Mixing formats in the edit
digitalfilms by Oliver Peters
The sheer mix and volume of formats to deal with today can be mind-boggling. Videotape player/recorders – formerly a common denominator – are a vanishing breed. Post facilities still own and use VTRs, but operations at the local market level, especially in broadcast, are becoming increasingly tapeless. Clearly, once the current crop of installed VTRs become a maintenance headache or are no longer an important cog in the operation, they won’t be replaced with another shiny new mechanical videotape transport from Sony or Panasonic.
It all starts with the camera, so the driving influence is the move to tapeless acquisition – P2, XDCAM-HD, GFcam, AVC-HD and so on. On the bright side, it means that the integration of another format will cost no more than the purchase of an inexpensive reader, rather than a new VTR to support that format. Unfortunately this will also mean a proliferation of new formats for the editor to deal with.
The term format should be clarified with tapeless media, like P2. First, there is the codec used for the actual audio and video content (essence). That essence is defined by the compression method (like DVCPRO HD or AVC-Intra), frame size (SD or HD), pixel aspect ratio and frame rate. The essence is encapsulated into a file wrapper (MXF), which holds the essence and metadata (information about the essence). Lastly, in the P2 example, the files are written to a physical transport medium (the P2 card itself), using a specific folder and file hierarchy. Maintaining this folder structure is critical in order that an NLE can natively recognize the media, once it’s copied from the card to a hard drive. read more...
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