To: The ROV-UC, all ROV video and frame grab users, ROV pilots, Brian Schlining, Todd Ruston, Mike McCann
From: Video Lab staff

Standard Definition vs. High Definition Frame Grabs

The issue of upgrading the shipboard frame capture system from standard definition (SD) to high definition (HD) resolution has been raised several times recently. The Video Lab has discussed this issue and we would like to bring it to the attention of all ROV users to determine if action is warranted at this time. We need your help in answering some of the questions below.

Frame Grab Facts

Real-time Processing: The shipboard system is configured to capture images directly from the HD camera using VARS, which currently creates PNG files that are also converted to JPG files in post-processing. These file types are both compressed from the original SD resolution. It is possible to specify a higher resolution file type; however, all of our post-dive processes are scripted to run on these two file types.

The majority of the frame grabs taken at sea are not optimal. We estimate that more than 50% of the frame grabs taken at sea are either not useable or not necessary because the target object is out of focus, out of the frame, or there is an over-abundance of shots of the same object. It is just not realistic to expect to capture the best possible frame real-time at sea

The onboard Coolpix camera is also available for taking real-time high-resolution images (2048x1536). However, the flash on the Coolpix camera scares away some animals, e.g., fish, so may not be an option if the organism is to be collected.

Post Dive Processing: When capturing from the video stream in the Digital Lab, the video can be cued to the exact frame of interest and captured using the BlackMagic interface which saves the image as a Photoshop .psd file (~6-9 MB). The image can then be converted to any image format that Photoshop recognizes. This is the best method for capturing a high-resolution HD image for publication purposes or for scientific measurements.

Please note, using VARS, the post dive annotators now regularly supplement at-sea frame grabs with good (i.e. properly cued and focused) frame grabs of additional organisms, geologic features, or equipment of general institute interest. These frame grabs are added to the thumbnails in the expedition database via a nightly process. Therefore, we are now deleting all sub-optimal real-time frame grabs as we annotate. These frame grabs remain available through the expedition database, but are not viewable using VARS.

Current space needs using VARS for SD frame grabs:
Anywhere from 0-300+ frame grabs are taken per dive (~180 is typical).
PNG files = ~300-700 KB each and JPG files = ~50-200 KB each.

HD frame grabs taken in the lab using the BlackMagic Deck Controller:
8+ MB each.

Questions to be considered

Q: What is the function of the frame grabs taken real-time at sea?
A: The standard purpose is to act as storyboard to reference the major events of each dive, for example, samples, interesting events, etc.; therefore, compressed SD images should be sufficient.

Q: What else are these images used for? Are ROV Users utilizing real-time, full resolution images for presentation purposes or publications? If so, what resolution do they require for these purposes? Can all of these cases be dealt with post-dive in the Digital Lab, or with the onboard Coolpix camera?
A: ?

Q: Will the benefits of real-time HD frame grabs outweigh the accumulation of many unusable HD frame grabs?
A: ?

Q: What are the costs of converting to and storing HD frame grabs?
A: A new HD frame grab board is about ~$1,000. The estimated storage space increase is ~10x over SD images. Additional costs include maintenance of the space (clearing off drives on the ship) and effort involved in changing the post-dive scripts to work with HD images.
Q: Estimate of these additional costs?
A: ?

Q: Will writing larger image files bog down the VARS program on the ships?
A: ?

Q: Currently, we have no way of monitoring audio on HD tapes, therefore, someone capturing frames in the lab post-dive using BlackMagic will not be able to hear any audio annotations made at sea (e.g., "releasing a chemical NOW"). In this case it would be much easier to take the frame grabs real-time to mark specific events.
A: Audio comments can be recorded on the digital Betacam tapes and annotated using VARS, then cross referenced to the HD tape.
Q: Is this work around sufficient for every situation?
A: ?

Other considerations?