First underwater 3D stereoscopic video: cenotes diver

For my first underwater 3D shoot, I dove cenote Chac-Mool, which is about 20 KM from Playa Del Carmen (just outside of Cancun). I had never taken my [modified BS Kinetics 3D housing](/journal/2010/07/21/underwater-3d-stereoscopic-video-housing-unboxing-setup/) underwater, so I had to first mount lights on it and do a pool test for buoyancy. Adding 4 lbs made the housing almost exactly neutral, although it is just a little bit back heavy.


I was quite worried because a dark cave is not exactly the best place to use a camera system that relies on auto-exposure for its picture. I set the camera to underexpose 3 units (whatever that means in Sony land) and hoped for the best. The results were actually quite good!

Here is the first clip I processed, which shows Mario, our dive guide, swimming through a halocline (the layer between fresh water and salt water, which is more dense). Don't worry -- the fuzzy halocline water clears up after a few seconds.

Use red-cyan classes to see this 3D video and view full screen for best results!

I'll do a more formal write-up about my 3D workflow when it is fully tested, but at the moment, it includes ClipWrap[^1], MPEG Streamclip, PluralEyes, Final Cut Pro, Dashwood Stereo3D Toolbox, and Compressor. I shot 107 clips (214 total, since each camera shoots separately), taking up a total of 16.6 GB of space (8.3 GB x 2).

[^1]: **Updated 17 Sep 2010:** Every once in awhile, ClipWrap leaves the audio track out of re-wrapped AVCHD video from my Sony CX550V camcorder. There is an easy fix for this, which is to open the Perian preference pane, click "Remove Perian" and then (immediately) click "Install Perian." It appears that Perian gets in a bad state and prevents audio from being transcoded properly. I am now in the habit of always checking my re-wrapped video for an audio channel. Once it fails once, it will fail on every successive re-wrap until Perian is removed and re-installed.

3D workflow is *extremely* time-consuming. It took 148 minutes and 37.668 GB of disk space to download all of my day's clips and process a single 55-second clip for upload to Vimeo:

Download 16.6 GB of AVCHD .mts files (8.3GB x 2) to computer 14 min 16.6 GB
Use ClipWrap to re-wrap 214 AVCHD .mts files as Quicktime .mov 11 min 19 GB -16.6 GB
Preview clips / trash bad clips 30 min -4.53 GB
Convert 2 x 358 MB clips (0:55) to ProRes for testing 35 min 1.34 GB
PluralEyes clip sync 5 min 0.01 GB
Final Cut Pro / Dashwood Stereo3D clip coupling, sequence 5 min
FCP sequence export 1080i ProRes 422 LT 37 min 0.67 GB
Compressor convert to 720p, de-interlace, watermark 11 min 0.048 GB
TOTAL 148 min 37.668 GB -21.13 GB

After deleting all temporary data, I am left with 16.538 GB of new data for the day's work. The master clips (which I backed up onto an external hard disk) are now Quicktime-wrapped AVCHD H.264 video files. I will only convert to ProRes the subclips I choose for whatever little production I make from all of the clips I assemble. It is far too time-consuming and storage-intensive to convert all of my clips to ProRes in the field! I expect both time and data numbers to come down as I start targeting my shots, but since most of the time is actual computer download and rendering time, it probably won't go down that much.

My first underwater 3D was a great success -- I look forward to collecting more 3D footage and sharing them online... although it did take a couple hours for me to process just a single clip. It may take me quite some time to do something more formal.