The Girr format for universal IR Commands and remotes.
- Background and Introduction
- Program support
- The name of the game
- Requirements on a universal IR command/remote format
- Informal overview of the Girr format
- Detailed description of syntax and semantics of the Girr format
- Supporting Java library
- Appendix. Parametrized IrSignals
|2016-04-28||Updated to current version.|
Background and Introduction
There are several Internet sites in whole or in part dedicated to infrared control of customer electronics. Very soon the question on exchange of IR signals, individual or as a set of commands from one remote or one device, comes up. For individual IR signals, the CCF format, also called Hex or Pronto Hex, is the one most used. This describes one signal, without a name or any other attributes. To use, the user will most likely have to copy-paste the information from a downloaded file, or a forum contribution, into his/her application program. For several signals, this unsystematic procedure is both tedious and error prone.
Some manufacturers publish the IR commands for their products, often as tables as Excel list or as PDF documents. There are also some quite impressive user contributed collections around in Excel format, e.g. for Sony and Yamaha equipment. Often, these lists contain not only the CCF form, but even a protocol/parameter form. These lists definitely mark a step in the right direction. With sufficient skills with the involved tools it is often possible to transfer a whole set of commands, possibly even preserving names, with a few clicks. However, this is still a manual process, that is not suited for automation.
On the other hand, there are a few file formats around, describing a complete setup of a programmable remote control, like the Philips Pronto CCF file format or the XCF format of the Pronto Professional. These describe a complete setup, including layout of buttons and pages, font selection and other items not of interest for the exchange of IR signals. The "device updates" (rmdu-files) of RemoteMaster also falls into this category: They do contain the IR Signals, either as a raw representation or in a protocol/parameter format, but also a number of key bindings, more-or-less specific to a particular JP1 remote.
The Lirc project however has a data base file format, containing named commands, grouped into named "remotes". However, the Lirc format was never intended as an exchange format, and, as a general rule, only Lirc program can read Lirc files. Also, Lirc has not a viable concept of intro- and repeat sequences.
This leads to our mission:
To define a universal format for the exchange of IR signals, encompassing both for protocol/parameter form, and different textual formats, like CCF. The format should describe the IR signals with their names, (not their semantics). The commands should be bundled within "remotes". It should be readable and writable by both humans and programs. The format should be free/open for everyone to implement, in open or proprietary contexts. It should use open technology, so that tools can be implemented using currently spread free software.
Everyone is invited to implement this format in other programs, or tools for the format.
IrScrutinizer uses Girr as its preferred format for import and export of IR signals. It can import and export from many different file formats and data bases.
My earlier programs IrpMaster and IrMaster generate XML format output, that is similar, but unfortunately not compatible with Girr. (It can be considered as a predecessor to Girr.) However, the distribution contains an XSLT stylesheet irpmaster2girr.xsl that can be used to translate to Girr format.
The rights to the described format, as well as the describing file are in the public domain. That also goes for the present document. Note that this is in contrast to other documents on www.harctoolbox.org for which no copying or re-distribution rights are granted, or the therein contained software, which is licensed under the Gnu General Public License, version 3.
The name of the game
Pronounce "Girr" as one word (not G.I.R.R.), but otherwise any way you want. It should be used as a proper noun, capitalized (not uppercase). Preferred file extension is girr, but this is not necessary. Also, e.g. xml is possible.
Requirements on a universal IR command/remote format
It should be an XML file determined by an XML Schema. It should, however, be usable without validating parsers etc.
The formal rules (enforced by Schema) should be as non-intrusive as possible, possibly prohibiting "silliness", but otherwise requiring at most a minimum of formal syntactic sugar.
A remote is in principle nothing else than a number of commands. In particular, it should not determine the semantics of the commands, nor does it describe how to control a device that can be commanded by the said remote. Names for commands can be "arbitrary", in any language or character set, using any printable characters including white space. A well defined semantic of command names is not granted. However, in some cases uniqueness in the purely syntactical sense is required, for example ensuring that all commands within a particular commandSet have unique names.
It can be assumed that all signals consists of an intro-, an repeat-sequence (any of which, but not both, may be empty), and an optional ending sequence.
It should be possible to describe signals either as parametrized protocols, in raw form, or in CCF form. If several forms are present, it should be clear which one is the primitive form, from which the others are derived.
It should be suitable both for human authoring (with a minimum of redundancy), as well as machine generation (where simple structure may be more important than minimum redundancy).
It should be a container format, namely extensible with respect to textual representation of IR Signals and -sequences.
- The present work aims at a description for remotes, not devices (e.g. in the sense of this). Thus, command names are free form strings, with no semantics inferred.
- Only unidirectional "commands" are considered, not data communication.
- It is only attempted to define IR signals and "sufficiently similar" signals. One such signal/sequence consists of a sequence of durations, namely alternating on- and off-times. Except for the "normal" IR signals, this includes RF signals of frequencies 433, 318, 868 MHz etc. used e.g. for controlling power switches.
Informal overview of the Girr format
There are four different high-level element in the format: remotes, remote, commandSets, and commands. All can be the root element of a conforming Girr document, although all software may not handle all of them. (Our supporting library only supports remotes as root element.) Basically, the element remotes contains one or more remotes, each containing one or more commandSets, each containing either other commandSets and/or commands.
This element models a command, consisting essentially of a name and an IR signal, in one or several different representations. Names can consist of any printable characters including white space, and carries a priori no semantics.
Consider the following example:
<command name="play" displayName="Play |>" comment="" master="parameters"> <parameters protocol="nec1"> <parameter name="D" value="0"/> <parameter name="F" value="0"/> </parameters> <raw frequency="38400" dutyCycle="0.50"> <intro>+9024 -4512 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -564 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -1692 +564 -39756 </intro> <repeat>+9024 -2256 +564 -96156</repeat> </raw> <ccf>0000 006C 0022 0002 015B 00AD 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 0041 0016 05F7 015B 0057 0016 0E6C </ccf> <format name="uei-learned">00 00 2F 00 D0 06 11 A0 08 D0 01 1A 01 1A 01 1A 03 4E 01 1A 4D A6 11 A0 04 68 01 1A BB CE 22 01 11 11 11 12 22 22 22 21 11 11 11 12 22 22 22 23 82 45 </format> </command>
(Details on syntax and semantics are given in the next section.)
In the parameters element, parameters and protocol can be given. They can be completely given, or they may be inherited from parent element of type commandSet.
The raw and the CCF form may be given next, as above. Finally, one or may auxiliary formats of the signal can be given, here uei-learned.
For the ease of further processing of the result, the sequences within the <raw> element can alternatively be given in the "fat" format, where each flash (on-period) and each gap (off-period) are enclosed in their own element, like in the following example:
<command name="play" displayName="Play |>" comment="" master="parameters"> <parameters protocol="nec1"> <parameter name="D" value="0"/> <parameter name="F" value="0"/> </parameters> <raw frequency="38400" dutyCycle="0.50"> <intro> <flash>9024</flash> <gap>4512<gap> <flash>564</flash> <gap>564</gap> <flash>564</flash> <gap>564</gap>
commandSets bundles "related" commands together. They may contain parameters elements, in which case the values are inherited to children commandSets and their contained commands.
Although a remote cannot contain commands directly — it must contain a commandSet — the use of commandSets is somewhat arbitrary. They can be used e.g. to structure a remote containing a few different protocols, or one protocol and a few different device numbers nicely, in particular if hand writing the Girr file. However, protocol and their parameters can also be given as parameters within the command element.
A remote is an abstract "clicker", containing a number of commands. The name of the contained commands must be unique, even across different commandSets.
remotes, as the name suggests, is a collection of remotes, identified by a unique name.
Detailed description of syntax and semantics of the Girr format
This article describes the Girr format version 1.0, identified by the attribute girrVersion, expected in the root element of an instance. (Not to be confused with the version of the support library.)
The Girr namespace is http://www.harctoolbox.org/Girr.
Except for the "namespace" namespace (http://www.w3.org/XML/1998/namespace), the namespaces XInclude (http://www.w3.org/2001/XInclude) and html (http://www.w3.org/1999/xhtml) are imported. XInclude- and html elements can be used at appropriate places, see the schema.
The grammar of Girr is formally described as an XML schema residing in the file girr_ns.xsd. It contains internal documentation of the semantics of the different elements. The official schema location is http://www.harctoolbox.org/schemas/girr_ns.xsd.
Here is generated schema documentation (thanks to Gerald Manger).
A Girr file can be viewed in the browser, provided that it is associated with a style sheet. This is either a cascading style sheet (css), which essentially tells the browser how different elements are to be rendered, or an XSLT style sheet, which internally translates the XML document to a HTML document, normally with embedded style information. A description of these techniques is outside of the scope of the current document (see this document as an introduction); an example is given as simplehtml.xsl.
To use, add a line like
<?xml-stylesheet type="text/xsl" href="simplehtml.xsl"?>
to the Girr file. (Some programs, like IrScrutinizer, can do this automatically.) Note that some browsers, like Firefox, for security reasons limits the usage of style sheets to the current directory.
XSLT style-sheets can however be used for other purposes than the name suggests. Included in the distribution is a "stylesheet" irpmaster2girr.xsl that translates the XML code from IrpMaster and IrMaster to Girr format.
Supporting Java library
For importing and exporting Girr files to Java programs, a Java library is provided. It is documented by its Javadoc documentation. As opposed to the specification as such, it is licensed under the Gnu General Public License, version 3.
Presently, only import of documents having remotes as root element is supported.
At the time of writing, the library carries the version number 1.2.
The library requires the IrpMaster classes, i.e., the irpmaster.jar file.
The sources can be downloaded from GitHub as contained in the "meta-project" harctoolbundle.
Appendix. Parametrized IrSignals
The purpose of this section is to make the article more self-contained. Information herein are described in greater detail elsewhere.
The Internet community has classified a large number of IR Protocols, see e.g. this listing. These protocols consist of a name of the protocol, a number of parameters and their allowed domains, and a recipe on how to turn the parameters into one, two, or three IR sequences, making up an IR signal. This recipe is often expressed in the IRP Notation, which is a compact formal representation of the computations involved. For particular values of the parameters, a rendering engine computes the resulting IR signal, often in CCF, also called Pronto Hex format, or in raw format.