See also: "Global: Formatted Braille Importer..."
"BRF" files are a long-standing Duxbury file format that, with some minor variations, has become something of an industry standard. BRF files are relatively simple "ASCII braille" text files that represent finished braille pages, line by line and page by page, using the North American ASCII-braille convention to represent the braille cells.
The most common case of importing a BRF file is also the simplest. If you have existing libraries of BRF files that are known to be correctly laid out for your embosser, and you simply want to emboss them again as they are, go to the Global: Formatted Braille Importer dialog, and check the box labeled "Read formatted braille without interpretation". This setting causes all other options in the dialog to be disabled (i.e. they will have no effect), and it switches page numbering off.
To open the ".brf" file in DBT, use File: Open. Importing the file will preserve all spaces, line breaks, page breaks - and page numbers - as they are, displaying the exact braille page images in DBT.
To emboss these braille page images, the embosser selected in the Document menu must have page dimensions consistent with the imported braille pages. For example, if the embosser is set for 42 cells per line and 26 lines per page and the imported BRF has the same page size or smaller, the braille output should match exactly the contents of the original BRF file.
While this approach works quite well for "copy" embossing, it does not work at all well for other purposes such as re-flowing the braille for a different page size, changing the braille in any way, or translating braille to print.
During the transition from the traditional English braille codes to Unified English Braille, the desire to re-translate traditional material from a BRF as UEB braille has proven to be a major additional use of importing BRF files. This particular case uses a completely separate import process.
The BRF format is a set of page images. A page image contains only the result of the page formatting process without any "memory" as to how and why it got that way. To permit sensible further editing, DBT must identify the structural elements such as running headers and footers, centered headings, paragraphs, etc., and code them accordingly. On import, DBT must therefore reconstruct these elements, based upon information that you provide in the Global: Formatted Braille Importer dialog.
In this case, the goal of importing the BRF is to create a DBT file that can be edited further. We will explain how this is done using an example.
Let us say that a particular BRF file contains running headers. If you tell DBT in the Formatted Braille Importer dialog that there are headers on each page ("Header Placement"), DBT will know enough to mark the first text on the top line as a running header, i.e. surround it by [tls] ... [tle] codes. Then it will ignore any further top-line text that matches the header on the previous page.
But if you do not tell DBT that running headers are present, DBT presumes that there is nothing special about the text on the top line and treats it as a continuation of the body text from the prior page. The difference becomes immediately apparent if you add or subtract a few lines of text: in the first case, the true body text re-flows sensibly from or to the following page, leaving the running head in place, whereas in the second case the running head shifts along with the adjacent body text, winding up in a nonsensical position.
The same considerations apply to running footers ("Footer Placement") and to both Print Page Numbers (if any) and Braille Page Numbers. For all of these elements you must inform DBT if and where these elements appear on the page.
In addition to the placement of structural elements, you must inform DBT about the page size as it is in the BRF file. The quality of the import will depend critically on that description being accurate. The line width must be exactly correct in order for DBT's recognition of centered headings and right-hand page numbers to work properly. Likewise, the maximum number of lines per page must be correct. (Do not confuse these sizes with those you want to use subsequently.)
Note: For all DBT-generated BRF files except very old ones (from the 1970's) there is a margin for error in the page depth, which must be set at least as large as the actual depth of the page images in the BRF, but which usually can be a line or so larger without harm. That is because most BRF files contain explicit markers at the end of each page.
If you are uncertain that you have correct values for all the required information about the BRF file to be imported, make your best guess, do the import, and inspect the result to see if some parameters need to be changed. If so, discard the imported file, adjust the settings in the dialog accordingly, and re-import.
Incidentally, the "as-it-is" description that you enter in the Global: Formatted Braille Importer dialog may not be the same as the eventual document size you desire. In fact, reformatting may well be what you have in mind when importing. The new page size and new page numbering will be defined in the Global: Embosser Setup dialog and the Document: Page Numbering dialog.
Tip: If you are at all unsure about the settings that you are giving for the existing BRF file, it is generally less confusing to have both sets of settings in agreement at the time of the import, so that you can easily see that everything has come in correctly in the first place. You can then change to the desired page size, etc., in the Global: Embosser and Document settings.
Such imports can be perfectly faithful to the original BRF file, but not in all circumstances. If the "as-it-is" description is accurate and the current page dimensions and other settings are in agreement, it usually happens that the import is perfect in that sense. However, it cannot be guaranteed. That is partly due to some slight (and generally useful) leeway in the input sensing. For example, an input line that is centered with a "right bias" might be marked as centered, which could cause a 1-cell shift when it is re-centered (but with "left bias") in the output. Another possible source of discrepancies can occur when page depths vary slightly, as is permitted in a BRF file.
From version 11.3 upwards, DBT has a separate import method to help you update old (pre-UEB) BRF files into UEB braille. Here is an example situation. You once created English-language braille for a document that has no mathematics in it, and now someone wants that document in UEB braille, but you no longer have the original DBT file. (Note: It is always better to save your DBT files!) However, you do have the braille formatted file. Here are the required steps.
Remember: This import method is for the English language only, with no math!