> > >From: Steve Jolly <[EMAIL PROTECTED]> > > >>[EMAIL PROTECTED] wrote: > >> Proprietary file formats are a bad idea. My PDA reads JPEG, dammit! > >> Hopefully, Raw formats will standardize and become availible to > >> programmers outside of the company that originated them. > > >My understanding is that the RAW format is literally the raw data read > >straight off the sensor. A "standard" RAW format would be next to > >impossible, as it would have to take into account every possible future > >advance in sensor technology. > > Probably not quite the case. > > Consider what the camera is likely to actually store as "raw". The data > straight off the sensor would presumably be a collection of small > integers indicating the amount of light that struck each pixel, plus > perhaps some data about how the camera was set up and how the bayer > grid was arranged. > If you had a header that accounted for camera parameters (as the JPEG > header can hold EXIF) and then a raw format body that began with a simple > header that said "a times b integers 0-255 follow" you could handle > any resolution sensor trivially. You could use the same data organization > (file format) regardless of the amount of data. Really all a CCD does > is to react simply to light exposure, just as a film "grain" does.
Strange as it may seem, you're not the first to come up with this idea. The Pentax RAW format uses a standard (TIFF) layout to store everything. The raw sensor data is a single-strip TIFF image, with each 12-bit pixel value stored as a 16-bit integer (TIFF doesn't support 12-bit integers). The EXIF data uses standard EXIF tags (which are modelled after TIFF). There is a (fairly large) section within those EXIF tags that holds manufacturer-specific information, which is where you'll find all the settings, etc., that are not yet defined as part of the EXIF standard, plus anything else Pentax feel they need to put there. Should Pentax go to a higher-resolution sensor, or greater pixel depth, they won't need to change the RAW file format. Contact me off-list (mailto:[EMAIL PROTECTED]) to discuss this further.
