One for the Pros

[Nathan Beaman]

When you shoot any of the dvcpro formats including HD on the HVX or even DV on the DVX100 it writes metadata to the tape. It's UTF-8 but it manages to basically log most basic camera information(actually pretty much anything that comes up on the display. Aperture, focal lengths - the good stuff. A beautiful part of the DVCPRO codec family is that it has the ability to log and maintain this data.
When editing with Final Cut Pro this data is ingested and stored within the clip and even goes with it on output to tape. If you use "print to video" with an edit and shoot it back out to a dv tape and then play it in the HVX with the display on you'll actually be able to see the clip data for each shot - Similar to many still cameras.

With P2 footage it even embeds the serial number of the camera it was shot on, as well as a ton of other stuff beyond the capabilities of the small about of bits dedicated to this in tape based recording. In P2 recording this stuff is stored in the XML files generated for each clip. The XML files store the metadata that applications like P2 Log and P2 Viewer read. Pretty cool stuff.

My question is, does anyone know how to access that meta data directly or better yet an application that would export the data as a tab delineated text file? Do you know where is is stored? I've been thrashing through XML files and getting some ideas of my own but I'm sure someone must know something more about this. A lot of the information is there, but I'm thinking more on a frame per frame basis. Something that could be used in aftereffects or for color correction in shifting exposure.


Thoff, David S, Barry, anyone?

[Arson]

I believe it only stores that data once per clip, not frame by frame within a clip.

[Nathan Beaman]

I believe it only stores that data once per clip, not frame by frame within a clip.

I think you're right - to an extent. I think it only logs changes similar to key framing.
I just ran a sample test and it definitely logs changes. Though I noticed that the focus distance wasn't coming through - which would be the most useful information to transer into programs such as after effects.

[Indywannabe]

Does any metadata make it to the DVD or QT files? ...or is that pure video/audio?

[David Jimerson]

It's fully-accessible in P2 Viewer and Edius, but that's Windows-only.

[Arson]

Once you process or edit in a NLE/AE etc and encode to DVD you will have lost the meta data. The meta data is just in the hvx's mxf files. If you have an all P2 workflow and edit from the mxf files then there may be some way to preserve it or translate it into Closed Captioning channel or something when you encode it to DVD. Otherwise every time you process the file you will have to find some way to move the meta data to a format that doesn't usually support it. I would do that by treating it as closed captioning you can turn on and off. Or you can just put it in an overlay or slate.

[Nathan Beaman]

actually just looking to export changes and the time at which the changes occur to a text file for import into After Effects for compositing purposes. There is a QT Data export component on the Qt developers site.... hmm