Audio size is still ridiculously small compared to video, and well worth it.

I hope this helps.

P.S.
Wow I just finished doing a compression test with the basic version of SV3 and I get a wicked shimmer with lower bit rates. I don't have this problem with the dev edition, but then again I don't have image smoothing selected. I wonder if this is contributing to the problem.
If you just have Quicktime 5 Pro I highly
recommend 3ivx.
http://www.3ivx.com/download/macos.html

Happy compressing!

[ 08-10-2001: Message edited by: mortis999 ]

[Randycat2001]

Is it possible that subscribing to the "pro" version of Sorenson unlocks additional compression features? This would reveal additional options in the Quicktime save menu and in turn make those features available in an iMovie export.

[pathogen]

The answer is Media Cleaner Pro 5.

Media Cleaner, without even purchasing the Sorenson Pro codec, has access to bit rate tweaks that really make Sorenson shine. Apple uses it.

And if you purchase the Sorenson Pro codec, you can go even further, not many home users need to go that far though. Media Cleaner 5 is what does the nifty compression trick.

[mortis999]

[ 08-12-2001: Message edited by: mortis999 ]

[DominikHoffmann]

From iMovie 2: The Missing Manual:

"If you're a professional, or soon to become one, $500 buys you something called the Sorenson Developer Edition codec. It offers a number of extremely technical added options that, in the right hands, lead to even better quality QuickTime movies. For example, the Developer Edition generates key frames automatically at the beginning of each new cut, and offers *variable bitrate encoding*--a compression scheme whereby frames filled with motion or transitions get the most "attention" by the data in the movie, and less active frames get correspondingly less. The result is more efficient use of the movie's data--and better visual quality.

"If you've ever wondered why your iMovie films, when exported as QuickTime movies, don't look quite as good as the Hollywood movie ads on the Apple Web site, now you know part of the story."