How do you make an 8.5 gig uncompressed video
available on the Internet at 10 megs, or under?
You compress it. The first step is to capture the video. This, in itself, greatly reduces the file size. This video was captured at 640x480, 29.92 frames per second, and compressed on the fly. This reduced the file size to roughly 1.3 gigs. Next, I reduced the image size to 320x240. This reduced the file size by 75%, to roughly 325 megs. I then removed the 3/2 pull down. This reduced to file size by 20 %. 3/2 pull down is done with a telecine, and is the method used to turn a 24 fps film into a 29.92 fps video. It, essentially, doubles a frame every four frames.
3/2 pull down really wrecks Apollo films. All Apollo films were shot at 1, 6, 12, or (rarely) 24 frames per second. When you treat a film shot at 6 fps (as in the Apollo 11 landing, for instance) as a 24 fps film (as has almost always been done in the past) and then run it through a telecine, you end up with a video playing 4 times too fast with 6 doubled frames every second. The Apollo 12 landing was shot at 12 frames per second. Removing the 3/2 pull down resulted in a 24 fps video playing 2 times too fast, but with each frame distinct and individual, and a file size of about 260 megs. I reduced the speed to 12 frames per second, resulting in a video of the correct speed and length.
When I synched the audio, it was very satisfying to have P64 and contact happen right when they were called out. I saved this file totally uncompressed, to minimize artifacts for any future processing, resulting in a file size of over 840 megs.
Next, I rotated each frame by ~ 45 degrees to correct for the camera position. The result gives the accurate real time view that you would have if you were standing in the LM during the Apollo 12 landing, looking out the right window straight ahead but down in the direction of the forward foot pad. This is where the camera was aimed.
The final step was to compress this video for the Internet. I chose
the Sorenson codec. This means that you will need Quicktime
3, or higher, to view this video. Sorenson gives the highest compression,
for a given quality, of any of the codecs I have available. With it I was
able to compress this video from 840 megs to a final file size of under