Have You Hugged Your Metadata Today? Part 1

Panasonic 32GB P2 card

It''s going to be an exciting NAB Show for Panasonic. Not only will P2 cards be available at 32GB capacity (with 64GB on the horizon), the company will show AVC-Intra technology with full-raster 1920x1080 capture at 100Mbps—a great upgrade from the native 1280x1080 resolution used in DVCPRO HD 1080. Adobe also has a new bauble for the DVX crowd, specifically native MXF (Media eXchange Format) import from P2 cards, with editing and MXF export in Adobe Premiere Pro 3.1.1 and MXF editing from After Effects.

Why is MXF so important? As our distribution and archival efforts shift increasingly towards digital, the concept of metadata—or descriptive textual data that accompanies the audio and video captured by our camcorders—becomes much more important. After all, if you can''t find the video you''re looking for, it has little value. MXF, an XML-based “container” format that I describe below, incorporates metadata, and it is used by Panasonic to store video on the company's P2 cards.

So here''s the agenda for this month. In the first segment, I''ll take a closer look at Panasonic''s P2 storage cards and the MXF format, describing the advantages of solid-state recording. This will help those unfamiliar with P2 understand how 32GB and 64GB cards will extend these unique benefits to practices that capture video 60 minutes at a time, rather than 60 seconds.

In the second installment, I''ll work through Adobe''s new P2 workflow, which can import and export MXF data and edit directly from and write MXF data directly onto a P2 card. Although it's not perfect, I think Premiere Pro''s MXF-centric paradigm provides a great template for how the industry will work with MXF going forward. Certainly Adobe''s role in editing and digital distribution via Flash guarantees that Adobe will play a significant role in how metadata will be preserved and utilized going forward. To keep this from becoming an Adobe advertorial, I''ll also describe how Apple Final Cut Pro handles P2 data, which in several ways is more elegant than Adobe''s current implementation.

A couple of apologies up front to stave off the hate mail. Installment 1 of this month''s newsletter is entirely focused on the P2 newbie; if you''re familiar with the format, you''ll get a good refresher, but little else. Regarding installment 2, I know that other video editors can import and export data from P2 cards—perhaps some more competently than either Premiere Pro or Final Cut Pro. I chose to illustrate this capability with these two programs because I''m familiar with them, and because of their market share.

If you use another program that handles P2 more adeptly, please write in and let me know how. Be as detailed as possible, especially relating to costs and the complete workflow (import/editing/export) and I''ll do what I can to get your emails posted.

I''ll describe P2 technology within the concept of the AG-HVX200 camcorder, which can record DV as well as DVCPRO, DVCPRO 50, or DVCPRO HD to P2 cards installed in the slots in the back beneath the viewfinder. P2 cards themselves consist of four high-speed SD memory cards configured as a RAID array with an LSI controller, all packed into a PC Card (formerly PCMCIA).

If you have the right slot on your laptop—as I do on my HP Compaq 8710w—and the right drivers from Panasonic, you can pop the P2 card from the camera and insert it into your notebook and start editing. Or you can connect the camera to your computer via a FireWire cable and start editing.

The HVX200 has two P2 slots (some camcorders have as many as five). P2 cards are formatted to FAT 32, which any video gray hair will tell you means that files can''t exceed 4GB in size. During recording, the HVX200 will record one 4GB file, then blithely move on to the next. The camcorder will similarly jump from card 1 to card to 2 after filling up the first card with video data. At maximum current capacities of 32GB per card and 100Mbps for DVCPRO HD, this means a shooting duration of slightly more than 64 minutes. Of course, you can store any format to the P2 card, so at DV rates, you could store more than 4 hours of video on the same cards.

P2 cards are expensive, with the 32GB cards costing $1,549.95 at B&H Photo Video as I write this article. (Obviously, the cards are reusable, and prices have dropped pretty quickly in all fairness to Panasonic.) In contrast, the Sony Premium DV tapes I use for my HDV camcorders cost less than $3 in bulk. In this regard, if your average shot lasts 60 minutes rather than 60 seconds, P2 has historically made little sense.

While everyone but Panasonic wishes that P2 cards were cheaper, the markets primarily served by P2 obviously found the overall economics of the device highly cost effective. For example, in the electronic news-gathering market, where velocity and throughput are key, the ability to hand a P2 card to an editor and have them immediately productive, as opposed to cueing and capturing a tape and then finding the right scene, is obviously alluring.

Similarly, filmmakers typically shoot in very short intervals, and are used to delays relating to loading and unloading film, not to mention the film development time. Dumping the contents of a P2 card to disc where it could be immediately viewed is a huge advantage over true film-based workflows.

None of this even considers the potential economic value of the metadata that accompanies the video stored on P2. Let''s have quick look at the MXF format and then return to the metadata.

Figure 1. Contents of a P2 cartridge stored in MXF.
Click here for a larger image

The Material eXchange Format (MXF) is an open standard developed by SMPTE that wraps video, audio, bitmapped images, metadata and other content types to facilitate the interchange and archiving of that content. MXF is codec independent, and can handle DV, DVCPRO, MPEG-2, DVCPRO HD and any number of additional formats, each stored separately, and tied together via a simple XML file.

For example, Figure 1 shows the contents of a P2 cartridge stored in MXF format. The compressed video from the DVCPRO HD stream is stored in the video folder, and the audio is in the audio folder, with bitmapped icons in the icon folder. An XML file in the clip folder ties them all together and contains the metadata.

Figure 2. Adding metadata with Panasonic''s P2 viewer. That''s Roni Stoneman, of Hee Haw fame, playing at Stringbean in Galax, Va.
Click here for a larger image

The vision of MXF is camera-to-archive storage in a single format recognized by every system in the chain. Obviously, metadata plays a significant role in the overall value of the format. For example, I used Panasonic''s P2 viewer to add the metadata to the clip shown in Figure 2. During editing, I could view this metadata to identify the right clip, and years later, in a digital archive, I could search for clips shot of this artist (the fabulous Roni Stoneman), by this shooter or at this location, or by another other item in the stored metadata. Sometime in the not-so-distant future, Internet viewers will be able to search streaming stockpiles for the same videos.

Obviously, after you take the trouble to enter this data, a video editor''s ability to ingest, preserve, extend, and export the data back into MXF format is key. And that''s just what we''ll be exploring in our next segment.