Handbook:Advanced Server Configuration:Transcoding of Received Facsimile

Transcoding refers to the on-the-fly conversion of encoded data. HylaFAX supports transcoding of received facsimile so that received documents can be stored in files using an optimal compression algorithm. If the RecvDataFormat configuration parameter is set it defines the format for writing received facsimile data, one of: "1-D MH", "2-D MR", "2-D MMR", or "adaptive". An "adaptive" format is the default; it causes the received data to be written using the data format negotiated by the sender and receiver. Using

RecvDataFormat: "2-D MMR"

gives the most space-efficient data format. (Since 2-D MMR is the most sensitive to line errors if you see lots of pages ending in half you may try to lower the compression efficiency (to 1-D MH) to make it less prone to errors.)

Note that RecvDataFormat defines the encoding of the page data, not the file format: this is always TIFF.