• 7.6.1. Color Fax Features
• 7.6.2. Using the Fax API Library for Color Fax
• Sending a JPEG Fax
• Sending a JPEG-only File
• Receiving a JPEG File
• Receiving a JPEG Fax

7.6. Color Fax

Color Fax functionality includes enhancements to the R4 Fax API Library to support sending and receiving of JPEG files to and from Group 3 color fax devices.

7.6.1. Color Fax Features

Features of the Basic Color Fax include the following:

• R4 on DM3 Fax API Library
• Support for up to two DM/F240 PCI boards
• Transmission and reception of JPEG encoded color facsimile images to and from color fax devices
• Encoding of color fax images using the JPEG format as specified in ITU Rec. T.85 standard and the ITU Rec. T.4 Annex E standard (ITU Rec. T.85 defines a specific color profile for color fax images. ITU Rec. T.4 Annex E defines the specific JPEG profile for color fax.)

The following baseline JPEG options are supported (as defined in ITU Rec. T.4 Annex E):

• Baseline DCT with Huffman entropy coding
• CIElab color space (L=Luminance [also used for grayscale], A=green/red hue, and B=blue/yellow hue)
• 8 bits/pel/component
• 4:1:1 sub-sampling
• One scan per image file
• Default CIE illuminant D.50
• Default gamut for LAB
• G3FAX APP1 marker: Version=1994 and resolution=200 dpi

7.6.2. Using the Fax API Library for Color Fax

This section includes information about the Fax API library used for color fax.

NOTE:

A sample JPEG file is provided with the software. The file name is colour01.jpg. This file has the correct JPEG characteristics, so it can be used as a reference image when testing color fax transmissions.

• Two new keywords have been added: DF_JPEG_GREY and DF_JPEG_COLOR. They are intended to be used with a IOTT (iott.io_coding field) that has io_datatype = DF_RAW.
• To enable the JPEG mode for sending or receiving, FC_TXCODING must be set to DF_JPEG_GREY or DF_JPEG_COLOR (this implies automatic DF_MMR and DF_ECM).
• In order to receive in JPEG, the application must receive fax in raw format. Also, ATFX_CODING must be set to DF_JPEG_GREY and DF_JPEG_COLOR, if JPEG files are transmitted.

The R4 FAX API allows you to control many aspects of the T.30 protocol. The only commands you have to configure are the line settings:

• FC_TXCODING
• FC_TXBAUDRATE
• FC_RXBAUDRATE

The basic approach is to extend FC_TXCODING:

#define DF_MH           0     // 1-D Group 3 Modified Huffmann encoding  
#define DF_MR           1     // 2-D Group 3, T.4 Modified Read encoding  
#define DF_MMR          2     // T.6 Modified Modified Read encoding  
#define DF_JPEG_GREY    3     // set ECM and T6 + JPEG    (<--- ignore DF_ECM value)  
#define DF_JPEG_COLOR   4     // set ECM and T6 + JPEG Full Color  
#define DF_ECM          0x8000     // OR with FC_TXCODING value to use ECM

This is valid for sending and receiving.

Sending a JPEG Fax

1. Set fx_setparm( ) FC_TXCODING = DF_JPEG_GREY or DF_JPEG_COLOR
2. Fill the IOTT:

     Iott->io_type      = IO_DEV | IO_EOT;  
     Iott->io_fhandle   = dx_fileopen("d:\\F21_200.jpg", _O_RDONLY | _O_BINARY , 0);  
     Iott->io_bufferp   = NULL;  
     Iott->io_offset    = 0;  
     Iott->io_length    = -1;  
     Iott->io_nextp     = (DF_IOTT *) NULL;  
     Iott->io_prevp     = (DF_IOTT *) NULL;  
     Iott->io_width     = DF_WID1728;  
     Iott->io_resln     = DF_RESHI;  
     Iott->io_coding    = DF_JPEG_COLOR  (for JPEG: DF_JPEG_GREY or DF_JPEG_COLOR)  
     Iott->io_phdcont   = DFC_AUTO;  
     Iott->io_datatype  = DF_RAW #(mandatory for a JPEG)

NOTE:

A file can also be sent from memory (IO_MEM instead of IO_DEV)

Sending a JPEG-only File

               FC_TXCODING set to DF_JPEG_COLOR  
     JPEG Color  
              (MPS)  
     JPEG Color  
              (MPS)  
     JPEG Color  
              (EOP)

Additional information:

• If the IOTT contains a JPEG file, and the TX_CODING is not correct (for example, JPEG Color file and TX_CODING is JPEG_GREY), an error is reported.
• If IOTT doesn't contain a JPEG entry, turn off JPEG, even if TX_CODING expects JPEG.
• When there is a JPEG file to send, headers are turned off for ALL the pages (also MH/MR/MMR/ASCII file).
• If you are sending a JPEG file, check that the DIS of the receiving side supports JPEG
• If the user forces a MPS as PhaseD command, or if there is a different JPEG value (Disable/GREY/Color), then an EOM is forced.

Receiving a JPEG File

NOTE:

The only mode supported is RAW.

• FC_TXCODING = DF_JPEG_GREY or DF_JPEG_COLOR
• If the application sets FC_TXCODING to DF_JPEG_GREY or DF_JPEG_COLOR, and if the fx_rcvfax( ) is not issued with the DF_RAW, the function will return an error.
• ATFX_CODING( ) reports DF_JPEG_GREY or DF_JPEG_COLOR.
• As was done previously, FC_RXCODING specifies the receive file, except if ATFX_CODING( ) reports DF_JPEG_GREY or DF_JPEG_COLOR.
• Backward compatibility is preserved with MH/MR/MMR reception.

Receiving a JPEG Fax

          FIS_PrmJPEG_JP_JPEG | FIS_PrmJPEG_JP_FULL_COLOR  
     DCS = QFC3_MsgReportCapsEvt_JPEG_JP_DISABLED  
          ATFX_CODING = DF_MH, DF_MR or DF_MMR  
          -> receive raw file  
     EOM  
     DCS = QFC3_MsgReportCapsEvt_JPEG_JP_JPEG  
          ATFX_CODING = DF_JPEG_GREY  
          -> receive raw file  
     EOM  
     DCS = QFC3_MsgReportCapsEvt_JPEG_JP_FULL_COLOR  
          ATFX_CODING = DF_JPEG_GREY  
          -> receive raw file  
     EOP

Click here to contact Dialogic Customer Engineering