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The Compression Site

MPEG-4 Video, a test with QuickTime 6 Preview (continued)

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For this test I took approximately 1 hour, 40 minutes of video (100 minutes) and my goal was to fit this footage onto a CD-R disc of 700MB (approximate media cost: 10 cents). The footage was in DV format, 720 x 480 pixels, 29.97fps. In DV format, the file consumed about 22GB or so of hard disk space. My test computer was a Mac G4 733Mhz running OS 10.1.4 with QuickTime Pro installed, then I updated to the QuickTime 6 Preview Edition.

chart - cost of storing in different mediums

I opened up the DV file in QuickTime Pro, and selected Export. I chose the MPEG-4 Video format, and customized the video bit-rate for my desired output. It was actually a pretty simple calculation. I had 100 minutes, and 700MB to store it in. 700 / 100 = 7MB per minute, or .1167MB per second. That means I had up to 116KB per second to store video and audio data. To make things easier, I converted this to bits instead of bytes (by multiplying by 8) and I ended up with 928Kbps available.

I choose 756Kbps for video, and 96Kbps for audio, just to make sure it would all fit in a CD.

Working with other codecs in the past, I realized 720 x 480 in 756Kbps would not be acceptable, so I changed the size to the 320 x 240.

I hit export.

About two hours later (perhaps a little less, I stepped away as the file exported) the footage compression was complete.

The file was 650MB. Great, it would fit on a CD. So I braced myself and began to play the exported MPEG-4 clip.

Beautiful. At 320 x 240, there was little difference in quality between the original and the MPEG-4 version. Doubled (or at full screen) there was a small bit of distortion, but extremely satistifactory for moving 22GB into 650MB! For a file 1/33rd the size, I couldn't complain. (If you take into consideration that a 320 x 240 picture is about 1/4 the size of a 720 x 720 picture, it's about 1/8th of the original file size.)

I was able to play this QuickTime 6 encoded file on both a Windows PC (700Mhz PIII) and another Mac (500Mhz G4) after installing the free QuickTime 6 (Preview) Player.

If you are into digital video (home video or professional) you definitely want to check out QuickTime 6. You'll be able to publish your work with just a CD-RW drive and a spindle of CDs, assuming the MPEG-4 licensing is figured out.

(Note: I was unable to play the file with Windows Media Player or RealOne player, but hopefully soon, as MPEG-4 is a standard.)

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