Thursday, January 24, 2008

#68 Wk49 On Location

This week we spent preparing for our first weekend of shooting.

I've got some comments to pass along about how to work with the talent, especially if you're crew. We've also made our lives more difficult by not having put more time into preproduction. Everything is connected, from Producer to production assistant. Things go all bass ackward if you don't communicate .


We're going to be using a Panasonic HVX200, which is an HD camera that has many benefits over the camera we've been using up to now, the Panasonic DVX100.

The first thing is that the menu controls and switches on the outside are mostly the same, so the learning curve is limited to working with the media. The HVX can record to tape, but only standard definition. To record high definition you record to solid state memory cards, called P2 cards. Here are a few reasons on why HD is a better format:
  • Images are 2 to 4 times the size of standard definition
  • There is more color in the video
  • It captures real slow motion and accelerated motion
  • The format is easy to transfer to drive, and easy to edit

Disadvantages include:
  • You can't capture to both tape and P2 card at the same time
  • There is no archival medium in HD, you wipe the card and reuse it after you transfer it to your drive
  • The P2 card is expensive
  • The life of a P2 card is unknown
  • HD footage takes up 2 to 3 times more disk space

In this episode I take a shot at explaining the difference between HD format and HDV format and frankly I don't think I made anything clear. It's useful to know, but not critical, so I'm going to lay it out here. If you need to know more, do some research on your own, otherwise, skip the next three paragraphs.

HD and HDV are capture formats. They're good formats for compressing data so you can fit as much data as possible on what ever medium they require, HD requires P2 cards, HDV can use MiniDV tapes, same as for standard definition. Both HD and HDV record the same resolution, and for all I've been told, the same 4.2.2 color space. Standard definition video records in 4.1.1 color. What qualifies as high end digital video, approaching film quality, is 4.4.4 color. I don't need to explain how it works, it's enough to understand that the capacity to capture all the available color is limited as you move from film, to HD, to SD. By the way, film is a poor second to the color capture capability of our own eyes.

HDV cameras are less expensive than HD cameras for the reasons already mentioned in the advantage list above, real slow motion, etc. HD is easier to edit immediately after capture compared to HDV due to the different compression formats they each use. HDV captures footage in groups of 15 frames, called GOP - Group Of Pictures. The first frame contains all the picture information inside the frame, then each frame following that contains only those pixels that have changed. Take a picture of a wall with HDV and the first frame contains all the info, each of the following frames have no new information and so have no additional data. That keeps the file size down so it will fit on the the tape. If a person or even a fly moves through the frame every frame that records changed information has to record it, because it's not on the first frame. But only the pixels that changed need to be recorded.

And thats fine until you need to edit the video. Then you find you can't cut inside the GOP sections, they're like a single unit. To get past this problem you need to convert the digital video to an intermediate codec that reconstitutes each frame, completely restoring the data to each frame. This of course makes the files larger, but that's the price you pay for editing this format on a digital nonlinear editor like Avid or Final Cut Pro.

Next week we shoot the bar scene Saturday and Sunday.
 
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