Augmented PFM
From Just Solve the File Format Problem
				
								
				
				
																
				
				
								
				Augmented PFM, or PF4, is a variant of Portable Float Map (PFM) image format, extended to support transparency. PFM is itself an extension of the Netpbm formats.
Identification
Files begin with ASCII "PF4", followed by a whitespace character.
Links
- Synthetic HDR Fire Sequence → "Augmented PFM Format"